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1999-2005 Audi A2 SUV Refrigerant circuit -> Cleaning (flushing) refrigerant circuit with refrigerant R134a User Manual

MY CAR USER MANUAL

Refrigerant circuit -> Cleaning (flushing) refrigerant circuit with refrigerant R134a for Your Audi A2 SUV 1999-2005

Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
After blowing out refrigerant circuit:  
– Renew the following components (vehicle-specific): restrictor  
and reservoir, expansion valve and receiver / desiccant car‐  
tridge ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit (vehicle-specific Workshop Manual) and ⇒ Electronic  
parts catalogue .  
– Depending on the problem, renew air conditioner compressor  
⇒ Heating, air conditioning; Rep. gr. 87 ; Air conditioner com‐  
pressor (vehicle-specific Workshop Manual) and ⇒ Electronic  
parts catalogue , or drain off remaining refrigerant oil from air  
conditioner compressor (removed earlier) ⇒ page 272 (re‐  
newing components of refrigerant circuit) and add specified  
quantity of new refrigerant oil again ⇒ page 333 (approved  
refrigerant oils and refrigerant oil capacities).  
Note  
♦ Replacement compressors contain a certain specified quantity  
of refrigerant oil. For vehicles with two evaporators, it may be  
necessary to additionally add a certain quantity of refrigerant  
oil to the circuit ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐  
frigerant circuit (vehicle-specific Workshop Manual) and  
⇒ page 333 (approved refrigerant oils and refrigerant oil ca‐  
pacities).  
♦ If the air conditioner compressor is not supposed to be re‐  
newed, the refrigerant oil quantity in the air conditioner com‐  
pressor must be topped up in line with the specified capacity  
(pour out refrigerant oil and add the specified quantity to the  
air conditioner compressor or the refrigerant circuit again)  
⇒ page 272 (Renewing refrigerant circuit components) and  
⇒ page 333 (Approved refrigerant oils and refrigerant oil ca‐  
pacities).  
– Completely re-assemble the refrigerant circuit ⇒ Heating, air  
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
– Evacuate and charge the refrigerant circuit as specified  
⇒ page 86 and ⇒ page 91 .  
– Start up air conditioner as specified ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit; Starting up air conditioner  
after charging refrigerant circuit (vehicle-specific Workshop  
Manual) and ⇒ page 92 .  
5.5  
Cleaning (flushing) refrigerant circuit  
with refrigerant R134a  
Vehicles with high-voltage system (hybrid vehicles)  
High voltage! Danger to life!  
The voltage levels in the high-voltage system constitute a safety  
hazard. Danger of severe or fatal injuries from electric shock.  
– Persons with life-sustaining or other electronic medical devi‐  
ces in or on their body must not perform any work on the high-  
voltage system. Such medical devices include internal anal‐  
gesic pumps, implanted defibrillators, pacemakers, insulin  
pumps and hearing aids.  
– The high-voltage system must be de-energised by a suitably  
qualified person.  
100  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Risk of injury - engine may start unexpectedly  
It is difficult to determine whether the drive system of an electric  
vehicle or hybrid vehicle is active. Moving parts can trap or draw  
in parts of the body.  
– Switch off ignition.  
– Place ignition key outside vehicle.  
Risk of damage to high-voltage wiring  
Incorrect handling may result in damage to the insulation of high-  
voltage wires or high-voltage connectors.  
– Never use high-voltage wiring or high-voltage connectors as  
a support.  
– Never prop tools against high-voltage wiring or high-voltage  
connectors.  
– Never bend or kink high-voltage wiring.  
– Pay attention to coding when connecting high-voltage con‐  
nections.  
♦ For all work on vehicles with high-voltage system, note addi‐  
tional warnings for working on such vehicles  
⇒ “1 Warning instructions when working on vehicles with high-  
voltage system”, page 1 .  
♦ If work near high-voltage system components is necessary,  
perform a visual check of the high-voltage components and  
wires to check for damage ⇒ page 2 .  
♦ If work on high-voltage system components is necessary, de-  
energise high-voltage system ⇒ Rep. gr. 93 ; De-energising  
high-voltage system or ⇒ Electrical system; Rep. gr. 93 ; De-  
energising high-voltage system .  
– To minimise the number of automatic engine starts when the  
vehicle's drive system is active during test and measurement  
work, charge the vehicle batteries e.g. with the battery  
charger 60A - VAS 5904- in battery standby mode ⇒ Electrical  
system; General information; Rep. gr. 27 ; Battery; Charging  
battery and ⇒ Electrical system; Rep. gr. 93 ; General warning  
instructions for work on the high-voltage system .  
– For test and measurement work that requires the vehicle's  
drive system to be active (READY) or the ignition to be switch‐  
ed on, move the selector lever to position “P”, activate the  
parking brake and take care to keep well clear of the engine  
when it is running. Set up any tools needed so that they cannot  
come into contact with moving parts.  
5. Refrigerant circuit  
101  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ Move the selector lever to position “P” and activate the parking  
brake before performing test and measurement work for which  
the ignition must be switched on but where the vehicle's drive  
system does not need to be active.  
♦ The status of the drive system (READY) is shown by the con‐  
trol unit in dash panel insert - J285- via the “power meter” ⇒  
Owner's Manual .  
♦ Activating and deactivating drive system ⇒ Owner's Manual  
(note display of control unit in dash panel insert - J285- ).  
All vehicles  
Caution  
♦ If there is a possibility that chemical substances (sealing  
additives) for sealing leaks have been added to the refrig‐  
erant circuit to be flushed, do not connect the air condi‐  
tioner service station to this refrigerant circuit and do not  
clean (flush) this refrigerant circuit.  
♦ Chemical substances (sealing additives) for sealing leaks  
form deposits in the refrigerant circuit which will impair  
operation of the air conditioning system and lead to failure  
of the system (and of the air conditioner service station).  
♦ Customers should be informed that the air conditioner in  
their vehicle contains substances not approved by Audi  
and that the system can therefore not be cleaned (flushed)  
and serviced by your workshop.  
Note  
♦ Audi objects to the use of chemical substances (sealing addi‐  
tives) for sealing leaks in refrigerant circuits.  
♦ Chemical substances (sealing additives) for sealing leaks in  
the refrigerant circuit generally react with the ambient air or the  
humidity contained in it. They cause malfunctioning of valves  
and other components with which they come into contact on  
account of deposits in the refrigerant circuit (and in the air  
conditioner service station being used). These deposits can‐  
not be completely removed from the components affected  
(even by cleaning/flushing). Therefore the refrigerant circuit  
can only be serviced by renewing all components that have  
come into contact with the chemical substances.  
♦ Chemical substances (sealing additives) used to seal leaks in  
refrigerant circuits usually cannot be detected from the out‐  
side; mostly the stickers that are supposed to be attached to  
identify these chemical substances are missing. Therefore, act  
with caution when working on a vehicle whose past you are  
not familiar with.  
•
The best way of removing moisture, impurities (e.g. abrasion  
from a defective air conditioner compressor) and old refriger‐  
ant oil without any unnecessary loss of refrigerant and without  
extensive assembly work, whilst at the same time ensuring  
environmental compatibility, is to clean (flush) the refrigerant  
circuit with refrigerant R134a.  
102  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
The refrigerant circuit is to be flushed:  
– If there is any dirt or similar in the circuit.  
– If vacuum reading is not maintained on evacuating a leak-free  
refrigerant circuit (pressure build-up due to moisture in refrig‐  
erant circuit)  
– If the refrigerant circuit has been left open for longer than the  
normal assembly time (e.g. following an accident).  
– If pressure and temperature measurements in the refrigerant  
circuit indicate that there is moisture in the circuit.  
– If it is uncertain how much refrigerant oil is in the refrigerant  
circuit.  
– If the air conditioner compressor has to be renewed on ac‐  
count of internal damage (e.g. noise or no output).  
Note  
♦ For vehicles with an electrically driven air conditioner com‐  
pressor, see the notes on renewing the electrical air condi‐  
tioner compressor - V470- (damage to the air conditioner  
compressor electronics does not always mean that the refrig‐  
erant circuit has to be cleaned) ⇒ page 277  
♦ If a defective air conditioner compressor is replaced by a com‐  
pressor from a different manufacturer, it is important to check  
whether the refrigerant oil already in the refrigerant circuit  
(from the removed compressor) is also approved for the new  
compressor. If a different refrigerant oil is approved for the new  
air conditioner compressor than for the removed compressor,  
the refrigerant circuit must be flushed ⇒ page 335 .  
– If stipulated by the vehicle-specific Workshop Manual after re‐  
newing certain components  
Tools required  
♦ Air conditioner service station with flushing kit (these air con‐  
ditioner service stations feature the additional function “Flush‐  
ing refrigerant circuit” and the necessary flushing kit for  
refrigerant circuits) ⇒ Electronic parts catalogue (Tools; Work‐  
shop equipment/tools; Air conditioning/heating).  
♦ VW/Audi passenger vehicle adapter set - VAS 6338/1-  
⇒ page 125 and ⇒ Electronic parts catalogue (Tools; Work‐  
shop equipment/tools; Air conditioning/heating).  
5. Refrigerant circuit  
103  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ If no air conditioner service station with flushing kit is available  
⇒ Electronic parts catalogue (Tools; Workshop equipment/  
tools; Air conditioning/heating) and depending on the version  
of the air conditioner service station being used, the refrigerant  
circuit can also be cleaned (flushed with refrigerant R134a)  
using the refrigerant circuit flushing kit ⇒ Electronic parts  
catalogue , (Tools; Workshop equipment/tools; Air condition‐  
ing/heating) however this must then be performed manually.  
⇒ page 109  
♦ Use can be made for vehicles with screw connections at the  
refrigerant circuit of the adapter - V.A.G 1785/7- and adapter  
- V.A.G 1785/8- from the VW/Audi passenger vehicle adapter  
set - VAS 6338/1- . Two adapters - V.A.G 1785/8- are required  
for a vehicle with screw connections at the air conditioner  
compressor and reservoir.  
♦ The adapter set for refrigerant circuits - VAS 6338/1- also con‐  
tains a short filler hose - VAS 6338/31- with 5/8 -18 UNF  
connections and a large inside diameter (commercially avail‐  
able).  
Preparations  
– Discharge the refrigerant circuit ⇒ page 84 .  
– Remove air conditioner compressor ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific  
Workshop Manual).  
Vehicle with restrictor and reservoir  
– Remove restrictor (vehicle-specific) and re-connect pipes ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐  
hicle-specific Workshop Manual).  
– Remove reservoir (vehicle-specific) and re-connect pipes (for  
this purpose, use adapter and filler hose - VAS 6338/31- from  
adapter set for refrigerant circuits - VAS 6338/1- )  
⇒ page 125 and ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual).  
Note  
♦ Although it may be possible to flush the reservoir (depending  
on version), its large internal volume means that it holds too  
much liquid refrigerant. When this refrigerant is extracted the  
reservoir ices up severely, the refrigerant only evaporates very  
slowly and the extraction process takes too long.  
♦ Although it may be possible to flush the receiver (depending  
on version; refer to the description for the specific vehicle), its  
large internal volume means that it may hold too much liquid  
refrigerant. When this refrigerant is extracted the reservoir ices  
up severely, the refrigerant only evaporates very slowly and  
the extraction process takes too long.  
Vehicle with expansion valve and receiver  
– Remove receiver (vehicle-specific; not necessary on all vehi‐  
cles) and re-connect pipes (for this purpose, use adapter and  
filler hose - VAS 6338/31- from adapter set for refrigerant cir‐  
cuits - VAS 6338/1- ) ⇒ page 125 and ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
104  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ Depending on the design, the receiver can be flushed (if nec‐  
essary, remove desiccant cartridge installed in receiver)  
⇒ page 125 and ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual).  
♦ If the receiver is attached to the condenser (e.g. on the Audi  
A3 from model year 2004 onwards), it must not be removed  
for flushing (its design makes it suitable for flushing, and it is  
only renewed after flushing) ⇒ page 125 and ⇒ Heating, air  
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
♦ In the case of condensers with an integrated receiver / desic‐  
cant cartridge which cannot be renewed separately or which  
are not available separately, the condenser is to be renewed  
after flushing. On these vehicles, renew the condenser to‐  
gether with the receiver ⇒ Heating, air conditioning; Rep. gr.  
87 ; Refrigerant circuit (vehicle-specific Workshop Manual)  
and ⇒ Electronic parts catalogue .  
♦ Depending on the version, receivers on which the desiccant  
cartridge can be renewed separately may be provided with an  
additional filter element which may have to be renewed to‐  
gether with the desiccant cartridge.  
– On vehicles with a desiccant cartridge in the receiver at the  
condenser (vehicle-specific), remove the desiccant cartridge  
and re-seal the opening at the receiver ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual).  
– Remove the expansion valve (vehicle-specific) and replace it  
with an adapter from the adapter set for refrigerant circuits -  
VAS 6338/1- ⇒ page 125 and ⇒ Heating, air conditioning;  
Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop  
Manual).  
– On vehicles with one or more shut-off valves/non-return  
valves, remove the valves and replace with suitable adapters  
(or hand shut-off valves) from the VW/Audi passenger vehicle  
adapter set - VAS 6338/1- ⇒ page 125 , ⇒ Heating, air con‐  
ditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
Note  
If there is no suitable adapter for the expansion valve in the VW/  
Audi passenger vehicle adapter set - VAS 6338/1- , the removed  
expansion valve can also be drilled open (the old expansion valve  
generally has to be renewed and is therefore no longer needed).  
Caution  
♦ Take care not to damage the sealing surfaces on the ex‐  
pansion valve when drilling it open.  
♦ Otherwise, refrigerant will escape at damaged sealing  
surfaces.  
Drill open expansion valve.  
5. Refrigerant circuit  
105  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ Before drilling open, remove the control element and then drill  
open the expansion valve using a suitable drill bit for example  
(bit diameter e.g. 6.0 mm).  
♦ Certain components have to be removed from the expansion  
valve before drilling it open.  
♦ There are different expansion valve versions with different de‐  
signs. With version -A-, the parts -B-, -C- and -D- have to be  
removed for example. Then separate part -E- (control ele‐  
ment) from part -D-. After doing so, use a suitable bit to drill  
open the expansion valve in area -F-.  
♦ With version -G-, the parts -H-, -I- and -K- must be removed  
for example and the area -L- then drilled open using a suitable  
bit.  
– Remove swarf remnants from the expansion valve after drilling  
open.  
– Re-install the parts -B-, -C- and -D- with version -A- or part  
-H- with version -G-.  
Note  
On vehicles with two evaporators, the circuit to the second evap‐  
orator must be separated from the circuit of the first evaporator  
and flushed in a separate operation ⇒ page 125 and ⇒ Heating,  
air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
Flushing  
– Check that the air conditioner service station contains at least  
6 kg of refrigerant R134a.  
Note  
If applicable, switch on the heater attached to the air conditioner  
service station for the refrigerant cylinder installed in the air con‐  
ditioner service station prior to the first flushing operation (to  
increase the pressure in the refrigerant cylinder) and switch it off  
again before the first extraction operation during the flushing cy‐  
cle.  
– Discharge the used oil container of the air conditioner service  
station.  
– Connect the supply hose (high-pressure end) of the air con‐  
ditioner service station with an adapter to the low-pressure  
pipe to the air conditioner compressor (pipe with larger diam‐  
eter) ⇒ page 125 .  
– Connect the return hose (low-pressure or suction end) of the  
air conditioner service station to the outlet of the refrigerant  
circuit flushing kit.  
– Connect the inlet of the refrigerant circuit flushing kit with an  
adapter to the high-pressure pipe to the air conditioner com‐  
pressor (pipe with smaller diameter) ⇒ page 125 .  
106  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ The components are always (with the exception of the electric  
air conditioner compressor) flushed in the opposite direction  
to the refrigerant flow during air conditioner operation  
⇒ page 111 .  
♦ When flushing, impurities from the refrigerant circuit ingress  
into the refrigerant circuit flushing kit and the air conditioner  
service station, where they are retained in the built-in filters  
and dryer. Depending on the nature of the impurities, these  
components should be renewed more frequently in accord‐  
ance with the operating instructions for the air conditioner  
service station or the refrigerant circuit flushing kit.  
♦ Depending on the nature and severity of the contamination of  
the flushed refrigerant circuits, the filter in the refrigerant circuit  
flushing kit should be renewed at the latest after 5 to 10 flush‐  
ing cycles (flushed vehicles). After flushing a severely conta‐  
minated refrigerant circuit (the refrigerant oil from the refriger‐  
ant circuit is black and viscous or there is a lot of swarf in the  
refrigerant circuit), renew the filter. In the case of such severely  
contaminated refrigerant circuits it is also appropriate to flush  
the circuit again after renewing the filter.  
♦ Depending on the nature of the impurities, dirt (used refriger‐  
ant oil and abrasion from air conditioner compressor) accu‐  
mulates at the sight glass of the refrigerant circuit flushing kit.  
If applicable, clean this sight glass after flushing and flush the  
refrigerant circuit again in one operation as a check (one op‐  
eration is then sufficient).  
♦ Liquid refrigerant cannot be routed through the expansion  
valve, restrictor and desiccant bag of certain receivers at the  
necessary rate. Therefore remove these components and re‐  
place them with adapters if applicable ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
♦ Adapters for connection of air conditioner service station and  
for bridging certain refrigerant circuit components  
⇒ page 125 .  
– Connect flushing circuit in vehicle (depending on refrigerant  
circuit) ⇒ page 125 .  
Vehicles with 2 evaporators in refrigerant circuit:  
Note  
♦ The refrigerant circuit is cleaned in 2 flushing cycles (first the  
section with the evaporator in the front heater and air condi‐  
tioning unit and then the section with the evaporator in the rear  
heater and air conditioning unit) ⇒ page 125 .  
♦ On vehicles with two evaporators, the circuit to the second  
evaporator must be separated from the circuit of the first evap‐  
orator and flushed in a separate operation ⇒ page 125 and ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐  
hicle-specific Workshop Manual).  
5. Refrigerant circuit  
107  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicles with high-voltage system (without additional air condi‐  
tioner functions, e.g. Audi A3 e-tron, Audi Q5 hybrid)  
Note  
♦ The refrigerant circuit is cleaned in 2 flushing cycles (first the  
section with the evaporator in the front heater and air condi‐  
tioning unit and then the section with the heat exchanger for  
high-voltage battery / evaporator in the battery cooling mod‐  
ule) ⇒ page 125 .  
♦ On vehicles with two evaporators or with an evaporator and a  
heat exchanger, the circuit to the second evaporator or to the  
heat exchanger must be separated from the circuit of the first  
evaporator using hand shut-off valves and flushed in a sepa‐  
rate operation ⇒ page 125 and ⇒ Heating, air conditioning;  
Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop  
Manual).  
♦ A flushing cycle currently comprises three consecutive flush‐  
ing operations (depending on the program in the air condition‐  
er service station) ⇒ page 109 .  
– Close or open the appropriate hand shut-off valves installed,  
depending on which section of the refrigerant circuit you wish  
to flush in this flushing cycle.  
– Close or open the installed electrically operated valves via the  
routine stored in the vehicle's corresponding control unit, de‐  
pending on which section of the refrigerant circuit you wish to  
flush in this flushing cycle.  
Vehicles with high-voltage system (with additional air conditioner  
functions such as heat pump operation, e.g. Audi Q7 e-tron)  
Note  
♦ The refrigerant circuit is cleaned in multiple flushing cycles  
⇒ page 125 and ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit; Cleaning air conditioner refrigerant circuit .  
♦ To perform the flushing procedure, the circuit is separated into  
multiple sections, which are then flushed in one flushing cycle  
each. The circuit is separated by activation of the installed  
electrically activated valves and via the installed manual shut-  
off valves (must be activated manually) ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant circuit; Cleaning air  
conditioner refrigerant circuit .  
♦ A flushing cycle currently comprises three consecutive flush‐  
ing operations (depending on the program in the air condition‐  
er service station) ⇒ page 109 .  
♦ The layout of the different flushing circuits for these vehicles  
is described in the corresponding vehicle-specific Workshop  
Manual ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit; Cleaning air conditioner refrigerant circuit .  
– Close or open the hand shut-off valves installed, depending  
on which section of the refrigerant circuit you wish to flush in  
this flushing cycle ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit; Cleaning air conditioner refrigerant circuit .  
108  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
– Close or open any installed electrically operated valves via the  
routine stored in the vehicle's corresponding control unit, de‐  
pending on which section of the refrigerant circuit you wish to  
flush in this flushing cycle ⇒ Vehicle diagnostic tester in “Gui‐  
ded Fault Finding” mode and ⇒ Heating, air conditioning; Rep.  
gr. 87 ; Refrigerant circuit; Cleaning air conditioner refrigerant  
circuit .  
All vehicles  
– Switch on the air conditioner service station and flush the re‐  
frigerant circuit (duration approx. 1 to 1.5 hours for one flushing  
cycle with three flushing operations).  
Note  
♦ The flushing operation is to be performed in line with the op‐  
erating instructions for the air conditioner service station ⇒  
Operating instructions for air conditioner service station .  
♦ Depending on the version of the air conditioner service station,  
3
the used oil container may only hold approx. 125 cm of re‐  
frigerant oil. If a system with a larger refrigerant oil quantity is  
to be flushed, it may be necessary to empty the used oil con‐  
tainer after the first flushing operation in a flushing cycle.  
♦ Observe the refrigerant flowing back out of the refrigerant cir‐  
cuit into the air conditioner service station. Refrigerant circuit  
cleaning has not been completed until the refrigerant flowing  
through the inspection port of the refrigerant circuit flushing kit  
into the air conditioner service station is clear and completely  
colourless.  
♦ During flushing, the entire refrigerant oil is rinsed out of the  
refrigerant circuit (with the exception of slight residue in the  
evaporator, for example; this can however be ignored).  
♦ In the case of extremely severe contamination, it may be nec‐  
essary to perform flushing twice (two flushing cycles with three  
flushing operations each).  
Sequence of flushing operation (sequence takes place automat‐  
ically in line with air conditioner service station program)  
♦ After switch-on, the flushing circuit (refrigerant circuit with con‐  
necting hoses and refrigerant circuit flushing kit) is initially  
evacuated and the refrigerant circuit checked for leaks De‐  
pending on the version of the air conditioner service station,  
manual switching to next step may be necessary ⇒ Operating  
instructions for air conditioner service station .  
♦ A specified quantity of refrigerant (e.g. 5 kg) is added to the  
evacuated refrigerant circuit via the high-pressure end of the  
air conditioner service station (in the direction opposite to the  
normal flow direction during air conditioner operation and thus  
on the low-pressure end of the vehicle refrigerant circuit) or  
refrigerant is added until the refrigerant circuit and the inspec‐  
tion ports of the refrigerant circuit flushing kit have been com‐  
pletely filled with liquid refrigerant (depending on the version  
of the air conditioner service station, the system detects that  
there has been no further inflow of refrigerant over a certain  
period for example).  
♦ Once the specified quantity of refrigerant has been added, the  
heater of the refrigerant circuit flushing kit may be switched on  
for example depending on the version of the air conditioner  
service station and the refrigerant circuit flushing kit (only if the  
refrigerant is extracted in gaseous form from the refrigerant  
circuit flushing kit).  
5. Refrigerant circuit  
109  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
♦ After the refrigerant has been extracted, the heater of the re‐  
frigerant circuit flushing kit is switched off (if fitted). Depending  
on the version, the refrigerant circuit may be briefly evacuated  
again and, following evacuation, the refrigerant oil extracted  
from the refrigerant circuit is separated by the air conditioner  
service station.  
♦ The refrigerant charging, extraction (and evacuation) process  
is repeated twice (in other words it is implemented a total of  
three times) ⇒ Operating instructions for air conditioner serv‐  
ice station .  
♦ Following extraction for the third time, the flushing circuit is  
evacuated depending on the version of the air conditioner  
service station.  
– After flushing is completed, check the sight glass(es) of the  
refrigerant circuit flushing kit. If these are contaminated, clean  
as necessary according to the operating instructions for the  
refrigerant circuit flushing kit or air conditioner service station.  
Perform flushing again as a check (duration of approx. 30 min.  
is sufficient) ⇒ Operating instructions for air conditioner serv‐  
ice station .  
– Check the pressure in the refrigerant circuit. There must not  
be any positive pressure in the refrigerant circuit (evacuate  
briefly again if necessary).  
– Detach the connections to the air conditioner service station  
from the vehicle refrigerant circuit (there must not be any pos‐  
itive pressure in the refrigerant circuit).  
– Renew the following components (vehicle-specific): restrictor  
and reservoir, expansion valve and receiver / desiccant car‐  
tridge in receiver ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
– Depending on the problem, renew air conditioner compressor  
⇒ Heating, air conditioning; Rep. gr. 87 ; Air conditioner com‐  
pressor (vehicle-specific Workshop Manual) and ⇒ Electronic  
parts catalogue , or drain off remaining refrigerant oil from air  
conditioner compressor (removed earlier) ⇒ page 272 (re‐  
newing components of refrigerant circuit) and add specified  
quantity of new refrigerant oil again ⇒ page 333 (approved  
refrigerant oils and refrigerant oil capacities).  
Note  
♦ Replacement compressors contain a certain specified quantity  
of refrigerant oil. For vehicles with two evaporators, it may be  
necessary to additionally add a certain quantity of refrigerant  
oil to the circuit ⇒ Heating, air conditioning; Rep. gr. 87 ; Re‐  
frigerant circuit (vehicle-specific Workshop Manual) and  
⇒ page 333 (approved refrigerant oils and refrigerant oil ca‐  
pacities).  
♦ If the air conditioner compressor is not supposed to be re‐  
newed, the refrigerant oil quantity in the air conditioner com‐  
pressor must be topped up in line with the specified capacity  
(pour out refrigerant oil and add the specified quantity to the  
air conditioner compressor or the refrigerant circuit again)  
⇒ page 272 (Renewing refrigerant circuit components) and  
⇒ page 333 (Approved refrigerant oils and refrigerant oil ca‐  
pacities).  
– Completely re-assemble the refrigerant circuit ⇒ Heating, air  
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
110  
Rep. gr.87 - Air conditioning system  
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Air conditioner with refrigerant R134a - Edition 11.2018  
– Evacuate and charge the refrigerant circuit as specified  
⇒ page 86 and ⇒ page 91 .  
– Start up air conditioner as specified ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit; Starting up air conditioner  
after charging refrigerant circuit (vehicle-specific Workshop  
Manual) and ⇒ page 92 .  
⇒ “5.5.1 Block diagrams for various flushing circuits”, page 111  
⇒ “5.5.3 Adapters for connecting flushing circuits”, page 125  
⇒ “5.5.2 Flushing electrically driven air conditioner compressor  
(removing refrigerant oil)”, page 119  
5.5.1  
Block diagrams for various flushing cir‐  
cuits  
Note  
♦ The arrows in the following illustrations indicate the direction  
of refrigerant flow on flushing (during flushing, the refrigerant  
flows in the direction opposite to that in air conditioner opera‐  
tion; the high-pressure end of the air conditioner service sta‐  
tion is thus connected to the low-pressure connection of the  
refrigerant circuit to the air conditioner compressor).  
♦ The block diagrams illustrate a refrigerant circuit with restrictor  
and reservoir and a refrigerant circuit with expansion valve,  
receiver and a second evaporator (optional extra for certain  
vehicles).  
♦ Depending on the design of the air conditioner service station,  
non-return valves may be fitted between the refrigerant circuit  
and the air conditioner service station (to guarantee the correct  
direction of refrigerant flow on flushing).  
Flushing circuit on vehicles with high-voltage system  
Refrigerant circuit with restrictor and reservoir ⇒ page 111  
Refrigerant circuit with expansion valve, receiver and second  
evaporator ⇒ page 115  
Vehicles with high-voltage system (without additional air condi‐  
tioner functions, e.g. Audi A3 e-tron, Audi Q5 hybrid)  
⇒ page 118  
Vehicles with high-voltage system (with additional air conditioner  
functions such as heat pump operation, e.g. Audi Q7 e-tron)  
⇒ page 118  
Refrigerant circuit with restrictor and reservoir  
Note  
On vehicles with a restrictor and reservoir, the restrictor and res‐  
ervoir are removed, and the lines unfastened to remove the  
restrictor are assembled again. The pipe connections to the res‐  
ervoir removed are connected together with two adapters and the  
filler hose - VAS 6338/31- (from the adapter set for refrigerant  
circuits - VAS 6338/1- ).  
5. Refrigerant circuit  
111  
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Air conditioner with refrigerant R134a - Edition 11.2018  
1 - Air conditioner service sta‐  
tion  
❑ With electronics and a  
flushing program, e.g.  
Air conditioner service  
station with flushing kit  
⇒ Electronic parts cata‐  
logue (Tools; Workshop  
equipment/tools; Air  
conditioning/heating).  
❑ If use is made of an air  
conditioner service sta‐  
tion with no flushing pro‐  
gram, the process is to  
be implemented man‐  
ually (evacuation, 3x  
flushing with at least 4  
kg of refrigerant each  
time, extraction of refrig‐  
erant again, evacua‐  
tion).  
2 - Refrigerant hose of air con‐  
ditioner service station  
❑ From the high-pressure  
side of the air condition‐  
er service station (gen‐  
erally red coloured) to  
the connection for the  
low-pressure side of the  
air conditioner compres‐  
sor at the refrigerant cir‐  
cuit (larger diameter)  
3 - Adapter for connection  
(low-pressure side) at refriger‐  
ant circuit  
❑ Different versions de‐  
pending on vehicle  
⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
4 - Connection (low-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
❑ At refrigerant line from air conditioner compressor to reservoir  
5 - Connection to reservoir  
❑ Different versions depending on vehicle ⇒ page 125  
❑ At refrigerant line from air conditioner compressor to reservoir  
6 - Adapter for bridging reservoir after removal  
❑ Different versions depending on vehicle ⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
7 - Filler hose for refrigerant ⇒ page 125  
❑ For example filler hose - VAS 6338/31- (from adapter set for refrigerant circuits - VAS 6338/1- )  
8 - Adapter for bridging reservoir after removal  
❑ Different versions depending on vehicle ⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
9 - Connection to reservoir  
❑ Different versions depending on vehicle ⇒ page 125  
112  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
10 - Evaporator  
11 - Fitting location for restrictor  
❑ Restrictor removed.  
❑ Removing restrictor ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual)  
12 - Bolt connection in refrigerant line  
❑ Screw back together after removing restrictor ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit  
(vehicle-specific Workshop Manual).  
13 - Condenser  
14 - Connection (high-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
15 - Adapter for connection (high-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
16 - Filler hose to refrigerant circuit flushing kit  
❑ From connection (high-pressure side) of air conditioner compressor at refrigerant circuit (smaller diam‐  
eter) to inlet of flushing kit for refrigerant circuits  
17 - Refrigerant circuit flushing kit  
❑ Different versions and different designs of the refrigerant circuit flushing kit ⇒ Electronic parts catalogue  
(Tools; Workshop equipment/tools; Air conditioning/heating).  
❑ With filter, sight glass, safety valve, heater, refrigerant vessel etc. (depending on version)  
❑ Depending on the design of the air conditioner service station and the refrigerant circuit flushing kit, a  
non-return valve may be fitted at the outlet of the refrigerant circuit flushing kit (to guarantee the correct  
direction of refrigerant flow when flushing).  
❑ Depending on the design of the refrigerant circuit flushing kit, a connection for a service coupling for  
refrigerant circuits may be fitted at the inlet (and possibly also at the outlet) of the flushing kit (instead of  
a 5/8-18 UNF external thread). If a service connection with valve is fitted at the outlet of the flushing kit,  
this valve must be fully open when the service connection is connected (if the valve is not fully open this  
creates a constriction). If there is a connection for a service coupling at the inlet of the flushing device,  
modify the inlet so that the refrigerant hose that comes from the vehicle can be directly connected (a  
service coupling and a valve in the inlet of the flushing device creates a constriction, which hinders the  
flow of refrigerant out of the vehicle into the flushing device and therefore hampers the flushing process).  
5. Refrigerant circuit  
113  
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Air conditioner with refrigerant R134a - Edition 11.2018  
Caution  
Danger of flushing kit  
outlet icing up if a valve  
is fitted but not fully open.  
I♦f a valve is fitted in the  
connection but not fully  
open, this creates a con‐  
striction which obstructs  
the flow of refrigerant in  
the flushing process and  
which may ice up due to  
excessive cooling.  
I♦f there is a service con‐  
nection with valve at the  
outlet of the flushing kit,  
this valve must be fully  
open during the flushing  
process.  
I♦f excessive cooling  
(icing-up) occurs at the  
outlet of the flushing kit  
during the flushing proc‐  
ess, abort the flushing  
process and extract the  
refrigerant from the flush‐  
ing kit and from the vehi‐  
cle via the high-pressure  
and low-pressure sides.  
Then check the valve in  
the outlet of the flushing  
kit and repair it if neces‐  
sary.  
Danger of flushing kit in‐  
let icing up in the event of  
a constriction caused by  
a service coupling and a  
valve fitted in the service  
connection.  
R♦emove the service con‐  
nection fitted to this con‐  
nection and connect the  
service hose from the ve‐  
hicle directly (without  
constriction) to the flush‐  
ing kit, using an adapter if  
necessary (this depends  
on the thread at the flush‐  
ing kit inlet).  
18 - Refrigerant hose of air conditioner service station  
❑ From low-pressure side of air conditioner service station (usually blue) to outlet of flushing kit for refrig‐  
erant circuits  
114  
Rep. gr.87 - Air conditioning system  
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Air conditioner with refrigerant R134a - Edition 11.2018  
Refrigerant circuit with expansion valve, receiver and second  
evaporator  
Note  
♦ This block diagram shows a refrigerant circuit with expansion  
valve, receiver and a second evaporator (optional extra for  
certain vehicles).  
♦ On vehicles with expansion valve and receiver, the expansion  
valve is removed and replaced with an adapter. Depending on  
the vehicle, the receiver is also removed and the pipe con‐  
nections to the receiver are connected using two adapters and  
a filler hose.  
♦ On vehicles with only one evaporator, the components from  
item “16” onwards are not fitted / are not required.  
1 - Air conditioner service sta‐  
tion  
❑ With electronics and a  
flushing program, Air  
conditioner service sta‐  
tion with flushing kit ⇒  
Electronic parts cata‐  
logue (Tools; Workshop  
equipment/tools; Air  
conditioning/heating).  
❑ If use is made of an air  
conditioner service sta‐  
tion with no flushing pro‐  
gram, the process is to  
be implemented man‐  
ually (evacuation, 3x  
flushing with at least 4  
kg of refrigerant each  
time, extraction of refrig‐  
erant again, evacua‐  
tion).  
2 - Refrigerant hose of air con‐  
ditioner service station  
❑ From the high-pressure  
side of the air condition‐  
er service station (gen‐  
erally red coloured) to  
the connection for the  
low-pressure side of the  
air conditioner compres‐  
sor at the refrigerant cir‐  
cuit (larger diameter)  
3 - Adapter for connection  
(low-pressure side) at refriger‐  
ant circuit  
❑ Different versions de‐  
pending on vehicle  
⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
4 - Connection (low-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
5 - Adapter for removed expansion valve  
❑ Different versions depending on vehicle ⇒ page 125  
5. Refrigerant circuit  
115  
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❑ From adapter set for refrigerant circuits - VAS 6338/1-  
6 - Evaporator  
7 - Connection to receiver  
❑ Different versions depending on vehicle ⇒ page 125  
❑ Not fitted on vehicles with a desiccant cartridge in the receiver at the condenser or with a receiver installed  
in the condenser ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop  
Manual).  
8 - Adapter for bridging removed receiver  
❑ Not necessary on all vehicles  
❑ Different versions depending on vehicle ⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
9 - Filler hose for refrigerant ⇒ page 125  
❑ For example filler hose - VAS 6338/31- (from adapter set for refrigerant circuits - VAS 6338/1- )  
10 - Condenser  
❑ If a receiver with desiccant cartridge is fitted at the condenser, the desiccant cartridge must be removed  
(seal receiver at or in condenser again following removal) ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual).  
❑ If the receiver is attached directly to the condenser, flush the system before removing and renewing the  
receiver ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Manual).  
Note  
On certain vehicles, the receiver is  
integrated into the condenser, and  
the desiccant cartridge cannot be  
renewed separately or is not availa‐  
ble separately. On these vehicles,  
renew the condenser together with  
the receiver / desiccant cartridge af‐  
ter flushing ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant  
circuit (vehicle-specific Workshop  
Manual) and ⇒ Electronic parts  
catalogue .  
11 - Connection (high-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
12 - Adapter for connection (high-pressure side) at refrigerant circuit  
❑ Different versions depending on vehicle ⇒ page 125  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
13 - Filler hose to refrigerant circuit flushing kit  
❑ From connection (high-pressure side) of air conditioner compressor at refrigerant circuit (smaller diam‐  
eter) to inlet of flushing kit for refrigerant circuits  
14 - Refrigerant circuit flushing kit  
❑ Different versions and different designs of the refrigerant circuit flushing kit ⇒ Electronic parts catalogue  
(Tools; Workshop equipment/tools; Air conditioning/heating).  
❑ With filter, sight glass, safety valve, heater, refrigerant vessel etc. (depending on version)  
❑ Depending on the design of the air conditioner service station and the refrigerant circuit flushing kit, a  
non-return valve may be fitted at the outlet of the refrigerant circuit flushing kit (to guarantee the correct  
direction of refrigerant flow when flushing).  
❑ Depending on the design of the refrigerant circuit flushing kit, a connection for a service coupling for  
refrigerant circuits may be fitted at the inlet (and possibly also at the outlet) of the flushing kit (instead of  
a 5/8-18 UNF external thread). If a service connection with valve is fitted at the outlet of the flushing kit,  
this valve must be fully open when the service connection is connected (if the valve is not fully open this  
creates a constriction). If there is a connection for a service coupling at the inlet of the flushing device,  
modify the inlet so that the refrigerant hose that comes from the vehicle can be directly connected (a  
116  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
service coupling and a valve in the inlet of the flushing device creates a constriction, which hinders the  
flow of refrigerant out of the vehicle into the flushing device and therefore hampers the flushing process).  
Caution  
Danger of flushing kit  
outlet icing up if a valve  
is fitted but not fully open.  
I♦f a valve is fitted in the  
connection but not fully  
open, this creates a con‐  
striction which obstructs  
the flow of refrigerant in  
the flushing process and  
which may ice up due to  
excessive cooling.  
I♦f there is a service con‐  
nection with valve at the  
outlet of the flushing kit,  
this valve must be fully  
open during the flushing  
process.  
I♦f excessive cooling  
(icing-up) occurs at the  
outlet of the flushing kit  
during the flushing proc‐  
ess, abort the flushing  
process and extract the  
refrigerant from the flush‐  
ing kit and from the vehi‐  
cle via the high-pressure  
and low-pressure sides.  
Then check the valve in  
the outlet of the flushing  
kit and repair it if neces‐  
sary.  
Danger of flushing kit in‐  
let icing up in the event of  
a constriction caused by  
a service coupling and a  
valve fitted in the service  
connection.  
R♦emove the service con‐  
nection fitted to this con‐  
nection and connect the  
service hose from the ve‐  
hicle directly (without  
constriction) to the flush‐  
ing kit, using an adapter if  
necessary (this depends  
on the thread at the flush‐  
ing kit inlet).  
15 - Refrigerant hose of air conditioner service station  
❑ From low-pressure side of air conditioner service station (usually blue) to outlet of flushing kit for refrig‐  
erant circuits  
16 - Adapter for sealing outlet to second evaporator  
❑ Only required for certain vehicles with “second evaporator” as optional extra  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
17 - Adapter for sealing outlet to second evaporator  
❑ Only required for certain vehicles with “second evaporator” as optional extra  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
5. Refrigerant circuit  
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18 - Connection (low-pressure side) at refrigerant circuit to second evaporator  
❑ Different versions depending on vehicle ⇒ page 125  
❑ Only fitted on certain vehicles with “second evaporator” as optional extra  
19 - Connection (high-pressure side) at refrigerant circuit to second evaporator  
❑ Different versions depending on vehicle ⇒ page 125  
❑ Only fitted on certain vehicles with “second evaporator” as optional extra  
20 - Adapter for expansion valve (removed) at second evaporator  
❑ Different versions depending on vehicle ⇒ page 125  
❑ Only required for certain vehicles with “second evaporator” as optional extra  
❑ From adapter set for refrigerant circuits - VAS 6338/1-  
21 - Second evaporator  
❑ Only fitted on certain vehicles with “second evaporator” as optional extra  
Vehicles with high-voltage system (without additional air condi‐  
tioner functions, e.g. Audi A3 e-tron, Audi Q5 hybrid)  
Note  
♦ The refrigerant circuit is cleaned in 2 flushing cycles (first the  
section with the evaporator in the front heater and air condi‐  
tioning unit and then the section with the heat exchanger for  
high-voltage battery / evaporator in the battery cooling mod‐  
ule) ⇒ page 125 .  
♦ On vehicles with two evaporators or with an evaporator and a  
heat exchanger, the circuit to the second evaporator or to the  
heat exchanger must be separated from the circuit of the first  
evaporator using hand shut-off valves and flushed in a sepa‐  
rate operation ⇒ page 125 and ⇒ Heating, air conditioning;  
Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop  
Manual).  
♦ The layout of the different flushing circuits for these vehicles  
is similar to the layout on a vehicle with 2 evaporators  
⇒ page 115 .  
Vehicles with high-voltage system (with additional air conditioner  
functions such as heat pump operation, e.g. Audi Q7 e-tron)  
Note  
♦ The refrigerant circuit is cleaned in multiple flushing cycles  
⇒ page 125 and ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit; Cleaning air conditioner refrigerant circuit .  
♦ To perform the flushing procedure, the circuit is separated into  
multiple sections, which are then flushed in one flushing cycle  
each. The circuit is separated by activation of the installed  
electrically activated valves and via the installed manual shut-  
off valves (must be activated manually) ⇒ Heating, air condi‐  
tioning; Rep. gr. 87 ; Refrigerant circuit; Cleaning air  
conditioner refrigerant circuit .  
♦ The layout of the different flushing circuits for these vehicles  
is described in the corresponding vehicle-specific Workshop  
Manual ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit; Cleaning air conditioner refrigerant circuit .  
118  
Rep. gr.87 - Air conditioning system  
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5.5.2  
Flushing electrically driven air condition‐  
er compressor (removing refrigerant oil)  
Vehicles with high-voltage system (hybrid vehicles)  
High voltage! Danger to life!  
The voltage levels in the high-voltage system constitute a safety  
hazard. Danger of severe or fatal injuries from electric shock.  
– Persons with life-sustaining or other electronic medical devi‐  
ces in or on their body must not perform any work on the high-  
voltage system. Such medical devices include internal anal‐  
gesic pumps, implanted defibrillators, pacemakers, insulin  
pumps and hearing aids.  
– The high-voltage system must be de-energised by a suitably  
qualified person.  
Risk of injury - engine may start unexpectedly  
It is difficult to determine whether the drive system of an electric  
vehicle or hybrid vehicle is active. Moving parts can trap or draw  
in parts of the body.  
– Switch off ignition.  
– Place ignition key outside vehicle.  
Risk of damage to high-voltage wiring  
Incorrect handling may result in damage to the insulation of high-  
voltage wires or high-voltage connectors.  
– Never use high-voltage wiring or high-voltage connectors as  
a support.  
– Never prop tools against high-voltage wiring or high-voltage  
connectors.  
– Never bend or kink high-voltage wiring.  
– Pay attention to coding when connecting high-voltage con‐  
nections.  
♦ For all work on vehicles with high-voltage system, note addi‐  
tional warnings for working on such vehicles  
⇒ “1 Warning instructions when working on vehicles with high-  
voltage system”, page 1 .  
♦ If work near high-voltage system components is necessary,  
perform a visual check of the high-voltage components and  
wires to check for damage ⇒ page 2 .  
♦ If work on high-voltage system components is necessary, de-  
energise high-voltage system ⇒ Rep. gr. 93 ; De-energising  
high-voltage system or ⇒ Electrical system; Rep. gr. 93 ; De-  
energising high-voltage system .  
– To minimise the number of automatic engine starts when the  
vehicle's drive system is active during test and measurement  
work, charge the vehicle batteries e.g. with the battery  
charger 60A - VAS 5904- in battery standby mode ⇒ Electrical  
system; General information; Rep. gr. 27 ; Battery; Charging  
5. Refrigerant circuit  
119  
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Air conditioner with refrigerant R134a - Edition 11.2018  
battery and ⇒ Electrical system; Rep. gr. 93 ; General warning  
instructions for work on the high-voltage system .  
– For test and measurement work that requires the vehicle's  
drive system to be active (READY) or the ignition to be switch‐  
ed on, move the selector lever to position “P”, activate the  
parking brake and take care to keep well clear of the engine  
when it is running. Set up any tools needed so that they cannot  
come into contact with moving parts.  
Note  
♦ Move the selector lever to position “P” and activate the parking  
brake before performing test and measurement work for which  
the ignition must be switched on but where the vehicle's drive  
system does not need to be active.  
♦ The status of the drive system (READY) is shown by the con‐  
trol unit in dash panel insert - J285- via the “power meter” ⇒  
Owner's Manual .  
♦ Activating and deactivating drive system ⇒ Owner's Manual  
(note display of control unit in dash panel insert - J285- ).  
Notes on removing refrigerant oil from the electrically driven air  
conditioner compressor (by flushing)  
Note  
♦ With the electrically driven air conditioner compressor, the re‐  
frigerant oil cannot be poured out in the same way and to the  
same extent as with the mechanically driven air conditioner  
compressor. There is no oil drain plug and the internal struc‐  
ture means that, depending on the version, it may only be  
possible to pour out a small amount of refrigerant oil (or even  
none at all). Depending on the version of the air conditioner  
3
compressor and how it is stored, approx. 30 to 80 cm of re‐  
frigerant oil may remain in the air conditioner compressor after  
the pouring operation (the electric air conditioner compressor  
cannot be turned). Depending on the problem, the air condi‐  
tioner compressor must therefore be flushed in order to re‐  
move the refrigerant oil and determine the quantity of  
refrigerant oil in the air conditioner compressor  
⇒ “9.1.3 Renewing air conditioner compressor without having  
to clean refrigerant circuit”, page 277 .  
♦ On the electrically driven air conditioner compressor, the re‐  
frigerant oil can be removed by flushing in the flow direction  
(flushing in the opposite direction is not possible on account  
of the built-in valves).  
♦ For the flushing procedure, position the air conditioner com‐  
pressor so that t.he connection for the refrigerant line on the  
high-pressure side is as low down as possible.  
♦ The electrically driven air conditioner compressor must be  
flushed if there is a possibility that there is too much refrigerant  
oil in the refrigerant circuit or in order to remove contaminated  
(moisture-laden) refrigerant oil from the air conditioner com‐  
pressor. In these cases, the refrigerant circuit must also be  
flushed to clean it and allow the correct quantity of refrigerant  
oil for the refrigerant circuit to be set once again  
⇒ “10.2.2 Refrigerant oil capacities”, page 337 .  
♦ If an electrically driven air conditioner compressor is renewed,  
it is not always necessary to flush the refrigerant circuit. The  
quantity of refrigerant oil in the removed air conditioner com‐  
pressor can be determined by flushing the removed air con‐  
120  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
ditioner compressor. The quantity of refrigerant oil in the new  
air conditioner compressor must then be matched to the quan‐  
tity flushed out of the old air conditioner compressor (plus 10  
3
cm ) by pouring out the excess  
⇒ “9.1.3 Renewing air conditioner compressor without having  
to clean refrigerant circuit”, page 277 .  
♦ To determine the quantity of refrigerant oil in the removed air  
conditioner compressor, the refrigerant oil must be flushed out  
of the air conditioner compressor to be removed and the flush‐  
ed quantity measured (empty the vessels for old oil provided  
at the air conditioner service station before flushing the air  
conditioner compressor). Refrigerant oil must then be poured  
out of the new air conditioner compressor until the quantity  
remaining in the new air conditioner compressor corresponds  
to the quantity of refrigerant oil flushed out from the old air  
3
conditioner compressor (plus 10 cm ). Dispose of refrigerant  
oil flushed out of the defective air conditioner compressor and  
poured out of the new air conditioner compressor ⇒ Audi  
ServiceNet, HSO Environmental Protection (observe local  
regulations).  
♦ The air conditioner compressor to be newly installed must be  
flushed if the quantity of refrigerant oil that can be poured out  
of it is insufficient. After flushing, the air conditioner compres‐  
sor to be installed must be filled up with the same quantity of  
new refrigerant oil as was flushed out of the old air conditioner.  
3
Example: If 120 cm of refrigerant oil was flushed out of the  
removed air conditioner compressor, and the new compressor  
3
contains 200 cm (see type plate and  
3
⇒ “10.2.2 Refrigerant oil capacities”, page 337 ), 110 cm (120  
3
3
cm minus 10 cm ) must be poured out of the new compressor  
so that the refrigerant circuit contains the correct quantity of  
refrigerant oil after the new compressor is installed. If the re‐  
quired quantity of refrigerant oil cannot be poured out, then the  
air conditioner compressor to be newly installed must also be  
flushed. The new air conditioner compressor must then be fil‐  
led up with the same quantity of refrigerant oil as was previ‐  
ously flushed out of the old air conditioner compressor.  
Flushing the electrically driven air conditioner compressor  
Note  
Depending on the air conditioner compressor, a new compressor  
can be filled with a larger quantity of refrigerant oil (e.g. 290  
3
cm on the Audi Q7 e-tron); refer to the manufacturer's label on  
the air conditioner compressor and  
⇒ “10.2.2 Refrigerant oil capacities”, page 337 ). Before flushing  
3
new air conditioner compressors filled with more than 100 cm ,  
pour out as much refrigerant oil as possible. Reason: Depending  
on the version of the air conditioner service station, the quantity  
of oil which can be separated in one operation may be limited (e.g.  
3
150 cm ). Further notes ⇒ Item 5 (page 122)  
5. Refrigerant circuit  
121  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
1 - Air conditioner service sta‐  
tion  
❑ With electronics and a  
flushing program, Air  
conditioner service sta‐  
tion with flushing kit ⇒  
Electronic parts cata‐  
logue (Tools; Workshop  
equipment/tools; Air  
conditioning/heating).  
❑ If use is made of an air  
conditioner service sta‐  
tion with no flushing pro‐  
gram, the process is to  
be implemented man‐  
ually (evacuation, 3x  
flushing with at least  
2 kg of refrigerant each  
time, extraction of refrig‐  
erant again, evacua‐  
tion).  
2 - Refrigerant hose of air con‐  
ditioner service station  
❑ From the high-pressure  
side of the air condition‐  
er service station (gen‐  
erally red coloured) to  
the connection for the  
low-pressure side of the  
air conditioner compres‐  
sor at the refrigerant cir‐  
cuit (larger diameter)  
3 - Adapter for connection  
(low-pressure side) to air con‐  
ditioner compressor  
❑ Different versions de‐  
pending on vehicle  
⇒ page 125  
❑ Use the adapter from the VW/Audi passenger vehicle adapter set - VAS 6338/1- (here adapter - VAS  
6338/41- ).  
4 - Refrigerant line  
❑ For connecting air conditioner compressor to adapter ⇒ Item 3 (page 122)  
Note  
♦ A refrigerant line must only be  
used if an adapter - VAS  
6338/41- is not available.  
♦ If an adapter - VAS 6338/41- for  
setting up the flushing circuit is  
not available, remove e.g. the re‐  
frigerant line to the condenser  
from the vehicle (or use a refrig‐  
erant line with part number 7L6  
820 744 AD) ⇒ Electronic parts  
catalogue .  
5 - Electrically driven air conditioner compressor  
❑ The air conditioner compressor is flushed in flow direction (from the low-pressure end inlet to the high-  
pressure end outlet)  
❑ To flush as much refrigerant oil as possible out of the air conditioner compressor, the compressor should  
be positioned with the high-pressure end outlet as low down as possible when flushing  
122  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Caution  
Danger of impairing op‐  
eration of the air condi‐  
tioner service station  
(depending on version  
and quantity of refriger‐  
ant oil in the air condi‐  
tioner compressor).  
D♦epending on the ver‐  
sion of the air conditioner  
service station, the quan‐  
tity of oil which can be  
separated in one opera‐  
tion may be limited (e.g.  
3
100 cm ). Observe the  
operating instructions  
and technical product de‐  
scription for the air condi‐  
tioner service station.  
D♦epending on the air  
conditioner compressor,  
a new compressor can  
be filled with a larger  
quantity of refrigerant oil  
3
(e.g. 290 cm on the Audi  
Q7 e-tron)  
⇒ “10.2.2 Refrigerant oil  
capacities”, page 337  
and  
⇒ “9.1.3 Renewing air  
conditioner compressor  
without having to clean  
refrigerant circuit”,  
page 277 .  
B♦efore flushing new air  
conditioner compressors  
filled with more than 150  
3
cm , pour out as much  
refrigerant oil as possible  
(into a clean container,  
via the high-pressure and  
low-pressure connec‐  
tion). This prevents the  
oil separator of your air  
conditioner service sta‐  
tion from being overfilled  
during the flushing proc‐  
ess.  
T♦hen flush any remaining  
refrigerant oil out of the  
air conditioner compres‐  
sor.  
Note  
If you pour the clean refrigerant oil  
out of a new air conditioner com‐  
pressor into a clean container and  
then seal the container so that it is  
air-tight, you can re-use this oil to  
adjust the quantity of refrigerant oil  
in the refrigerant circuit.  
5. Refrigerant circuit  
123  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
6 - Refrigerant line  
❑ For connecting air conditioner compressor to adapter ⇒ Item 7 (page 124)  
Note  
♦ A refrigerant line must only be  
used if an adapter - VAS  
6338/40- is not available.  
♦ If an adapter - VAS 6338/40- for  
setting up the flushing circuit is  
not available, use e.g. a refriger‐  
ant line with part number  
7L6 820 721 BF or  
4G0 260 701 AB ⇒ Electronic  
parts catalogue .  
7 - Adapter for connecting (high-pressure side) to air conditioner compressor  
❑ Different versions depending on vehicle ⇒ page 125  
❑ Use the adapter from the VW/Audi passenger vehicle adapter set - VAS 6338/1- (here adapter - VAS  
6338/40- ).  
8 - Filler hose to refrigerant circuit flushing kit  
❑ From connection (high-pressure side) of air conditioner compressor at refrigerant circuit (smaller diam‐  
eter) to inlet of flushing kit for refrigerant circuits  
9 - Refrigerant circuit flushing kit  
❑ Different versions and different designs of the refrigerant circuit flushing kit ⇒ Electronic parts catalogue  
(Tools; Workshop equipment/tools; Air conditioning/heating).  
❑ With filter, sight glass, safety valve, heater, refrigerant vessel etc. (depending on version)  
❑ Depending on the design of the air conditioner service station and the refrigerant circuit flushing kit, a  
non-return valve may be fitted at the outlet of the refrigerant circuit flushing kit (to guarantee the correct  
direction of refrigerant flow when flushing).  
❑ Depending on the design of the refrigerant circuit flushing kit, a connection for a service coupling for  
refrigerant circuits may be fitted at the inlet (and possibly also at the outlet) of the flushing kit (instead of  
a 5/8-18 UNF external thread). If a service connection with valve is fitted at the outlet of the flushing kit,  
this valve must be fully open when the service connection is connected (if the valve is not fully open this  
creates a constriction). If there is a connection for a service coupling at the inlet of the flushing device,  
modify the inlet so that the refrigerant hose that comes from the vehicle can be directly connected (a  
service coupling and a valve in the inlet of the flushing device creates a constriction, which hinders the  
flow of refrigerant out of the vehicle into the flushing device and therefore hampers the flushing process).  
124  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Caution  
Danger of flushing kit  
outlet icing up if a valve  
is fitted but not fully open.  
I♦f a valve is fitted in the  
connection but not fully  
open, this creates a con‐  
striction which obstructs  
the flow of refrigerant in  
the flushing process and  
which may ice up due to  
excessive cooling.  
I♦f there is a service con‐  
nection with valve at the  
outlet of the flushing kit,  
this valve must be fully  
open during the flushing  
process.  
I♦f excessive cooling  
(icing-up) occurs at the  
outlet of the flushing kit  
during the flushing proc‐  
ess, abort the flushing  
process and extract the  
refrigerant from the flush‐  
ing kit and from the vehi‐  
cle via the high-pressure  
and low-pressure sides.  
Then check the valve in  
the outlet of the flushing  
kit and repair it if neces‐  
sary.  
Danger of flushing kit in‐  
let icing up in the event of  
a constriction caused by  
a service coupling and a  
valve fitted in the service  
connection.  
R♦emove the service con‐  
nection fitted to this con‐  
nection and connect the  
service hose from the ve‐  
hicle directly (without  
constriction) to the flush‐  
ing kit, using an adapter if  
necessary (this depends  
on the thread at the flush‐  
ing kit inlet).  
10 - Refrigerant hose of air conditioner service station  
❑ From low-pressure side of air conditioner service station (usually blue) to outlet of flushing kit for refrig‐  
erant circuits  
5.5.3  
Adapters for connecting flushing circuits  
♦ The following table lists the various adapters required for con‐  
necting the air conditioner service station to the refrigerant  
circuit for flushing and for bridging the removed receiver or  
reservoir and expansion valve (vehicle-specific).  
♦ Use a filler hose with 5/8 -18 UNF connections (short version  
e.g. filler hose - VAS 6338/31- ) to connect the two adapters  
5. Refrigerant circuit  
125  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
fitted instead of the reservoir or receiver removed earlier (con‐  
tained in adapter set for refrigerant circuits - VAS 6338/1- ).  
♦ If a flushed refrigerant circuit is not supposed to be re-assem‐  
bled immediately after flushing, leave the adapters in place at  
the connections and seal the connections at the adapters with  
the caps - VAS 6338/30- (from the adapter set for refrigerant  
circuits - VAS 6338/1- ).  
♦ Depending on the version of the air conditioner compressor  
and the production period, different connection and sealing  
methods may have been used for the refrigerant circuit ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐  
hicle-specific Workshop Manual).  
♦ The logo of the compressor manufacturer “Zexel” attached to  
the air conditioner compressor was modified from “Zexel” to  
“Valeo” from year of production 2006 onwards (change in  
manufacturer's name).  
Block or screw connections  
– Screw connection -A-  
– Block connection -B-  
Block connections with different types of seal  
– Block connection with radial seal -A- (with plastic or metal  
guide -B-)  
– Block connection with axial seal -C-  
Assembling flushing circuit  
Audi A1 (8X_) and Audi A2  
Audi A1 (GB)  
Audi Q2, Audi A3, Audi Q3 and Audi TT  
Audi A3 e-tron  
⇒ page 127  
⇒ page 128  
⇒ page 128  
⇒ page 130  
Audi 80, Audi 90, Audi Coupé, Audi Cabriolet and Audi ⇒ page 133  
A4  
Audi A5 Coupé and Sportback, Audi Q5, Audi A5 Cab‐ ⇒ page 136  
riolet  
Audi Q5 hybrid  
⇒ page 138  
Audi 100, Audi A6 (4A_, 4B_ and 4F_), Audi allroad ⇒ page 142  
and Audi V8  
Audi A6 (4G_ or 4X_ for China), Audi A7 (4G_ or 4X_ ⇒ page 143  
for China)  
Audi A6 hybrid, Audi A6 e-tron  
⇒ page 144  
126  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Assembling flushing circuit  
Audi A6 (4A_ or 48_ for China), Audi A7 (4K_)  
Audi A8 (4D_, 4E_ and 4H_)  
Audi A8 hybrid (4H_)  
Audi A8 (4N)  
⇒ page 148  
⇒ page 149  
⇒ page 152  
⇒ page 157  
⇒ page 159  
⇒ page 161  
⇒ page 163  
⇒ page 165  
⇒ page 166  
⇒ page 168  
Audi Q7 (4L_)  
Audi Q7 (4M_), Audi Q8 (4M_)  
Audi Q7 e-tron (4M_)  
Audi R8 (42_)  
Audi R8 (4S_)  
Audi e-tron (GE_) 2019 ▶  
Audi A1 (8X_) 2011 ► and Audi A2  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A1 – Compressor Different versions  
Expansion  
(8X_)  
manufacturer – Version 1 (receiver valve re‐  
2011 ►  
“Denso”,  
“Sanden” or  
“Delphi/  
integrated in con‐ moved and  
denser): No adapt‐ adapter -  
er required; the  
VAS  
Mahle”  
desiccant bag is re‐ 6338/34-  
moved from the re‐ or adapter  
ceiver at the con‐ - VAS  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
denser and the  
6338/39-  
opening is sealed (see notes  
again for flushing. below) fit‐  
ted (or old  
6338/12-  
♦ High-pres‐  
sure side:  
– Version 2 (receiver removed  
attached to con‐  
expansion  
adapter -  
denser): No adapt‐ valve dril‐  
er required; the re‐ led open  
ceiver is left instal‐ for flushing  
led (renewed after and re-in‐  
VAS 6338/3-  
or adapter -  
VAS 6338/2-  
(depending  
on layout of  
air condition‐  
er compres‐  
sor and corre‐  
sponding re‐  
frigerant line)  
flushing).  
stalled)  
⇒
page 105  
Audi A2 – Compressor Reservoir  
- Restrictor  
(8Z_)  
manufacturer – Screw connection removed,  
2001 ►  
“Denso”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
at inlet Adapter -  
VAS 6338/9-  
pipe con‐  
nections  
re-assem‐  
bled  
– Block connection  
with axial seal at  
outlet Adapter -  
VAS 6338/10-  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/2-  
5. Refrigerant circuit  
127  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ Depending on the version of the condenser, the receiver may  
be attached to or integrated into the condenser on the Audi  
A1/S1. The integrated receiver is fitted with a desiccant car‐  
tridge which can be renewed separately. If an attached re‐  
ceiver (introduction not yet finalised) is fitted, it must be  
renewed after flushing ⇒ Electronic parts catalogue and ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit (ve‐  
hicle-specific Workshop Manual).  
♦ Different versions of air conditioning unit (different heat ex‐  
changer, seals, expansion valve etc.), depending on produc‐  
tion period and vehicle identification number of Audi A1/S1 ⇒  
Electronic parts catalogue . Vehicles with type codes “8X1”  
and “8XA” in the vehicle identification number are fitted with  
an expansion valve on which the two refrigerant lines are se‐  
cured at top ( adapter - VAS 6338/34- is compatible). Vehicles  
with the type codes “8XF” and “8XK” in the vehicle identifica‐  
tion number are fitted with an expansion valve with two refrig‐  
erant lines bolted on at the bottom; the adapter - VAS 6338/39-  
is compatible here ⇒ Heating, air conditioner; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual).  
Audi Q2, Audi A3, Audi Q3, Audi TT, Audi A1 (GB) 2019 ►  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A3 – Compressor Receiver  
Expansion  
(8L_)  
manufacturer – Block connections valve re‐  
1997 ►  
Audi TT  
(8N_)  
“Sanden” or  
“Zexel / Va‐  
leo”  
with axial seal at in‐ moved and  
let and outlet  
Adapter - VAS  
6338/2- (2x re‐  
quired)  
Adapter -  
VAS  
1999 ► ♦ Low-pres‐  
sure side:  
6338/19-  
fitted (or  
drilled-  
adapter -  
VAS 6338/7-  
open ex‐  
pansion  
valve e.g.  
6N0 820  
679 C fit‐  
ted  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/2-  
⇒
page 105 )  
128  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A3 – Compressor Receiver (different ver‐ Expansion  
(8P_)  
manufacturer sions)  
valve re‐  
2004 ►  
Audi TT  
(8J_)  
for Audi A3 / – Adapter not re‐  
moved and  
Audi Q3:  
quired, receiver re‐ adapter -  
“Sanden”,  
“Denso”,  
mains in position  
VAS  
2007 ►  
Audi Q3  
(8U_ /  
84_)  
6338/18-  
“Delphi/  
– Depending on the (or drilled-  
version of the con‐ out expan‐  
denser, it may be sion valve  
Mahle” or  
“Zexel/Valeo”  
2012 ► – Compressor  
manufacturer  
for Audi TT:  
“Denso”,  
necessary to re‐  
e.g.  
move the desiccant 1K0 820 6  
cartridge from the 79 X) in‐  
receiver on the con‐ stalled  
“Sanden” or  
“Delphi/  
denser before  
⇒
flushing and to seal page 105  
the opening again  
(see note).  
Mahle”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
Audi Q2 – Compressor Receiver (different ver‐ Expansion  
(GA_),  
Audi A3  
(8V_/  
manufacturer sions)  
valve re‐  
moved and  
“Denso” or  
“Sanden”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
– No adapter re‐  
quired; receiver is adapter -  
not removed (or is VAS  
integrated in con‐ 6338/38-  
85_)  
2013 ►  
Audi TT  
(FV_)  
denser).  
(or drilled-  
out expan‐  
2015 ►  
Audi Q2  
(G1_)  
6338/12-  
– Depending on the sion valve  
version of the con‐ e.g.  
♦ High-pres‐  
sure side:  
denser, it may be 5Q0 820 6  
2019►  
Audi Q3  
(F3_)  
necessary to re‐  
79 X) in‐  
adapter -  
move the desiccant stalled  
VAS 6338/3-  
cartridge from the  
⇒
2019 ►  
Audi A1  
(GB)  
receiver on the con‐ page 105  
denser before  
♦
flushing and to seal  
the opening again  
(see note).  
2019 ►  
5. Refrigerant circuit  
129  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ The design of the receiver on the Audi A3, Audi Q3 and Audi  
TT differs depending on the condenser manufacturer. On the  
Audi TT (8J_) 2007 ► with a 5-cyl. engine for example, a dif‐  
ferent condenser version is installed than in vehicles with 4-  
cyl. or 6-cyl. engines. This condenser e.g. has an integrated  
receiver. The integrated receiver contains a desiccant car‐  
tridge which is currently not always available as a replacement  
part. Therefore it may be necessary to renew the complete  
condenser after eliminating any faults on vehicles fitted with  
this condenser ⇒ Electronic parts catalogue and ⇒ Heating,  
air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-spe‐  
cific Workshop Manual).  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
Audi A3 e-tron  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A3 – Compressor Receiver (different ver‐ ♦ Expansion  
(8V_/  
85_)  
manufacturer sions)  
valve removed  
and adapter -  
VAS 6338/38-  
(or drilled-out  
expansion  
“Denso” or  
“Sanden”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
– No adapter re‐  
2013 ►  
quired; receiver is  
not removed (or is  
integrated in con‐  
denser).  
valve e.g.  
– Depending on the  
version of the con‐  
denser, it may be  
necessary to re‐  
move the desiccant  
cartridge from the  
receiver on the con‐  
denser before  
5Q0 820 679 X)  
installed  
6338/12-  
⇒ page 105  
♦ High-pres‐  
sure side:  
♦ Shut-off valves -  
N541- and -  
adapter -  
VAS 6338/3-  
N542- removed  
and two shut-off  
valves - VAS  
flushing and to seal  
the opening again  
(see note).  
6338/42- instal‐  
led instead (see  
notes below)  
♦ Shut-off valve -  
VAS 6338/42-  
Renew shut-off  
valves -N541-  
and -N542- af‐  
ter flushing.  
♦ Restrictor in re‐  
frigerant line to  
heat exchanger  
for high-voltage  
battery re‐  
moved or refrig‐  
erant line drilled  
open (see notes  
below) Renew  
after flushing  
130  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Adapters / lines  
required for con‐  
nections on elec‐  
trically driven air  
conditioner com‐  
pressor (for  
♦ On the  
electri‐  
cally  
driven  
air con‐  
ditioner  
com‐  
flushing air con‐  
ditioner com‐  
press‐  
or, the  
refrig‐  
erant oil  
is to be  
re‐  
pressor)  
⇒ page 121  
(Flushing the  
electrically driv‐  
en air condition‐  
er compressor)  
moved  
by  
flushing  
in the  
direc‐  
tion of  
flow (it  
is not  
possi‐  
ble to  
flush in  
the op‐  
posite  
direc‐  
tion due  
to the  
valves  
instal‐  
led)  
♦ For the  
flushing  
proce‐  
dure,  
position  
the air  
condi‐  
tioner  
com‐  
pressor  
so that  
the  
con‐  
nection  
for the  
refrig‐  
erant  
line on  
the  
high-  
pres‐  
sure  
side is  
as low  
down  
as pos‐  
sible  
5. Refrigerant circuit  
131  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ The refrigerant circuit on the Audi A3 e-tron is flushed in 2  
sections. In the first flushing cycle, the adapter installed for  
shut-off valve -N541- is opened and the adapter installed for  
shut-off valve -N542- is closed. The refrigerant circuit is flush‐  
ed with the evaporator in the conditioning unit. In the second  
flushing cycle, the adapter installed for shut-off valve -N541-  
is closed and the adapter installed for shut-off valve -N542- is  
opened. The refrigerant circuit is flushed with the evaporator  
in the heat exchanger for high-voltage battery ⇒ Heating, air  
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
♦ The illustration shows a refrigerant line -A- with a permanently  
installed restrictor -B- (without strainer). This refrigerant line  
must be drilled open (5.0 mm) with a suitable drill bit in order  
to flush the refrigerant circuit (remove restrictor if fitted) and  
must be cleaned before it is installed in the flushing circuit.  
After flushing, refrigerant line/inserted restrictor must be re‐  
newed ⇒ Electronic parts catalogue .  
♦ The diameter of the restrictor hole -B- is approx. 0.7 mm. De‐  
pending on the version of the refrigerant line, the restrictor is  
either only inserted or fixed in position in the refrigerant line. If  
it is inserted, there may be a strainer for separating float ele‐  
ments, which may block off the restrictor hole.  
♦ The design of the receiver on the Audi A3 differs depending  
on the manufacturer of the condenser. This condenser e.g.  
has an integrated receiver. The integrated receiver contains a  
desiccant cartridge which is currently not always available as  
a replacement part. Therefore it may be necessary to renew  
the complete condenser after eliminating any faults on vehi‐  
cles fitted with this condenser ⇒ Electronic parts catalogue  
and ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant cir‐  
cuit (vehicle-specific Workshop Manual).  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
132  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi 80, Audi 90, Audi Coupé, Audi Cabriolet and Audi A4  
Vehicle Adapters re‐ Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi 80 – Compressor Reservoir with differ‐ - Restrictor  
(8A_/  
manufacturer ent connection ver‐  
removed,  
pipe con‐  
nections  
re-assem‐  
bled  
8C_),  
“Zexel /  
sions  
Audi  
Valeo” (screw ♦ Version 1  
connections)  
Coupé  
(8B_),  
Audi  
– Screw connection  
♦ Low-pres‐  
sure side:  
at inlet Adapter -  
VAS 6338/9-  
Cabrio‐  
let (8G_)  
► 2002  
Audi A4  
(8D_)  
adapter -  
VAG 1785/8-  
– Screw connection  
at outlet Adapter -  
VAG 1785/8-  
♦ High-pres‐  
sure side:  
adapter -  
1995►  
VAG 1785/7-  
♦ Version 2  
– Compressor  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
and axial  
– Screw connection  
at inlet Adapter -  
VAS 6338/9-  
– Block connection  
with axial seal at  
outlet Adapter -  
VAS 6338/10-  
seal)  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/2-  
Audi A4 – Compressor Reservoir with differ‐ - Restrictor  
(8E_)  
manufacturer ent connection ver‐  
“Denso” (bloc sions  
removed,  
pipe con‐  
nections  
re-assem‐  
bled  
2001 ►  
Audi A4  
Cabrio‐  
let (8H_)  
2003 ►  
k connections ♦ Version 1  
with radial  
– Block connections  
with axial seal at in‐  
let and outlet  
and axial  
seal)  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
♦ Adapter - VAS  
6338/10- (2x re‐  
quired)  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/2-  
5. Refrigerant circuit  
133  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
– Compressor ♦ Version 2  
manufacturer  
– Block connections  
“Denso” (bloc  
k connections  
with radial  
seal) ⇒ Heat‐  
ing, air condi‐  
tioner; Rep.  
gr. 87 ; Re‐  
frigerant cir‐  
cuit (vehicle-  
specific  
with radial seal at  
inlet and outlet  
♦ Adapter - VAS  
6338/8- (2x re‐  
quired)  
Workshop  
Manual)  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
Audi A4 – Compressor Receiver (different ver‐ Expansion  
(8K_)  
manufacturer sions)  
valve re‐  
moved and  
2008 ►  
“Denso”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
– Adapter not re‐  
quired, receiver re‐ Adapter -  
mains in position  
VAS  
6338/36-  
– Depending on the (or drilled-  
version of the con‐ open ex‐  
denser, it may be pansion  
6338/12-  
♦ High-pres‐  
sure side:  
necessary to re‐  
valve e.g.  
move the desiccant 8K0 820  
cartridge from the 679 A) fit‐  
receiver on the con‐ ted  
adapter -  
VAS 6338/3-  
denser before  
⇒
flushing and to seal page 105  
the opening again – Refrig‐  
(see note).  
erant  
line  
with in‐  
ternal  
heat  
ex‐  
chang‐  
er is not  
re‐  
moved  
or is re-  
instal‐  
led af‐  
ter in‐  
stalla‐  
tion of  
adapt‐  
er.  
134  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A4 – Compressor – No adapter re‐  
Expansion  
(8W_)  
2016 ►  
Audi A4  
(86_)  
manufacturer  
“Denso” or  
“Sanden”  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
♦ Low-pres‐  
sure side:  
adapter -  
denser and the  
VAS  
2017 ►  
opening is sealed 6338/44-  
off again.  
installed  
(or an old  
expansion  
valve is  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
drilled  
open and  
installed as  
an adapter  
⇒
adapter -  
VAS 6338/3-  
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue .  
Note  
♦ The design of the receiver on the Audi A4 (8K_) 2008 > differs  
depending on the condenser manufacturer ⇒ Heating, air  
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual). Depending on the version of the condens‐  
er, the receiver may be attached to or integrated into the  
condenser. The integrated receiver contains a desiccant car‐  
tridge which is currently not always available as a replacement  
part. Therefore it may be necessary to renew the condenser  
after eliminating any faults on vehicles fitted with this con‐  
denser ⇒ Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
5. Refrigerant circuit  
135  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A5 Coupé and Sportback, Audi Q5, Audi A5 Cabriolet  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to air  
conditioner com‐  
pressor  
ments  
Audi A5 – Compressor Receiver (different ver‐ Expansion  
Coupé  
and  
manufacturer sions)  
valve re‐  
moved and  
“Denso”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
– Adapter not re‐  
Sport‐  
back  
quired, receiver re‐ adapter -  
mains in position  
VAS  
(8T_)  
6338/36-  
2008 ►  
Audi Q5  
(8R_ /  
83_)  
– Depending on the (or drilled-  
version of the con‐ open ex‐  
denser, it may be pansion  
6338/12-  
♦ High-pres‐  
sure side:  
necessary to re‐  
valve e.g.  
2008 ►  
Audi A5  
Cabrio‐  
let (8F_)  
2009 ►  
move the desiccant 8K0 820  
cartridge from the 679 A) fit‐  
receiver on the con‐ ted  
adapter -  
VAS 6338/3-  
denser before  
⇒
flushing and to seal page 105  
the opening again – Refrig‐  
(see note).  
erant  
line  
with in‐  
ternal  
heat  
ex‐  
chang‐  
er is not  
re‐  
moved  
or is re-  
instal‐  
led af‐  
ter in‐  
stalla‐  
tion of  
adapt‐  
er.  
Audi A5 – Compressor – No adapter re‐  
Expansion  
(F5_)  
manufacturer  
“Denso” or  
“Sanden”  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
2016 ►  
Audi Q5  
(FY_)  
♦ Low-pres‐  
sure side:  
adapter -  
denser and the  
VAS  
2017 ►  
Audi Q5  
(87_)  
opening is sealed 6338/44-  
off again.  
installed  
(or an old  
expansion  
valve is  
VAS  
2019  
6338/12-  
♦ High-pres‐  
sure side:  
drilled  
open and  
installed as  
an adapter  
⇒
adapter -  
VAS 6338/3-  
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue .  
136  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ The receiver version varies on these vehicles depending on  
the manufacturer of the condenser ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual). Depending on the version of the condenser, the  
receiver may be attached to or integrated into the condenser.  
The integrated receiver contains a desiccant cartridge which  
is currently not always available as a replacement part. There‐  
fore it may be necessary to renew the condenser after elimi‐  
nating any faults on vehicles fitted with this condenser ⇒  
Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
5. Refrigerant circuit  
137  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi Q5 hybrid  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Audi Q5 Adapters re‐  
Receiver (different ver‐ Expansion  
(8R_)  
quired for con‐ sions)  
valve re‐  
2011 ► nections to air  
conditioner com‐  
pressor  
– Adapter not re‐  
moved and  
quired, receiver re‐ adapter -  
mains in position  
VAS  
– Compressor  
6338/36-  
manufacturer – Depending on the (or drilled-  
“Denso”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
version of the con‐ open ex‐  
denser, it may be pansion  
necessary to re‐  
valve e.g.  
move the desiccant 8K0 820  
cartridge from the 679 A) fit‐  
receiver on the con‐ ted  
6338/12-  
denser before  
⇒
♦ High-pres‐  
sure side:  
flushing and to seal page 105  
the opening again – Refrig‐  
adapter -  
(see note).  
erant  
line  
VAS 6338/3-  
with in‐  
ternal  
heat  
ex‐  
chang‐  
er is not  
re‐  
moved  
or is re-  
instal‐  
led af‐  
ter in‐  
stalla‐  
tion of  
adapt‐  
er.  
138  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
♦ Addi‐  
tio‐  
For flushing circuit with There are  
evaporator in front air various  
conditioning unit and ways of  
nally  
for a  
vehi‐  
cle  
condenser  
flushing  
♦ Adapter - VAS  
the circuit:  
6338/5- for sealing ♦ Shut-off  
with  
bat‐  
connection on low-  
pressure side (to  
second evaporator  
in battery cooling  
module)  
valve -  
N516-  
removed  
and  
tery  
cool‐  
ing  
shut-off  
valve -  
VAS  
mod‐  
ule  
♦ Adapter - VAS  
6338/11- for seal‐  
ing connection on  
high-pressure side  
(to second evapo‐  
rator in battery cool‐  
ing module)  
6338/42-  
installed  
in its  
place  
(see  
notes  
below).  
Renew  
shut-off  
valve -  
N516-  
after  
♦ Shut-off valve -  
VAS 6338/42- or  
adapter - VAG  
1785/5- to replace  
removed refriger‐  
ant shut-off valve 1  
for hybrid battery -  
N516- (see notes)  
flushing.  
♦ Flushing  
the cir‐  
cuit in  
one or  
two  
steps  
(see  
notes)  
To flush the evaporator Expansion  
in the battery cooling valve in re‐  
module and the attach‐ frigerant  
ed lines  
lines to  
♦ Adapter - VAS  
6338/3- for con‐  
second  
evaporator  
necting air condi‐ removed  
tioner service sta‐ and adapt‐  
tion to connection er - VAS  
on low-pressure  
side (to second  
evaporator).  
6338/36-  
installed  
(or old ex‐  
pansion  
valve re‐  
moved,  
drilled  
♦ Adapter - VAS  
6338/4- for con‐  
necting air condi‐  
tioner service sta‐  
tion to connection  
on high-pressure  
side (to second  
evaporator).  
open for  
flushing  
and re-in‐  
stalled  
⇒
page 105 ).  
5. Refrigerant circuit  
139  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Adapters / lines  
required for con‐  
nections on elec‐  
trically driven air  
conditioner com‐  
pressor (for  
♦ On the  
electri‐  
cally  
driven  
air con‐  
ditioner  
com‐  
flushing air con‐  
ditioner com‐  
press‐  
or, the  
refrig‐  
erant oil  
is to be  
re‐  
pressor)  
⇒ page 121  
(Flushing the  
electrically driv‐  
en air condition‐  
er compressor)  
moved  
by  
flushing  
in the  
direc‐  
tion of  
flow (it  
is not  
possi‐  
ble to  
flush in  
the op‐  
posite  
direc‐  
tion due  
to the  
valves  
instal‐  
led)  
♦ For the  
flushing  
proce‐  
dure,  
position  
the air  
condi‐  
tioner  
com‐  
pressor  
so that  
the  
con‐  
nection  
for the  
refrig‐  
erant  
line on  
the  
high-  
pres‐  
sure  
side is  
as low  
down  
as pos‐  
sible  
140  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ On vehicles with two evaporators, the refrigerant circuit is  
flushed in two / three steps.  
♦ Currently the connections on the expansion valves at the  
evaporator in the air conditioning unit and at the evaporator in  
the battery cooling module are identical; the only differences  
are the control characteristics and the refrigerant shut-off  
valve 2 for hybrid battery - N517- .  
♦ If a refrigerant shut-off valve 1 for hybrid battery - N516- is  
installed in the circuit to the evaporator in the air conditioning  
unit, the refrigerant circuit cannot be flushed. -N516- forms a  
constriction and prevents the refrigerant from flowing through  
at an adequate rate. If a shut-off valve - VAS 6338/42- is avail‐  
able, install on the -N516- and open. If there is no shut-off valve  
- VAS 6338/42- , but two adapters - VAG 1785/5- are available,  
the circuit can be flushed with the evaporator in the air condi‐  
tioning unit in one work step (re-assemble circuit with one filler  
hose and two adapters - VAG 1785/5- ). If there is no shut-off  
valve - VAS 6338/42- and only one adapter - VAG 1785/5- ,  
the circuit must be flushed in two operations. From the low-  
pressure connection on the air conditioner compressor via the  
evaporator in the air conditioning unit through to the connec‐  
tion for the removed -N516- and from the connection for the  
removed -N516- via the condenser to the high-pressure con‐  
nection on the air conditioner compressor.  
♦ After flushing, the refrigerant shut-off valve 1 for hybrid battery  
- N516- must be renewed ⇒ Heating, air conditioning; Rep.  
gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐  
ual).  
♦ The receiver version varies on these vehicles depending on  
the manufacturer of the condenser ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual). Depending on the version of the condenser, the  
receiver may be attached to or integrated into the condenser.  
The integrated receiver contains a desiccant cartridge which  
is currently not always available as a replacement part. There‐  
fore it may be necessary to renew the condenser after elimi‐  
nating any faults on vehicles fitted with this condenser ⇒  
Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
5. Refrigerant circuit  
141  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi 100, Audi A6 (4A_, 4B_ and 4F_), Audi allroad and Audi V8  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ reservoir connections quire‐  
nections to air  
conditioner com‐  
pressor  
ments  
Audi  
– Compressor Reservoir with differ‐ - Restrictor  
100 /  
manufacturer ent connection ver‐  
removed,  
pipe con‐  
nections  
re-assem‐  
bled  
Audi A6  
(4A_) ►  
1998  
“Zexel /  
sions  
Valeo” (screw ♦ Version 1  
connections)  
– Screw connection  
at inlet Adapter -  
VAS 6338/9-  
Audi A6 ♦ Low-pres‐  
(4B_)  
sure side:  
adapter -  
1998 ►  
Audi all‐  
road  
VAG 1785/8-  
– Screw connection  
at outlet Adapter -  
VAG 1785/8-  
♦ High-pres‐  
sure side:  
(4B_) ►  
2005  
adapter -  
Audi V8  
(4C_) ►  
1994  
VAG 1785/7-  
♦ Version 2  
– Compressor  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
and axial  
– Screw connection  
at inlet Adapter -  
VAS 6338/9-  
– Block connection  
with axial seal at  
outlet Adapter -  
VAS 6338/10-  
seal)  
♦ Low-pres‐  
sure side:  
adapter -  
♦ Version 3  
VAS  
– Block connections  
with axial seal at in‐  
let and outlet  
6338/12-  
♦ High-pres‐  
sure side:  
Adapter - VAS  
6338/10- (2x re‐  
quired)  
adapter -  
VAS 6338/2-  
Audi A6 – Compressor – Reservoir with  
- Restrictor  
(4F_)  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
seal)  
block connections removed,  
with radial seal at pipe con‐  
2005 ►  
inlet and outlet  
♦ Adapter - VAS  
6338/8- (2x re‐  
quired)  
nections  
re-assem‐  
bled  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
Note  
The specifications for the Audi A6 (4F_) 2005 ► also apply to the  
Audi S6 and Audi RS 6.  
142  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A6 (4G_ or 4X_ for China), Audi A7 (4G_ or 4X_ for China)  
Vehicle Adapters re‐ Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to air  
conditioner com‐  
pressor  
ments  
Audi A6 – Compressor Receiver (different ver‐ Expansion  
(4G_ /  
4X_)  
manufacturer sions)  
“Denso”  
valve re‐  
moved and  
– Adapter not re‐  
2011 ► ♦ Low-pres‐  
quired, receiver re‐ adapter -  
Audi A7  
(4G_ /  
4X_)  
sure side:  
adapter -  
VAS  
mains in position  
VAS  
6338/18-  
– Depending on the fitted (or  
version of the con‐ old expan‐  
denser, it may be sion valve  
2011 ►  
6338/12-  
♦ High-pres‐  
sure side:  
necessary to re‐  
removed,  
move the desiccant drilled  
cartridge from the open for  
receiver on the con‐ flushing  
adapter -  
VAS 6338/3-  
denser before  
and re-in‐  
flushing and to seal stalled  
the opening again  
(see note).  
⇒
page 105 ).  
Note  
♦ On certain versions for China the type designation 4X_ is used  
instead of 4G_.  
♦ The receiver version varies on these vehicles depending on  
the manufacturer of the condenser ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual) and ⇒ Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
5. Refrigerant circuit  
143  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A6 hybrid, Audi A6 e-tron  
Vehicle Adapters re‐ Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Audi A6 Adapters re‐  
Receiver (different ver‐ Expansion  
(4G_)  
quired for con‐ sions)  
valve re‐  
2012 ► nections to air  
conditioner com‐  
pressor  
– Adapter not re‐  
moved and  
quired, receiver re‐ adapter -  
mains in position  
VAS  
– Compressor  
6338/18-  
(or old, dril‐  
manufacturer A6 hybrid  
“Denso” (A6 – Depending on the led-out and  
hybrid) or  
“Sanden” (A6  
e-tron)  
version of the con‐ cleaned  
denser, it may be expansion  
necessary to re‐  
valve  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
move the desiccant ⇒  
cartridge from the page 105 )  
receiver on the con‐ installed.  
denser before  
– Refrig‐  
erant  
6338/12-  
flushing and to seal  
the opening again  
(see note).  
line  
♦ High-pres‐  
sure side:  
with in‐  
ternal  
heat  
adapter -  
A6 e-tron  
VAS 6338/3-  
– Detach receiver  
from bracket, turn it  
through 180 de‐  
grees with refriger‐  
ant lines attached,  
and secure it so  
that connections  
are at the bottom  
(this ensures that  
the refrigerant is ex‐  
tracted in liquid  
ex‐  
chang‐  
er is not  
re‐  
moved  
or is re-  
instal‐  
led af‐  
ter in‐  
stalla‐  
tion of  
adapt‐  
er.  
form during the  
flushing process  
and that the receiv‐  
er does not ice up;  
refer to note).  
144  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
♦ Addi‐  
tional‐  
ly for  
vehi‐  
cles  
For flushing circuit with There are  
evaporator in front air various  
conditioning unit and ways of  
condenser  
flushing  
♦ Adapter - VAS  
the circuit:  
with  
6338/5- for sealing ♦ Shut-off  
battery  
cool‐  
ing  
connection on low-  
pressure side (to  
second evaporator  
in battery cooling  
module or on heat  
exchanger)  
valve -  
N516- / -  
V424-  
removed  
and  
mod‐  
ule or  
heat  
shut-off  
valve -  
VAS  
ex‐  
♦ Adapter - VAS  
6338/11- for seal‐  
ing connection on  
high-pressure side  
(to second evapo‐  
rator in battery cool‐  
ing module or on  
heat exchanger)  
chang‐  
er  
6338/42-  
installed  
in its  
place  
(see  
notes  
below)  
♦ Shut-off valve -  
VAS 6338/42- or  
adapter - VAG  
♦ Flushing  
the cir‐  
cuit in  
one or  
two  
1785/5- for installa‐  
tion in place of re‐  
moved shut-off  
steps  
valve -N516- or -  
V424- (see notes)  
(see  
notes)  
For flushing evapora‐ Expansion  
tor in battery cooling valve in re‐  
module (Audi A6 hy‐ frigerant  
brid) or on heat ex‐  
lines to  
changer for high-volt‐ second  
age battery (Audi A6 e- evapora‐  
tron) and attached  
lines  
tor / heat  
exchanger  
removed  
♦ Adapter - VAS  
6338/3- for con‐  
and adapt‐  
necting air condi‐ er -VAS  
tioner service sta‐ 6338/36-  
tion to connection or -VAS  
on low-pressure  
side (to second  
evaporator).  
6338/18-  
(different  
connec‐  
tions, de‐  
pending on  
version) in‐  
stalled (or  
old expan‐  
sion valve  
removed,  
drilled  
♦ Adapter - VAS  
6338/4- for con‐  
necting air condi‐  
tioner service sta‐  
tion to connection  
on high-pressure  
side (to second  
evaporator).  
open for  
flushing  
♦ Shut-off valve -  
VAS 6338/42- for  
installation in place  
of removed shut-off  
valve -N516- / -  
V424-  
and re-in‐  
stalled  
⇒
page 105 ).  
5. Refrigerant circuit  
145  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Adapters / lines  
required for con‐  
nections on elec‐  
trically driven air  
conditioner com‐  
pressor (for  
♦ On the  
electri‐  
cally  
driven  
air con‐  
ditioner  
com‐  
flushing air con‐  
ditioner com‐  
press‐  
or, the  
refrig‐  
erant oil  
is to be  
re‐  
pressor)  
⇒ page 121  
(Flushing the  
electrically driv‐  
en air condition‐  
er compressor)  
moved  
by  
flushing  
in the  
direc‐  
tion of  
flow (it  
is not  
possi‐  
ble to  
flush in  
the op‐  
posite  
direc‐  
tion due  
to the  
valves  
instal‐  
led)  
♦ For the  
flushing  
proce‐  
dure,  
position  
the air  
condi‐  
tioner  
com‐  
pressor  
so that  
the  
con‐  
nection  
for the  
refrig‐  
erant  
line on  
the  
high-  
pres‐  
sure  
side is  
as low  
down  
as pos‐  
sible  
146  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ On certain versions for China the type designation 4X_ is used  
instead of 4G_.  
♦ On vehicles with two evaporators (one in the air conditioning  
unit and one in the battery cooling module or on the heat ex‐  
changer for high-voltage battery, e.g. on the Audi A6 e-tron),  
the refrigerant circuit is flushed in two/three operations.  
♦ The expansion valve on the evaporator in the air conditioning  
unit and on the evaporator in the battery cooling module ( re‐  
frigerant shut-off valve 2 for hybrid battery - N517- on the A6  
hybrid and the expansion valve with refrigerant shut-off valve  
2 - N640- on the A6 e-tron) do not always have the same con‐  
nections (and if they have the same connections, they also  
differ in terms of their characteristic curve) ⇒ Heating, air con‐  
ditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific  
Workshop Manual).  
♦ If a shut-off valve ( refrigerant shut-off valve 1 for hybrid battery  
- N516- on the A6 hybrid / refrigerant shut-off valve - V424- on  
the A6 e-tron) is installed in the circuit to the evaporator in the  
air conditioning unit, the refrigerant circuit cannot be flushed;  
-N516- ( -V424- ) forms a constriction and prevents the refrig‐  
erant from flowing through at an adequate rate. If a shut-off  
valve - VAS 6338/42- is fitted, install it in place of -N516- ( -  
V424- ) and open it. If there is no shut-off valve - VAS 6338/42-  
but two adapters - VAG 1785/5- are available, the circuit can  
be flushed with the evaporator in the air conditioning unit in  
one work step (re-assemble circuit with one filler hose and two  
adapters - VAG 1785/5- ). If there is no shut-off valve - VAS  
6338/42- and only one adapter - VAG 1785/5- , the circuit must  
be flushed in two operations. From the low-pressure connec‐  
tion on the air conditioner compressor via the evaporator in the  
air conditioning unit through to the connection for the removed  
-N516- (the -V424- ) and from the connection for the removed  
-N516- (the -V424- ) via the condenser to the high-pressure  
connection on the air conditioner compressor.  
♦ After flushing, the refrigerant shut-off valve 1 for hybrid battery  
- N516- ( -V424- ) must be renewed ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual).  
♦ On the Audi A6 e-tron, the receiver must be renewed after  
flushing ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit; Removing and installing receiver .  
♦ The receiver version varies on these vehicles depending on  
the manufacturer of the condenser ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual). Depending on the version of the condenser, the  
receiver may be attached to or integrated into the condenser.  
The integrated receiver contains a desiccant cartridge which  
is currently not always available as a replacement part. There‐  
fore it may be necessary to renew the condenser after elimi‐  
nating any faults on vehicles fitted with this condenser ⇒  
Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
5. Refrigerant circuit  
147  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
♦ On the Audi A6 hybrid, it may be sensible to remove the two  
refrigerant lines in the engine compartment from the internal  
heat exchanger in order to flush the components in the battery  
cooling module and the associated refrigerant lines. As a re‐  
sult, the adapters and associated refrigerant hoses necessary  
for the flushing process can be more easily fitted and removed  
⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit  
(vehicle-specific Workshop Manual).  
♦ On the Audi A6 hybrid, it is possible that the knurled nut for the  
filler hose cannot be screwed onto the connection properly if  
adapter - VAS 6338/3- is installed on the refrigerant line lead‐  
ing to the evaporator in the battery cooling module (depending  
on the tolerance at the outlet of the refrigerant pipe leading  
from the connection); if this is the case, carefully bend the re‐  
frigerant pipe approx. 1 mm to one side.  
Audi A6 (4A_ or 48_ for China), Audi A7 (4K_)  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to air  
conditioner com‐  
pressor  
ments  
Audi A6 – Compressor – No adapter re‐  
Expansion  
(4A_ or  
for 48_  
manufacturer  
“Denso”  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
for Chi‐ ♦ Low-pres‐  
na)  
sure side:  
adapter -  
VAS  
denser and the  
VAS  
2019 ►  
Audi A7  
(4K)  
opening is sealed 6338/44-  
off again.  
installed  
(or an old  
expansion  
valve is  
6338/12-  
connected to  
air condition‐  
er service  
station and  
adapter -  
VAS  
2018 ►  
drilled  
open and  
installed as  
an adapter  
⇒
6338/48-  
page 105 )  
⇒ Elec‐  
♦ High-pres‐  
sure side:  
tronic parts  
catalogue .  
adapter -  
VAS 6338/3-  
Note  
On vehicles with condensers with an integrated receiver / desic‐  
cant cartridge which cannot be renewed separately or which are  
not available as separate replacement parts, the condenser must  
be renewed (together with integrated desiccant cartridge) after  
flushing ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit (vehicle-specific Workshop Manual) and ⇒ Electronic parts  
catalogue .  
148  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A8  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A8 – Compressor Reservoir with differ‐ - Restrictor  
(4D_)  
manufacturer ent connection ver‐  
removed,  
pipe con‐  
nections  
re-assem‐  
bled  
1994 ►  
“Zexel /  
sions  
Valeo” (screw ♦ Version 1  
connections)  
– Screw connection  
♦ Low-pres‐  
sure side:  
at inlet Adapter -  
VAS 6338/9-  
adapter -  
VAG 1785/8-  
– Screw connection  
at outlet Adapter -  
VAG 1785/8-  
♦ High-pres‐  
sure side:  
adapter -  
VAG 1785/7-  
♦ Version 2  
– Compressor  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
and axial  
– Screw connection  
at inlet Adapter -  
VAS 6338/9-  
– Block connection  
with axial seal at  
outlet Adapter -  
VAS 6338/10-  
seal)  
♦ Low-pres‐  
sure side:  
adapter -  
♦ Version 3  
VAS  
– Block connections  
with axial seal at in‐  
let and outlet  
6338/12-  
♦ High-pres‐  
sure side:  
Adapter - VAS  
6338/10- (2x re‐  
quired)  
adapter -  
VAS 6338/2-  
Audi A8 – Compressor Reservoir  
- Restrictor  
(4E_)  
manufacturer – Block connections removed,  
2003 ►  
“Denso” (bloc  
k connections  
with radial  
seal)  
with radial seal at pipe con‐  
inlet and outlet  
♦ Adapter - VAS  
6338/8- (2x re‐  
quired)  
nections  
re-assem‐  
bled  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
5. Refrigerant circuit  
149  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
Audi A8 – Compressor – No adapter re‐  
Expansion  
(4H_)  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
seal)  
quired, the desic‐ valve re‐  
2010 ►  
cant bag is re‐  
moved from the  
moved and  
adapter -  
receiver at the con‐ VAS  
denser and the  
6338/18-  
♦ Low-pres‐  
sure side:  
adapter -  
opening sealed off fitted (or  
again for flushing. old expan‐  
sion valve  
removed,  
drilled  
VAS  
6338/12-  
open for  
flushing  
and re-in‐  
stalled  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
⇒
page 105 ).  
♦ Addi‐  
tio‐  
For flushing circuit with  
evaporator in front air  
conditioning unit  
nally  
for  
♦ Adapter - VAS  
6338/5- for sealing  
connection (“low-  
pressure side”) to  
second evaporator  
vehi‐  
cles  
with  
two  
evap‐  
ora‐  
tors  
(4-  
♦ Adapter - VAS  
6338/11- for seal‐  
ing connection  
(“high-pressure  
side”) to second  
evaporator  
zone  
air  
con‐  
di‐  
•
An additional hole  
may have to be dril‐  
led in the adapters  
(see below) to be  
able to seal the re‐  
frigerant lines with  
adapters - VAS  
tio‐  
ner)  
6338/5- and -VAS  
6338/11- .  
150  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to reser‐ quire‐  
nections to air  
conditioner com‐  
pressor  
voir/receiver  
ments  
For flushing second  
Expansion  
evaporator and corre‐ valve in re‐  
sponding pipes  
♦ Adapter - VAS  
6338/3- for con‐  
frigerant  
lines to  
second  
necting air condi‐ evaporator  
tioner service sta‐ removed  
tion to connection and adapt‐  
on low-pressure  
side (to second  
evaporator).  
er - VAS  
6338/18-  
installed  
(or old ex‐  
pansion  
valve re‐  
moved,  
drilled  
♦ Adapter - VAS  
6338/4- for con‐  
necting air condi‐  
tioner service sta‐  
tion to connection  
on high-pressure  
side (to second  
evaporator).  
open for  
flushing  
and re-in‐  
stalled  
⇒
•
The adapter may  
have to be re‐  
page 105 ).  
worked (see below)  
to be able to con‐  
nect the refrigerant  
line to adapter -  
VAS 6338/3- .  
Note  
♦ On vehicles with two evaporators, the refrigerant circuit is  
flushed in two steps.  
♦ Currently, the front and rear expansion valves have identical  
connections (only the control characteristic curves differ).  
Making additional bore in adapters - VAS 6338/5- and -VAS  
6338/11- .  
– Drill hole -A- in addition to hole provided (dimensions in illus‐  
tration are given in mm).  
Rework the adapter - VAS 6338/3- .  
5. Refrigerant circuit  
151  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
– By grinding or filing off material in area -A-, rework the adapter  
- VAS 6338/3- such that it can be connected without bending  
the refrigerant line (the dimensions in the illustration are given  
in mm).  
152  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A8 hybrid  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Audi A8 Adapters re‐  
Receiver (different ver‐ Expansion  
(4H_)  
quired for con‐ sions)  
valve re‐  
2012 ► nections to air  
conditioner com‐  
pressor  
– Adapter not re‐  
moved and  
quired, receiver re‐ adapter -  
mains in position  
VAS  
– Compressor  
6338/18-  
manufacturer – Depending on the (or old, dril‐  
“Denso”  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
version of the con‐ led-out and  
denser, it may be cleaned  
necessary to re‐  
expansion  
move the desiccant valve  
cartridge from the  
receiver on the con‐ page 105 )  
denser before installed.  
⇒
6338/12-  
♦ High-pres‐  
sure side:  
flushing and to seal – Refrig‐  
the opening again  
(see note).  
erant  
line  
adapter -  
VAS 6338/3-  
with in‐  
ternal  
heat  
ex‐  
chang‐  
er is not  
re‐  
moved  
or is re-  
instal‐  
led af‐  
ter in‐  
stalla‐  
tion of  
adapt‐  
er.  
5. Refrigerant circuit  
153  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
♦ Addi‐  
tio‐  
For flushing circuit with There are  
evaporator in front air various  
conditioning unit and ways of  
nally  
for a  
vehi‐  
cle  
condenser  
flushing  
♦ Adapter - VAS  
the circuit:  
6338/5- for sealing ♦ Shut-off  
with  
bat‐  
connection on low-  
pressure side (to  
second evaporator  
in battery cooling  
module)  
valve -  
N516-  
removed  
and  
tery  
cool‐  
ing  
shut-off  
valve -  
VAS  
mod‐  
ule  
♦ Adapter - VAS  
6338/11- for seal‐  
ing connection on  
high-pressure side  
(to second evapo‐  
rator in battery cool‐  
ing module)  
6338/42-  
installed  
in its  
place  
(see  
notes  
below).  
Renew  
shut-off  
valve -  
N516-  
after  
♦ Shut-off valve -  
VAS 6338/42- or  
adapter - VAG  
1785/5- to replace  
removed refriger‐  
ant shut-off valve 1  
for hybrid battery -  
N516- (see notes)  
flushing.  
♦ Flushing  
the cir‐  
cuit in  
one or  
two  
steps  
(see  
notes)  
To flush the evaporator Expansion  
in the battery cooling valve in re‐  
module and the attach‐ frigerant  
ed lines  
lines to  
♦ Adapter - VAS  
6338/3- for con‐  
second  
evaporator  
necting air condi‐ removed  
tioner service sta‐ and adapt‐  
tion to connection er - VAS  
on low-pressure  
side (to second  
evaporator).  
6338/36-  
installed  
(or old ex‐  
pansion  
valve re‐  
moved,  
drilled  
♦ Adapter - VAS  
6338/4- for con‐  
necting air condi‐  
tioner service sta‐  
tion to connection  
on high-pressure  
side (to second  
evaporator).  
open for  
flushing  
and re-in‐  
stalled  
⇒
page 105 ).  
154  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ receiver connections quire‐  
nections to/on air  
conditioner com‐  
pressor  
ments  
Adapters / lines  
required for con‐  
nections on elec‐  
trically driven air  
conditioner com‐  
pressor (for  
♦ On the  
electri‐  
cally  
driven  
air con‐  
ditioner  
com‐  
flushing air con‐  
ditioner com‐  
press‐  
or, the  
refrig‐  
erant oil  
is to be  
re‐  
pressor)  
⇒ page 121  
(Flushing the  
electrically driv‐  
en air condition‐  
er compressor)  
moved  
by  
flushing  
in the  
direc‐  
tion of  
flow (it  
is not  
possi‐  
ble to  
flush in  
the op‐  
posite  
direc‐  
tion due  
to the  
valves  
instal‐  
led)  
♦ For the  
flushing  
proce‐  
dure,  
position  
the air  
condi‐  
tioner  
com‐  
pressor  
so that  
the  
con‐  
nection  
for the  
refrig‐  
erant  
line on  
the  
high-  
pres‐  
sure  
side is  
as low  
down  
as pos‐  
sible  
5. Refrigerant circuit  
155  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ On vehicles with two evaporators, the refrigerant circuit is  
flushed in two / three steps.  
♦ Currently the expansion valve at the evaporator in the air con‐  
ditioning unit and at the evaporator in the battery cooling  
module do not have the same connections.  
♦ If a refrigerant shut-off valve 1 for hybrid battery - N516- is  
installed in the circuit to the evaporator in the air conditioning  
unit, the refrigerant circuit cannot be flushed. -N516- forms a  
constriction and prevents the refrigerant from flowing through  
at an adequate rate. If there is a shut-off valve - VAS 6338/42- ,  
install it in place of -N516- and open it; if there is no shut-off  
valve - VAS 6338/42- but two adapters - VAG 1785/5- are  
available, the circuit can be flushed with the evaporator in the  
air conditioning unit in one work step (re-assemble circuit with  
one filler hose and two adapters - VAG 1785/5- ). If there is no  
shut-off valve - VAS 6338/42- and only one adapter - VAG  
1785/5- , the circuit must be flushed in two operations. From  
the low-pressure connection on the air conditioner compressor  
via the evaporator in the air conditioning unit through to the  
connection for the removed -N516- and from the connection  
for the removed -N516- via the condenser to the high-pressure  
connection on the air conditioner compressor.  
♦ After flushing, the refrigerant shut-off valve 1 for hybrid battery  
- N516- must be renewed ⇒ Heating, air conditioning; Rep.  
gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐  
ual).  
♦ The receiver version varies on these vehicles depending on  
the manufacturer of the condenser ⇒ Heating, air condition‐  
ing; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Work‐  
shop Manual). Depending on the version of the condenser, the  
receiver may be attached to or integrated into the condenser.  
The integrated receiver contains a desiccant cartridge which  
is currently not always available as a replacement part. There‐  
fore it may be necessary to renew the condenser after elimi‐  
nating any faults on vehicles fitted with this condenser ⇒  
Electronic parts catalogue .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
156  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi A8 (4N)  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
Audi A8 – Compressor – No adapter re‐  
Expansion  
(4N)  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
seal)  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
2018 ►  
♦ Vehi‐  
cle  
denser and the  
VAS  
with  
opening is sealed 6338/44-  
one ♦ Low-pres‐  
off again.  
installed  
(or an old  
expansion  
valve is  
evap‐  
ora‐  
tor  
sure side:  
adapter -  
VAS  
6338/12-  
connected to  
air condition‐  
er service  
station and  
adapter -  
VAS  
drilled  
open and  
installed as  
an adapter  
⇒
page 105 )  
⇒ Elec‐  
6338/48-  
tronic parts  
catalogue .  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
♦ Addi‐  
tio‐  
For flushing circuit with Expansion  
evaporator in front air valve to  
nally  
for  
conditioning unit  
♦ Adapter - VAS  
6338/44- and  
evaporator  
in front air  
condition‐  
ing unit re‐  
vehi‐  
cles  
with  
2
adapter - VAS  
6338/43- (for seal‐ moved and  
ing refrigerant cir‐ adapter -  
cuit off from second VAS  
evap‐  
ora‐  
tors  
(4-  
evaporator)  
6338/44-  
installed.  
Expansion  
valve in re‐  
frigerant  
zone  
air  
con‐  
di‐  
lines to  
evaporator  
in rear air  
condition‐  
ing unit re‐  
moved and  
adapter -  
VAS  
tio‐  
ner)  
6338/43-  
installed.  
5. Refrigerant circuit  
157  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
For flushing second  
Expansion  
evaporator and corre‐ valve to  
sponding pipes  
♦ Adapter - VAS  
6338/44- and  
evaporator  
in front air  
condition‐  
ing unit re‐  
adapter - VAS  
6338/43- (for seal‐ moved and  
ing refrigerant cir‐ adapter -  
cuit off from evapo‐ VAS  
rator in front air  
6338/43-  
installed.  
Expansion  
valve in re‐  
frigerant  
conditioning unit)  
lines to  
evaporator  
in rear air  
condition‐  
ing unit re‐  
moved and  
adapter -  
VAS  
6338/44-  
installed.  
Note  
♦ On vehicles with two evaporators, the refrigerant circuit is  
flushed in two steps.  
♦ On vehicles with two evaporators, the refrigerant circuit with  
the evaporator in the front air conditioning unit is flushed first.  
The refrigerant circuit to the second evaporator (in the rear air  
conditioning unit) must be separated so that the refrigerant  
flows in the specified direction when the circuit is flushed. This  
is done by removing the expansion valve in the refrigerant  
lines to the second evaporator and installing the adapter - VAS  
6338/43- (closed adapter). After the refrigerant circuit with the  
evaporator in the air conditioning unit has been flushed, the  
two adapters -VAS 6338/43- and -VAS 6338/44- are renewed  
and the refrigerant circuit with the evaporator in the rear air  
conditioning unit is flushed.  
158  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi Q7 (4L_)  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
Audi Q7 – Compressor – No adapter re‐  
Expansion  
(4L_)  
2006 ►  
♦ Vehi‐  
cle  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
seal)  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
denser and the  
VAS  
with  
opening is sealed 6338/17-  
one ♦ Low-pres‐  
off again.  
or adapter  
- VAS  
evap‐  
ora‐  
tor (2  
zone  
air  
sure side:  
adapter -  
VAS  
6338/33-  
fitted de‐  
pending on  
version of  
expansion  
valve (or  
drilled-  
6338/12-  
♦ High-pres‐  
sure side:  
con‐  
di‐  
adapter -  
tio‐  
VAS 6338/3-  
ner)  
open ex‐  
pansion  
valve e.g.  
7L0 820  
712 A, 7H0  
820 679 B  
or 7L0 820  
679 C fit‐  
ted  
⇒
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue .  
♦ Addi‐  
tio‐  
For flushing circuit with  
evaporator in front air  
conditioning unit  
nally  
for  
♦ Adapter - VAS  
6338/5- for sealing  
connection (“low-  
pressure side”) to  
second evaporator  
vehi‐  
cles  
with  
2
evap‐  
ora‐  
tors  
(4-  
♦ Adapter - VAS  
6338/11- for seal‐  
ing connection  
(“high-pressure  
side”) to second  
evaporator  
zone  
air  
con‐  
di‐  
tio‐  
ner)  
5. Refrigerant circuit  
159  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
For flushing second  
Expansion  
evaporator and corre‐ valve at  
sponding pipes  
♦ Adapter - VAS  
6338/3- for con‐  
second  
evaporator  
removed  
necting air condi‐ and Adapt‐  
tioner service sta‐ er - VAS  
tion to connection 6338/17-  
on low-pressure  
side (to second  
evaporator).  
fitted (or  
drilled-  
open ex‐  
pansion  
valve e.g.  
7L0 820  
712 A fitted  
⇒
♦ Adapter - VAS  
6338/4- for con‐  
necting air condi‐  
tioner service sta‐  
tion to connection  
on high-pressure  
side (to second  
evaporator).  
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue  
Note  
On vehicles with two evaporators, the refrigerant circuit is flushed  
in two steps.  
160  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi Q7 (4M_), Audi Q8 (4M_)  
Vehicle Adapters re‐ Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
Audi Q7 – Compressor – No adapter re‐  
Expansion  
(4M_)  
2016 ►  
Audi Q8  
(4M_)  
2018  
manufacturer  
“Denso” (bloc  
k connections  
with radial  
seal)  
quired; the dryer is valve re‐  
removed from the moved and  
receiver at the con‐ adapter -  
denser and the  
VAS  
opening is sealed 6338/44-  
♦ Vehi‐ ♦ Low-pres‐  
off again.  
installed  
(or an old  
expansion  
valve is  
cle  
sure side:  
adapter -  
VAS  
with  
one  
evap‐  
ora‐  
tor  
6338/12-  
drilled  
open and  
installed as  
an adapter  
⇒
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue .  
♦ Addi‐  
tio‐  
For flushing circuit with Expansion  
evaporator in front air valve to  
nally  
for  
conditioning unit  
♦ Adapter - VAS  
6338/44- and  
evaporator  
in front air  
condition‐  
ing unit re‐  
vehi‐  
cles  
with  
2
adapter - VAS  
6338/43- (for seal‐ moved and  
ing refrigerant cir‐ adapter -  
cuit off from second VAS  
evap‐  
ora‐  
tors  
(4-  
evaporator)  
6338/44-  
installed.  
Expansion  
valve in re‐  
frigerant  
zone  
air  
con‐  
di‐  
lines to  
evaporator  
in rear air  
condition‐  
ing unit re‐  
moved and  
adapter -  
VAS  
tio‐  
ner)  
6338/43-  
installed.  
5. Refrigerant circuit  
161  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
er / to second evapo‐ ments  
conditioner com‐ rator  
pressor  
For flushing second  
Expansion  
evaporator and corre‐ valve to  
sponding pipes  
♦ Adapter - VAS  
6338/44- and  
evaporator  
in front air  
condition‐  
ing unit re‐  
adapter - VAS  
6338/43- (for seal‐ moved and  
ing refrigerant cir‐ adapter -  
cuit off from evapo‐ VAS  
rator in front air  
6338/43-  
installed.  
Expansion  
valve in re‐  
frigerant  
conditioning unit)  
lines to  
evaporator  
in rear air  
condition‐  
ing unit re‐  
moved and  
adapter -  
VAS  
6338/44-  
installed.  
Note  
♦ On vehicles with two evaporators, the refrigerant circuit is  
flushed in two steps.  
♦ On vehicles with two evaporators, the refrigerant circuit with  
the evaporator in the front air conditioning unit is flushed first.  
The refrigerant circuit to the second evaporator (in the rear air  
conditioning unit) must be separated so that the refrigerant  
flows in the specified direction when the circuit is flushed. This  
is done by removing the expansion valve in the refrigerant  
lines to the second evaporator and installing the adapter - VAS  
6338/43- (closed adapter). After the refrigerant circuit with the  
evaporator in the air conditioning unit has been flushed, the  
two adapters -VAS 6338/43- and -VAS 6338/44- are renewed  
and the refrigerant circuit with the evaporator in the rear air  
conditioning unit is flushed.  
162  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi Q7 e-tron (4M_)  
Vehicle Adapters re‐  
Adapters required Other re‐  
quired for con‐ for connections to quirements  
nections to air  
conditioner com‐ turn and shut-off  
pressor valves  
receiver / for non-re‐  
Audi  
– Compressor Receiver  
Expansion  
Q7 e-  
tron  
manufacturer – No adapter re‐ valve re‐  
“Sanden” (blo  
ck connec‐  
tions with ra‐  
dial seal)  
quired; the dryer moved and  
is removed from adapter -  
(4M_)  
2016 ►  
♦ Vehi‐  
the receiver at  
the condenser  
VAS  
6338/44- in‐  
cle ♦ Low-pres‐  
and the opening stalled (or an  
with  
one  
sure side:  
adapter -  
is sealed off  
again.  
old expan‐  
sion valve is  
drilled open  
and installed  
as an adapt‐  
er  
evap‐ VAS  
ora‐  
tor  
6338/12-  
♦ High-pres‐  
sure side:  
⇒ page 105 )  
⇒ Electronic  
parts cata‐  
logue .  
adapter -  
VAS 6338/3-  
Non-return valves Open or  
– 4 non-return close the  
valves removed, shut-off  
and shut-off  
valves  
valves (in‐  
stalled in  
( -6338/47-1-  
and  
place of the  
non-return  
valves) ac‐  
cording to  
the area to  
-6338/47-2- )  
from shut-off  
valve set -  
6338/47- instal‐ be cleaned  
led  
⇒ Heating,  
air condition‐  
ing; Rep. gr.  
87 ; Refriger‐  
ant circuit .  
Shut-off valve  
Open or  
– Fitted shut-off  
close the  
valve -V424- re‐ shut-off  
moved and shut- valve (instal‐  
off valve - VAS led in place  
6338/42- fitted  
instead  
of the shut-  
off valve) ac‐  
cording to  
the area to  
be cleaned.  
Renew re‐  
frigerant  
shut-off  
valve - V424-  
after flush‐  
ing.  
5. Refrigerant circuit  
163  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ The refrigerant circuit is flushed in 4 operations (flushing cy‐  
cles) on the Audi Q7 e-tron ⇒ Heating, air conditioning; Rep.  
gr. 87 ; Refrigerant circuit; Cleaning air conditioner refrigerant  
circuit .  
♦ In order for the entire refrigerant circuit to be flushed in the  
Audi Q7 e-tron, it is not just the installed shut-off valves that  
have to be in the correct position (open or closed). In addition,  
the electrically operated valves (in the valve block) also have  
to be in the right position. The electrical valves are activated  
via different routines stored in the corresponding control unit  
(e.g. in the thermal management control unit - J1024- ) ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit;  
Cleaning air conditioner refrigerant circuit .  
♦ To perform the flushing procedure on the Audi Q7 e-tron, the  
circuit is separated into multiple sections, which are then flush‐  
ed in one flushing cycle each. The circuit is separated by  
activation of the electrically activated valves and via the man‐  
ual shut-off valves (must be activated manually) ⇒ Heating,  
air conditioning; Rep. gr. 87 ; Refrigerant circuit; Cleaning air  
conditioner refrigerant circuit , ⇒ Vehicle diagnostic tester  
(“Guided Fault Finding”).  
♦ The layout of the different flushing circuits for the Audi Q7 e-  
tron is described in the vehicle-specific Workshop Manual ⇒  
Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit;  
Cleaning air conditioner refrigerant circuit .  
♦ On vehicles with condensers with an integrated receiver / des‐  
iccant cartridge which cannot be renewed separately or which  
are not available as separate replacement parts, the condens‐  
er must be renewed (together with integrated desiccant car‐  
tridge) after flushing ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒  
Electronic parts catalogue .  
♦ After flushing, the refrigerant receiver at the heat exchanger  
for heat pump operation must be renewed ⇒ Heating, air con‐  
ditioning; Rep. gr. 87 ; Refrigerant circuit .  
♦ After flushing, the refrigerant shut-off valve - V424- must be  
renewed ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant  
circuit .  
164  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi R8 (42_)  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ reservoir connections quire‐  
nections to air  
conditioner com‐  
pressor  
ments  
Audi R8 – Compressor Reservoir  
- Restrictor  
(42_)  
manufacturer – Block connections removed,  
2008 ►  
“Denso” (bloc  
k connections  
with radial  
seal)  
with radial seal at pipe con‐  
inlet and outlet  
♦ Adapter - VAS  
6338/8- (2x re‐  
quired)  
nections  
re-assem‐  
bled  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
Note  
♦ On the Audi R8, the engine must be removed to renew the air  
conditioner compressor. However, to flush the refrigerant cir‐  
cuit the refrigerant lines can be detached with the air condi‐  
tioner compressor installed ⇒ Heating, air conditioning; Rep.  
gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐  
ual). However, it is not advisable to flush the refrigerant circuit  
with the air conditioner compressor installed because the  
quantity of refrigerant oil cannot be measured while the air  
conditioner compressor is installed.  
♦ The two condensers are flushed while installed and in the di‐  
rection opposite to that of the refrigerant flow.  
5. Refrigerant circuit  
165  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi R8 (4S_)  
Vehicle Adapters re‐  
Adapters required for Other re‐  
quired for con‐ connections to receiv‐ quire‐  
nections to air  
conditioner com‐  
pressor  
er (with dryer)  
ments  
Audi R8 – Compressor Receiver  
Expansion  
(4S_)  
manufacturer – Block connections valve re‐  
2015 ►  
“Denso” (bloc  
k connections  
with radial  
seal)  
with radial seal at moved and  
inlet and outlet  
♦ Adapter - VAS  
6338/45- (2x re‐  
quired)  
adapter -  
VAS  
6338/36-  
installed  
(or an old  
expansion  
valve is  
♦ Low-pres‐  
sure side:  
adapter -  
VAS  
6338/12-  
drilled  
open and  
installed as  
an adapter  
⇒
♦ High-pres‐  
sure side:  
adapter -  
VAS 6338/3-  
page 105 )  
⇒ Elec‐  
tronic parts  
catalogue .  
Receiver  
removed  
and both  
refrigerant  
line con‐  
nections  
connected  
to each  
other with  
two adapt‐  
ers - VAS  
6338/45-  
and a com‐  
mercially  
available  
filler hose  
(short ver‐  
sion with  
5/8" thread  
on both  
sides)  
166  
Rep. gr.87 - Air conditioning system  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Note  
♦ On the Audi R8, the engine may have to be removed before  
renewing the air conditioner compressor (depending on en‐  
gine version). However, to flush the refrigerant circuit the  
refrigerant lines can be detached with the air conditioner com‐  
pressor installed ⇒ Heating, air conditioning; Rep. gr. 87 ;  
Refrigerant circuit (vehicle-specific Workshop Manual). How‐  
ever, it is not advisable to flush the refrigerant circuit with the  
air conditioner compressor installed because the quantity of  
refrigerant oil cannot be measured while the air conditioner  
compressor is installed.  
♦ The two condensers are flushed while installed and in the di‐  
rection opposite to that of the refrigerant flow.  
♦ A short filler hose is also included in the adapter set for refrig‐  
erant circuits - VAS 6338/1- .  
♦ Although it may be possible to flush the receiver, its large in‐  
ternal volume means that it may hold too much liquid refriger‐  
ant. When this refrigerant is extracted the reservoir ices up  
severely, the refrigerant only evaporates very slowly and the  
extraction process takes too long.  
5. Refrigerant circuit  
167  
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...  
Air conditioner with refrigerant R134a - Edition 11.2018  
Audi e-tron (GE_) 2019 ►  
Vehicle Adapters re‐  
Adapters required Other re‐  
quired for con‐ for connections to quirements  
nections to air receiver / for non-re‐  
conditioner com‐ turn and shut-off  
pressor valves  
Audi e- – Compressor Receiver  
Expansion  
tron  
manufacturer – No adapter re‐ valve re‐  
(GE_)  
2019 ▶  
“Sanden” (blo  
ck connec‐  
tions with ra‐  
dial seal)  
quired; the dryer moved and  
is removed from adapter -  
the receiver at  
the condenser  
VAS  
6338/44- in‐  
♦ Low-pres‐  
sure side:  
adapter -  
and the opening stalled (or an  
is sealed off  
again.  
old expan‐  
sion valve is  
drilled open  
and installed  
as an adapt‐  
er  
VAS  
6338/12-  
♦ High-pres‐  
sure side:  
⇒ page 105 )  
⇒ Electronic  
parts cata‐  
logue .  
adapter -  
VAS 6338/3-  
Non-return valves Open or  
– 4 non-return close the  
valves removed, shut-off  
and shut-off  
valves  
valves (in‐  
stalled in  
( -6338/47-1-  
and  
place of the  
non-return  
valves) ac‐  
cording to  
the area to  
-6338/47-2- )  
from shut-off  
valve set -  
6338/47- instal‐ be cleaned  
led  
⇒ Heating,  
air condition‐  
ing; Rep. gr.  
87 ; Refriger‐  
ant circuit .  
Shut-off valve  
Open or  
– Fitted shut-off  
close the  
valve -V424- re‐ shut-off  
moved and shut- valve (instal‐  
off valve - VAS led in place  
6338/42- fitted  
instead  
of the shut-  
off valve) ac‐  
cording to  
the area to  
be cleaned.  
Renew re‐  
frigerant  
shut-off  
valve - V424-  
after flush‐  
ing.  
168  
Rep. gr.87 - Air conditioning system  

Related Topics

Refrigerant circuit

Important repair notes for air conditioning systems
Converting refrigerant circuits from refrigerant R12 to refrigerant R134a
Working with the air conditioner service station
Blowing out refrigerant circuit with compressed air and nitrogen
Tracing leaks in refrigerant circuit

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