Get Renewing components of refrigerant circuit Guide for 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

9

Renewing components of refrigerant

circuit

⇒ “9.1 Renewing components”, page 272

9.1

Renewing components

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 .

272

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

– 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.

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- ).

Vehicles with start/stop system

Risk of injury - engine may start unexpectedly

The engine can start unexpectedly if the vehicle's start/stop sys‐

tem is activated. A message in the instrument cluster indicates

whether the start/stop system is activated.

– To deactivate the start/stop system, switch off the ignition.

All vehicles

WARNING

Risk of injury (frostbite).

Refrigerant may escape if the refrigerant circuit has not been

discharged.

Extract refrigerant before opening refrigerant circuit. Renewed

evaporation may create pressure in refrigerant circuit if refrig‐

erant circuit is not opened within 10 minutes following extrac‐

tion. Extract refrigerant again.

•

All components of the refrigerant circuit submitted for quality

analysis must always be sealed (use original sealing caps of

replacement part).

To date, the replacement parts "air conditioner compressor,

reservoir, receiver, evaporator and condenser" have been fil‐

led with nitrogen gas. This filling is being gradually discontin‐

ued/the pressure of the nitrogen filling is now so low that it is

no longer possible to perceive gas escaping upon initial open‐

ing.

•

On vehicles fitted with an air conditioner compressor without

a magnetic clutch, the engine should only be started following

9. Renewing components of refrigerant circuit

273

Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...

Air conditioner with refrigerant R134a - Edition 11.2018

the complete assembly of the refrigerant circuit (with com‐

pressor always in operation).

•

When the refrigerant circuit is empty, the air conditioner com‐

pressor with air conditioner compressor regulating valve -

N280- (no magnetic clutch) is switched to internal lubrication

with the result that only a minimal amount of oil is pumped from

the air conditioner compressor into the circuit.

Note

♦ As parts are sometimes stored for lengthy periods and at dif‐

ferent locations within the spare parts organisation, it is en‐

tirely possible that gas will escape from some parts and not

from others on initial opening (even in the case of identical

spare part numbers). Sealing caps at replacement part con‐

nections must therefore be detached carefully and the nitro‐

gen gas allowed to escape slowly.

♦ Refrigerant circuits are fitted either with a restrictor and reser‐

voir or with an expansion valve and receiver.

♦ Always renew desiccant cartridge or components with desic‐

cant bag (reservoir, receiver) after cleaning refrigerant circuit

(flushing with refrigerant R134a ⇒ page 100 or blowing out with

compressed air and nitrogen ⇒ page 95 ); when doing so,

leave sealed as long as possible to minimise the absorption of

moisture.

♦ Renew desiccant cartridge or components with desiccant bag

(reservoir, receiver) if required for certain repair operations or

if the refrigerant circuit has been open for a relatively long pe‐

riod and moisture has entered (e.g. following an accident)

⇒ page 275 .

♦ The period of time for which a refrigerant circuit may be left

open without having to renew a component with desiccant bag

(reservoir, receiver) depends strongly on ambient influences.

At high ambient temperatures and high humidity levels, or if

the vehicle has been standing e.g. in the open or driven (in

wet, foggy weather conditions), this period of time will be con‐

siderably shorter than for a vehicle which has been standing

in a heated, dry area. The size of the opening through which

moisture may enter into the circuit also influences the period

for which a refrigerant circuit can be left open without having

to renew components with desiccant bag ⇒ page 275 .

♦ Seal open connections and lines (to prevent absorption of

moisture).

♦ Always renew restrictor.

Caution

♦ Contaminated refrigerant oils must be disposed of as used

oils of unknown origin (observe local regulations) ⇒ Audi

ServiceNet, HSO Environmental Protection .

274

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

⇒ “9.1.1 Leaking or damaged components (except air conditioner

compressor, reservoir or receiver)”, page 275

⇒ “9.1.2 Leaking or damaged components (except air conditioner

compressor, reservoir or receiver)”, page 277

⇒ “9.1.3 Renewing air conditioner compressor without having to

clean refrigerant circuit”, page 277

⇒ “9.1.4 Renewing air conditioner compressor due to leakage or

internal damage”, page 280

⇒ “9.1.5 Renewing receiver or reservoir and restrictor after clean‐

ing refrigerant circuit”, page 283

⇒ “9.1.6 Renewing receiver or reservoir without having to clean

refrigerant circuit”, page 284

⇒ “9.1.7 Renewing desiccant cartridge/desiccant bag without

having to clean refrigerant circuit”, page 285

⇒ “9.1.8 Removing/installing and renewing air conditioner com‐

pressor regulating valve N280 ”, page 285

9.1.1

Leaking or damaged components (ex‐

cept air conditioner compressor, reser‐

voir or receiver)

Refrigerant circuit completely empty (e.g. in the event of major

leakage or a burst hose)

Note

♦ In the event of only a minor leak with slow escape of refrigerant

(e.g. at a small leakage point), the amount of refrigerant oil lost

and the amount of moisture ingressing is not sufficient to in‐

fluence operation of the air conditioner.

♦ The work marked * must only be performed if there is a major

leak (e.g. following an accident).

Electrically driven air conditioner compressor

– Remove faulty component ⇒ Heating, air conditioning; Rep.

gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐

ual).

– Remove and flush the electrically driven air conditioner com‐

pressor ⇒ page 119 *.

– Clean the refrigerant circuit (flush with refrigerant R134a)

⇒ page 100 *.

– Pour the full specified quantity of refrigerant oil into the air

conditioner compressor or circuit *.

Mechanically driven air conditioner compressor

– Remove faulty component ⇒ Heating, air conditioning; Rep.

gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐

ual).

– Removing the air conditioner compressor ⇒ Heating, air con‐

ditioning; Rep. gr. 87 ; Air conditioner compressor (vehicle-

specific Workshop Manual)*.

9. Renewing components of refrigerant circuit

275

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Air conditioner with refrigerant R134a - Edition 11.2018

– Remove oil drain plug -B-/-D- from air conditioner compressor

-A-.*

Note

♦ The design of the oil drain plug -B- / -D- and the seal -C- /

-E- varies (depending on the air conditioner compressor man‐

ufacturer).

♦ Observe the correct tightening torque when fitting the oil drain

plug -B- / -D- (depends on the air conditioner compressor

manufacturer and the design of the oil drain plug). For exam‐

ple, on air conditioner compressors manufactured by Denso

or Delphi, a seal is fitted at the oil drain plug (tightening torque:

currently 30 Nm for Denso, and 15 Nm for Delphi). On air con‐

ditioner compressors manufactured by Sanden or Zexel/Va‐

leo, an O-ring or a seal is fitted at the oil drain plug depending

on the version (tightening torque: currently 10 Nm for O-ring

and seal).

♦ On Denso/Nippondenso or Delphi air conditioner compres‐

sors, for example, a seal -E- is fitted at the oil drain plug -D-;

renewing seal ⇒ Electronic parts catalogue .

♦ On air conditioner compressors manufactured by Sanden or

Zexel/Valeo, an O-ring or a seal -C- is fitted at the oil drain plug

-B-, depending on the version; renewing O-ring/seal ⇒ Elec‐

tronic parts catalogue .

♦ If the seal/O-ring fitted at the oil drain plug cannot be supplied

as a replacement part, the removed component can be re-in‐

stalled as an exception; it must be checked for damage before

being re-installed. If the removed seal/O-ring is damaged or

deformed, it must be replaced by a commercially available

component.

♦ To accelerate discharging of refrigerant oil, rotate air condi‐

tioner compressor e.g. via clutch plate of magnetic clutch.

♦ After charging the refrigerant circuit, check the installed oil

drain plug for leaks, e.g. with an electronic leak detector.

♦ Pour the old refrigerant oil out of the air conditioner compres‐

sor (disposal ⇒ Audi ServiceNet, HSO Environmental Protec‐

tion ).

All vehicles:

Note

♦ Then fill the air conditioner compressor with the quantity of

fresh refrigerant oil corresponding to the quantity of refrigerant

oil in the replacement compressor ⇒ page 333 *.

♦ Use different refrigerant oils and quantities for the various air

conditioner compressors ⇒ page 333 .

♦ To ensure air conditioner compressor lubrication on start-up,

3

at least 40 cm of refrigerant oil must be poured into the air

conditioner compressor. The remainder can be added for ex‐

ample to the new reservoir or receiver ⇒ page 333 .

♦ If dirt has entered into the air conditioner compressor with the

refrigerant circuit open (e.g. after an accident), renew the air

conditioner compressor.

♦ Clean refrigerant circuit (flush with refrigerant R134a

⇒ page 100 or blow out with compressed air or nitrogen

⇒ page 95 )*.

276

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

– Renew desiccant cartridge*, receiver* or reservoir* and re‐

strictor ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant

circuit (vehicle-specific Workshop Manual).

– Assemble, evacuate and re-charge refrigerant circuit.

9.1.2

Leaking or damaged components (ex‐

cept air conditioner compressor, reser‐

voir or receiver)

Refrigerant circuit still contains refrigerant (e.g. in the event of a

minor leak)

– Discharge refrigerant circuit.

– Remove defective component, flush with compressed air and

collect escaping refrigerant oil.

– Charge new component with amount of refrigerant oil blown

3

out (plus 20 cm for evaporator, plus 10 cm for condenser,

refrigerant lines and refrigerant hoses) as fresh refrigerant oil

fill.

Note

Disposal of old refrigerant oil ⇒ Audi ServiceNet, HSO Environ‐

mental Protection .

– Renew restrictor ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit (vehicle-specific Workshop Manual).

– Assemble, evacuate and charge refrigerant circuit.

9.1.3

Renewing air conditioner compressor

without having to clean refrigerant circuit

Note

♦ Cleaning the refrigerant circuit means flushing it with refriger‐

ant R134a ⇒ page 100 .

♦ 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 .

For example in the event of exterior damage after an accident (or

in the event of an electrical fault)

– Discharge refrigerant circuit.

– Remove air conditioner compressor ⇒ Heating, air condition‐

ing; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific

Workshop Manual).

Note

Use different refrigerant oils and quantities for the various air con‐

ditioner compressors

⇒ “10.2.2 Refrigerant oil capacities”, page 337 .

9. Renewing components of refrigerant circuit

277

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Air conditioner with refrigerant R134a - Edition 11.2018

Electrically driven air conditioner compressor

♦ If an electrically driven air conditioner compressor is renewed,

the quantity of refrigerant oil in the removed air conditioner

compressor must be determined by flushing

( ⇒ “5.5.2 Flushing electrically driven air conditioner compres‐

sor (removing refrigerant oil)”, page 119 ) the air conditioner

compressor. You must then pour enough refrigerant oil out of

the new air conditioner compressor so that the quantity of re‐

frigerant oil remaining in the compressor is the same as the

quantity flushed from the removed compressor

( ⇒ “10.2.2 Refrigerant oil capacities”, page 337 ).

Example:

3

♦

120 cm was flushed out of the air conditioner compressor to

be renewed

⇒ “5.5.2 Flushing electrically driven air conditioner compressor

(removing refrigerant oil)”, page 119 .

♦ The air conditioner compressor to be installed contains 200

3

cm of refrigerant oil (see rating plate and

⇒ “10.2.2 Refrigerant oil capacities”, page 337 ).

– Pour refrigerant oil out of the new air conditioner compressor

(first using the connection for the refrigerant line on the low-

pressure side) until the quantity of refrigerant oil remaining is

the same as the quantity previously flushed out of the air con‐

3

ditioner compressor to be renewed (plus 10 cm ). In the ex‐

3

ample, this is 110 cm of refrigerant oil (this ensures that the

refrigerant circuit contains the correct quantity of refrigerant oil

after the new air conditioner compressor is installed).

278

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

♦ 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, the air conditioner

compressor cannot be turned and the internal structure means

that, depending on the version of the air conditioner compres‐

sor and how it was stored, only a small amount of the refrig‐

erant oil can be poured out (due to differences in how the

refrigerant oil is distributed in the air conditioner compressor).

3

A residual quantity of between 30 and 80 cm will usually re‐

main in the air conditioner compressor after the pouring oper‐

ation. Depending on the problem, the removed air conditioner

compressor must therefore be flushed in order to remove the

refrigerant oil and determine the quantity contained

⇒ “5.5.2 Flushing electrically driven air conditioner compressor

(removing refrigerant oil)”, page 119 .

♦ If the required quantity of refrigerant oil cannot be poured out

of the air conditioner compressor to be newly installed, then

the new air conditioner compressor must also be flushed. The

new air conditioner compressor must then be filled up with the

same quantity of new refrigerant oil as was previously flushed

out of the old air conditioner compressor

⇒ “5.5.2 Flushing electrically driven air conditioner compressor

(removing refrigerant oil)”, page 119 .

♦ The refrigerant oil has roughly the same density as water at

room temperature (1 kg corresponds to one litre).

♦ Even electric air conditioner compressors of the same con‐

struction (same manufacturer, same part number) do not

weigh the same, which means that the quantity of refrigerant

oil they contain cannot be determined by weighing them (the

tolerances are too large to determine the quantity of refrigerant

oil by weighing).

♦ The distribution of the refrigerant oil in the air conditioner com‐

pressor differs depending on the structure and how the air

conditioner compressor is stored. There can be some in the

compression chamber and some in the area of the electric

motor, in which case the refrigerant oil must be alternately

poured out via the two connections for the refrigerant pipes

(high and low-pressure side). The air conditioner compressor

must be positioned so that the respective connection is as low

as possible.

♦ Dispose of refrigerant oil which is no longer required after

flushing out of the defective air conditioner compressor and

pouring out of the new air conditioner compressor ⇒ Audi

ServiceNet, HSO Environmental Protection (observe local

regulations).

Mechanically driven air conditioner compressor

– Remove the oil drain plug from the air conditioner compressor

(mechanically driven air conditioner compressor).

Note

There are different versions of the oil drain plug and the corre‐

sponding seal (an O-ring or a seal may be fitted, always renew)

⇒ page 275 and ⇒ Electronic parts catalogue .

– To accelerate discharging of refrigerant oil, rotate air condi‐

tioner compressor e.g. via clutch plate of magnetic clutch.

9. Renewing components of refrigerant circuit

279

Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...

Air conditioner with refrigerant R134a - Edition 11.2018

– Pour the old refrigerant oil out of the air conditioner compres‐

sor and dispose of it ⇒ Audi ServiceNet, HSO Environmental

Protection (observe local regulations).

– Remove the oil drain plug from the replacement compressor,

pour out the refrigerant oil into a clean vessel and only add a

quantity of fresh refrigerant oil equal to the amount poured out

of the defective air conditioner compressor.

Caution

Risk of damage to the air conditioner compressor due to con‐

taminated refrigerant oil

♦ Refrigerant oil that has been poured out of a new air con‐

ditioner compressor may only be re-used if it is in a clean

vessel and the required quantity is added back into the air

conditioner compressor immediately after pouring.

♦ Do not re-use refrigerant oil into which dirt or moisture has

gotten; it must be disposed of.

Note

3

♦

If, for example, 70 cm of refrigerant oil has been poured out

3

of the defective air conditioner compressor and 220 cm out

of the replacement compressor (a small quantity of refrigerant

oil remains in the air conditioner compressor), In this case, fill

3

up the air conditioner compressor to be installed with 70 cm

of refrigerant oil. The refrigerant oil poured out of the new (re‐

placement) air conditioner compressor may be used if there is

no dirt or moisture in it).

♦ Use different refrigerant oils and quantities for the various air

conditioner compressors ⇒ page 292 .

♦ If a greater quantity of refrigerant oil (more than approx. 40

3

cm ) has been poured out of the defective air conditioner com‐

pressor, the remaining refrigerant oil can also be added to the

evaporator or reservoir/receiver ⇒ page 292 .

All vehicles:

– Renew restrictor (only if installed in this refrigerant circuit).

– Assemble, evacuate and charge refrigerant circuit.

9.1.4

Renewing air conditioner compressor

due to leakage or internal damage

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.

280

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.

9. Renewing components of refrigerant circuit

281

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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

For example due to noise from the air conditioner compressor or

no air conditioner compressor output

Note

♦ The refrigerant circuit does not always need to be cleaned in

the event of damage to the electrical components of the air

conditioner compressor, for example the air conditioner com‐

pressor regulating valve - N280- of the mechanically driven air

conditioner compressor or the air conditioner compressor con‐

trol unit - J842- of the electrically driven air conditioner com‐

pressor. In this case it is usually sufficient to renew the air

conditioner compressor without cleaning the refrigerant circuit

(adjust the quantity of refrigerant oil)

⇒ “9.1.3 Renewing air conditioner compressor without having

to clean refrigerant circuit”, 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 .

– Discharge refrigerant circuit.

– Remove air conditioner compressor ⇒ Heating, air condition‐

ing; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific

Workshop Manual).

– Clean refrigerant circuit (flush with refrigerant R134a)

⇒ page 100 .

Note

♦ In the event of internal (air conditioner compressor) damage,

check refrigerant hoses and condenser. If e.g. swarf has en‐

tered, clean refrigerant hoses and condenser (flush with re‐

frigerant R134a ⇒ page 100 ) and renew refrigerant hoses if

necessary.

♦ On vehicles with two evaporators, the quantity of refrigerant

oil in the refrigerant circuit may be greater than the quantity in

the replacement compressor. On such vehicles, add the extra

quantity of refrigerant oil to the refrigerant circuit as necessary

⇒ page 95 .

282

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

– Renew desiccant cartridge, receiver or reservoir and restrictor

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific Workshop Manual).

– Check expansion valve for dirt and corrosion, and renew if

necessary ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific Workshop Manual).

– Assemble, evacuate and charge refrigerant circuit.

9.1.5

Renewing receiver or reservoir and re‐

strictor after cleaning refrigerant circuit

Note

Cleaning refrigerant circuit means flushing with refrigerant R134a

⇒ page 100 or blowing out with compressed air or nitrogen

⇒ page 95 .

Due to moisture entering (refrigerant circuit open for lengthy pe‐

riod) or contamination (example)

– Discharge refrigerant circuit.

– Remove air conditioner compressor ⇒ Heating, air condition‐

ing; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific

Workshop Manual).

– Eliminate cause of fault.

– Clean refrigerant circuit (flush with refrigerant R134a)

⇒ page 100 .

– Check expansion valve for dirt or corrosion and renew if nec‐

essary

Electrically driven air conditioner compressor

– Flush old refrigerant oil out of air conditioner compressor

⇒ “5.5.2 Flushing electrically driven air conditioner compressor

(removing refrigerant oil)”, page 119 .

Mechanically driven air conditioner compressor

– Remove oil drain plug from air conditioner compressor.

Note

There are different versions of the oil drain plug and the corre‐

sponding seal (an O-ring or a seal may be fitted; renew)

⇒ page 275 and ⇒ Electronic parts catalogue .

– To accelerate discharging of refrigerant oil, rotate air condi‐

tioner compressor e.g. via clutch plate of magnetic clutch.

– Pour old refrigerant oil out of air conditioner compressor.

Note

Dispose of old refrigerant oil ⇒ Audi ServiceNet, HSO Environ‐

mental Protection (observe local regulations).

All air conditioner compressors

– Then add the quantity of fresh refrigerant oil to the air condi‐

tioner compressor corresponding to the quantity of refrigerant

oil in the replacement compressor (or the specified quantity of

9. Renewing components of refrigerant circuit

283

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Air conditioner with refrigerant R134a - Edition 11.2018

refrigerant oil on vehicles with two evaporators if applicable)

⇒ page 333 .

Note

♦ Use different refrigerant oils and quantities for the various air

conditioner compressors ⇒ page 333 .

♦ To ensure air conditioner compressor lubrication on start-up,

3

at least 40 cm of refrigerant oil must be poured into the air

conditioner compressor. The remainder can be added for ex‐

ample to the new reservoir or receiver ⇒ page 292 .

♦ If dirt has entered into the air conditioner compressor with the

refrigerant circuit open (e.g. after an accident), renew the air

conditioner compressor.

♦ On vehicles with two evaporators, the quantity of refrigerant

oil in the refrigerant circuit may be greater than the quantity in

the replacement compressor. On such vehicles, add the extra

quantity of refrigerant oil to the refrigerant circuit as necessary

⇒ page 95 .

All vehicles

– Renew receiver or reservoir and restrictor ⇒ Heating, air con‐

ditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific

Workshop Manual).

– Assemble, evacuate and charge refrigerant circuit.

9.1.6

Renewing receiver or reservoir without

having to clean refrigerant circuit

Note

Cleaning refrigerant circuit means flushing with refrigerant R134a

⇒ page 100 or blowing out with compressed air or nitrogen

⇒ page 95 .

For example in the event of accident damage; no refrigerant es‐

caped and no ingress of moisture and dirt into the circuit.

– Discharge refrigerant circuit.

– Renew restrictor ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit (vehicle-specific Workshop Manual).

– Remove receiver or reservoir ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop

Manual).

– Remove dirt from receiver or reservoir.

– Weigh receiver or reservoir removed.

– Fill the new receiver or reservoir with refrigerant oil until it at‐

tains the weight of the vessel removed.

– Install new receiver or reservoir.

– Assemble, evacuate and charge refrigerant circuit.

284

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

9.1.7

Renewing desiccant cartridge/desiccant

bag without having to clean refrigerant

circuit

Note

Cleaning refrigerant circuit means flushing with refrigerant R134a

⇒ page 100 or blowing out with compressed air or nitrogen

⇒ page 95 .

In the event of a leak, refrigerant has escaped but no dirt has

entered the circuit (example)

– Discharge refrigerant circuit.

– Renew desiccant cartridge ⇒ Heating, air conditioning; Rep.

gr. 87 ; Refrigerant circuit (vehicle-specific Workshop Man‐

ual).

– Assemble, evacuate and charge refrigerant circuit.

9.1.8

Removing/installing and renewing air

conditioner compressor regulating valve

- N280-

9. Renewing components of refrigerant circuit

285

Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...

Air conditioner with refrigerant R134a - Edition 11.2018

Note

♦ Certain malfunctions of -N280- (e.g. sticking valve or open cir‐

cuit in coil) can lead to problems with air conditioner compres‐

sor (no cooling output from air conditioner, evaporator icing up

etc.). If -N280- is the cause (and not the actual air conditioner

compressor), the air conditioner compressor can be repaired

by renewing -N280- -C, D-.

♦ -N280- -C, D- is not available as a replacement part for all air

conditioner compressors. If -N280- cannot be obtained sepa‐

rately for a particular air conditioner compressor, the entire air

conditioner compressor must be renewed ⇒ Electronic parts

catalogue .

♦ -N280- is available in different versions and with different set‐

tings ⇒ Electronic parts catalogue . On the air conditioner

compressor -A- (in this case a “Denso” air conditioner com‐

pressor without air conditioning system magnetic clutch -

N25- ), the connector for connection to the vehicle wiring

harness is attached to -N280- -C- via a short wiring harness.

On the air conditioner compressor -B- (in this case a “Sanden”

air conditioner compressor), the connector for connection to

the vehicle wiring harness is attached directly to -N280- -C-.

The procedures for removing and installing versions

-C and D - of -N280- for other air conditioner compressors

(different version, different manufacturer) are essentially the

same and usually only differ slightly from the procedure de‐

scribed below.

♦ -N280- is available in different versions and with different set‐

tings ⇒ Electronic parts catalogue . On air conditioner com‐

pressors with -N25- (in this case a “Denso” air conditioner

compressor), the connector for connection to the vehicle wir‐

ing harness is attached directly to -N280- -A-. On the other air

conditioner compressor, the connector for connection to the

vehicle wiring harness is incorporated into a 3-pin connector

-E- for -N25- and -N280- .

♦ On version -B- of -N280- , the wiring may be connected directly

to -N280- or there may be an additional connector at -N280- .

♦ The procedure for removing and installing versions

-A and B- of -N280- is essentially the same and usually only

differs slightly from the procedure described below. On air

conditioner compressors with a 3-pin connector -E-, discon‐

nect the wires to -N280- from -N280- , unplug them from the

connector -E- or sever them at a suitable location (and re-

connect them using wiring connectors from wiring harness

repair set - VAS 1978 B- .

♦ If, after removing -N280- , the cause of the problem at -N280-

is found to be dirt, swarf or some other form of air conditioner

compressor abrasion, clean the refrigerant circuit and renew

the air conditioner compressor

⇒ “9.1.4 Renewing air conditioner compressor due to leakage

or internal damage”, page 280 and

⇒ “5.5 Cleaning (flushing) refrigerant circuit with refrigerant

R134a”, page 100

Removing

– Discharging refrigerant circuit

⇒ “5.3 Working with the air conditioner service station”,

page 79

286

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

Risk of air conditioner compressor damage if the refrigerant

circuit is empty

Never start the engine when the refrigerant circuit is empty.

♦ Depending on the version of the air conditioner service

station, the pressure in the refrigerant circuit may be less

than 1 bar absolute following drainage.

♦ Depending on the version, the air conditioner compressor

may be damaged by running it when the pressure in the

refrigerant circuit is low.

♦ Never start the engine if the pressure in the refrigerant

circuit is below ambient pressure.

– Depending on vehicle and fitting location of air conditioner

compressor, remove components impeding access to -N280-

⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant circuit

(vehicle-specific Workshop Manual).

Vehicles where it is not possible to detach or remove at least one

of the two refrigerant lines and -N280- with the air conditioner

compressor attached to the engine

– Remove air conditioner compressor ⇒ Heating, air condition‐

ing; Rep. gr. 87 ; Air conditioner compressor (vehicle-specific

Workshop Manual).

Note

With the air conditioner compressor in position, a refrigerant line

has to be detached to ensure that the pressure in the air condi‐

tioner compressor is the same as the ambient pressure.

Vehicles where it is possible to detach or remove at least one of

the two refrigerant lines and -N280- with the air conditioner com‐

pressor attached to the engine (air conditioner compressor is not

removed)

WARNING

Risk of injury (frostbite).

♦ Before removing -N280- , connect the air conditioner serv‐

ice station and extract refrigerant. The refrigerant circuit

must be empty; danger of injury.

♦ Refrigerant and refrigerant oil will emerge if the refrigerant

circuit has not been drained.

♦ The refrigerant is to be extracted before removing -N280- .

Renewed evaporation may create pressure in the refrig‐

erant circuit if -N280- is not removed within 10 minutes

following extraction. Extract refrigerant again.

– Check the pressure in the refrigerant circuit again by way of

the pressure gauge of the air conditioner service station.

♦ If the pressure displayed is higher than the ambient pressure

(greater than approx. 1 bar absolute), switch the air condition‐

er service station on again and extract the refrigerant causing

the pressure build-up.

9. Renewing components of refrigerant circuit

287

Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...

Air conditioner with refrigerant R134a - Edition 11.2018

– Detach one of the two refrigerant lines from air conditioner

compressor ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit (vehicle-specific Workshop Manual).

Note

With the air conditioner compressor in position, a refrigerant line

has to be detached to ensure that the pressure in the air condi‐

tioner compressor is the same as the ambient pressure.

All vehicles

– Before removing -N280- , check again whether the air condi‐

tioner compressor is actually being driven by the pulley/drive

unit. If the overload protection device of the pulley or drive unit

has been tripped, the malfunction is usually not caused by the

regulating valve, but by the air conditioner compressor (e.g.

because it is stiff).

Note

♦ This illustration shows -N280- -B- for a “Sanden” air condi‐

tioner compressor of type “PXE 14”. On these air conditioner

compressors, the connector for connection to the vehicle wir‐

ing harness is attached directly to -N280- -B-. Removal and

installation of -N280- -B- for other air conditioner compressors

(different type, different make e.g. “Denso”, -N280- with a short

wiring harness to the connector for example) may differ. The

basic procedure is however the same, as described below for

the “Sanden” air conditioner compressor of type “PXE 14”.

♦ This illustration shows an -N280- -B- with an O-ring -E- (not

fitted on all versions).

♦ In the case of an -N280- -B- with no O-ring -E-, dirt may ingress

into the mounting for -N280- -C- as far as the O-ring -F-.

– If fitted, unfasten wiring connecting -N280- -B- to vehicle wiring

harness connector from air conditioner compressor.

Note

♦ On air conditioner compressors with air conditioning system

magnetic clutch - N25- on which -N25- is activated via the

same connector as -N280- -B-, eject the corresponding wires

from the connector (e.g. with an ejector from the wiring har‐

ness repair set - VAS 1978 B- ) ⇒ Heating, air conditioning;

Rep. gr. 87 ; Refrigerant circuit (vehicle-specific Workshop

Manual).

♦ If an air conditioner compressor with air conditioning system

magnetic clutch - N25- has a connector from which the elec‐

trical wires cannot be ejected, sever the wires to -N280- (or to

-N25- ) at a suitable location and re-connect using wiring con‐

nectors from the wiring harness repair set - VAS 1978 B- (or

renew the connector; refer to ⇒ Electronic parts catalogue )

⇒ Electrical system; Rep. gr. 97 ; Connectors; Repairing

electrical wiring harnesses and electrical connectors .

288

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

– Thoroughly clean the air conditioner compressor in the area

of the circlip -A- and -N280- -B-.

Caution

The pressure in the air conditioner compressor must be the

same as the ambient pressure.

♦ Refrigerant and refrigerant oil may emerge in the event of

higher pressure in the air conditioner compressor.

♦ Dirt may be drawn into the air conditioner compressor in

the event of lower pressure in the air conditioner com‐

pressor.

♦ Ensure pressure equalisation before removing -N280-

-B-.

– Remove circlip -A-.

– Carefully remove -N280- -B- from the mounting on the air con‐

ditioner compressor -C- using a suitable screwdriver -D- for

example.

9. Renewing components of refrigerant circuit

289

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Air conditioner with refrigerant R134a - Edition 11.2018

– After removal, check -N280- -B- and mounting on air condi‐

tioner compressor -C- for dirt.

Note

♦ If the strainer -D-, -N280- -B- as far as the O-ring -F- or the

mounting on the air conditioner compressor -C- is severely

contaminated in this area (e g. with swarf or dark, tacky abra‐

sion), this is an indication of air conditioner compressor dam‐

age. In this case, clean the refrigerant circuit and renew air

conditioner compressor

⇒ “9.1.4 Renewing air conditioner compressor due to leakage

or internal damage”, page 280 and

⇒ “5.5 Cleaning (flushing) refrigerant circuit with refrigerant

R134a”, page 100

♦ If the strainer -D- at -N280- -B- and the mounting on the air

conditioner compressor -C- as far as the sealing surface of the

O-ring -F- are only slightly contaminated (e g. with light grey

deposits from normal air conditioner compressor operation),

the cause of air conditioner compressor malfunctioning may

be a problem with -N280- -B-.

♦ If -N280- -B- does not have an O-ring -E-, dirt may have en‐

tered the mounting -C- as far as the O-ring -E- during opera‐

tion. Carefully remove all dirt using a lint-free cloth or similar

(do not use compressed air).

Installing

– Check the mounting on the air conditioner compressor -C- and

the groove for the circlip for contamination and clean carefully

and thoroughly with a fresh lint-free cloth if necessary.

Caution

Dirt in the air conditioner compressor or damage to the sealing

surfaces in the mounting could lead to renewed failure of -

N280- -B- or the air conditioner compressor

♦ If necessary, carefully clean the mounting on the air con‐

ditioner compressor -C- with a fresh lint-free cloth (do not

use compressed air).

♦ When cleaning the mounting -C-, make sure no dirt in‐

gresses into the area beneath the sealing surface for the

O-ring -F- or into the ducts provided and that none of the

sealing surfaces of the mounting are damaged.

– Check air conditioner compressor mounting -C- for damage

(also check for small scratches on surface; renew air condi‐

tioner compressor if damage is found).

– Check the O-rings -F,G,H- and -E- (if fitted) of -N280- -B- for

damage.

– Moisten the O-rings -F,G,H- and -E- (if fitted) of -N280- -B- with

a small quantity of refrigerant oil and check for proper attach‐

ment.

– Insert -N280- -B- as far as it will go in air conditioner compres‐

sor mounting -C-.

– Fit a new circlip -A- and check for correct positioning in the

groove.

– Re-install all parts removed in reverse order.

290

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

– Evacuate and re-charge the refrigerant circuit

⇒ “5.3 Working with the air conditioner service station”,

page 79 .

Note

If refrigerant oil has emerged with -N280- -B- removed, use the

air conditioner service station to add this quantity of refrigerant oil

when charging the refrigerant circuit

⇒ “5.3 Working with the air conditioner service station”,

page 79 .

– Check operation of air conditioner

⇒ “8 Checking pressures”, page 193 and ⇒ Heating, air con‐

ditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific

Workshop Manual).

9. Renewing components of refrigerant circuit

291

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