Get Detectingleaksinrefrigerantcircuit Guide for Volkswagen LT Van Second Generation (1996-2006)

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

6

Detecting leaks in refrigerant circuit

Note

♦ Different processes are described in this workshop manual for

leak detection in the refrigerant circuit. These processes have

been tested and lead to a positive result under the different

conditions of use if the application is carried out correctly and

in accordance with the complaint.

lk

♦ When leak detection using compressed air/nitrogen or vac‐

uum does not produce results, use electronic leak detector or

UV leak detector additive.

♦ Small leaks can be detected with, for example, an electronic

leak detector or a UV leak detector lamp.

♦ A wide range of processes are offered on the open market for

finding leaks in refrigerant circuits. These processes do not

always produce conclusive results. If they are not used pre‐

cisely according to the specifications, they may even cause

components of the refrigerant circuit to develop leaks where

there were none before. Furthermore, certain processes can

cause preliminary or permanent damage to the components

of the refrigerant circuit

♦ Components that are found to be leaking must not be repaired.

They have to be replaced with genuine parts.

♦ A leaking refrigerant circuit must not be charged with refriger‐

ant, therefore evacuate an empty refrigerant circuit and check

for leaks before charging the system with refrigerant

⇒ page 50 .

Caution

♦ If there is evidence to suggest that chemical substances

have been added in the vehicle to seal leaks, do not con‐

nect the air conditioner service station and do not extract

the refrigerant.

♦ Chemical substances used to seal leaks form deposits in

the refrigerant circuit. These can impair the function of the

air conditioning system and cause the air conditioning

system (and your air conditioner service station) to fail.

♦ Make your customer aware of the fact that there are sub‐

stances in his/her air conditioning system that do not have

VW approval. This air conditioning system cannot be

drained or repaired by you.

6. Detecting leaks in refrigerant circuit

55

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦ Volkswagen rejects the use of chemical substances for pur‐

poses of sealing leaks in refrigerant circuits.

♦ Chemical substances used for sealing leaks in refrigerant cir‐

cuits often react with the surrounding air and the humidity

contained within. They cause deposits to build up in the re‐

frigerant circuit (and your air conditioner service station),

valves to malfunction and defects in other components with

which they come into contact. These deposits cannot be com‐

pletely removed from the components (not even by purging).

♦ It is often not possible to detect from the outside whether

chemical substances have been used to seal leaks in the re‐

frigerant circuit. The adhesive label that serves to identify its

use can usually not be found. Therefore, exercise caution

when working on vehicles for which you have no service or

repair record.

♦ Containers or tanks are offered as accessories on the open

market that are designed to separate these chemical substan‐

ces (to seal leaks). Since Volkswagen rejects the use of these

substances, no statement can be made at this point regarding

the effectiveness and separation rate of these filt_le_krs.

6.1

Leak detection in refrigerant circuit us‐

ing compressed air or nitrogen

56

Rep. gr.00 - Technical data

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦ A leak in the refrigerant circuit can be detected, for example,

by pressurising the circuit to a maximum of 15 bar using

cleaned and dried compressed air or nitrogen ⇒ page 65 . If

the leak is large, the leakage point can be detected by sound

as the air or gas escapes.

♦ Introduce the compressed air or the nitrogen through the serv‐

ice connection.

♦ The quick-release coupling adapter for service connection can

be fitted with a modified charging hose -A- (e.g. with a 5/8"-18

UNF thread, depending on the thread of the quick-release

coupling adapter) and a suitable adapter -B- to connect to the

workshop compressed air system ⇒ page 174 . To ensure no

moisture, oil or other contaminants can enter the refrigerant

circuit from the workshop compressed air system, use, for ex‐

ample, a supplementary combination fine filter element with

an oil, dirt and water separator as normally used in paint

shops. Install it between the compressed air system and the

charging hose -A- ⇒ Workshop equipment catalogue .

♦ Using the manifold gauge with pressure reducer for nitrogen

(maximum reduced pressure: 15 bar) -1- you can connect a

full nitrogen gas cylinder -3- via a charging hose -2- (e.g. with

5/8"-18 UNF threaded connection) to the service connection,

to which a quick-release coupling adapter is connected, of a

closed refrigerant circuit. ⇒ page 174

– Slowly increase pressure in refrigerant circuit to a maximum

of 15 bar.

lk

WARNING

♦ Maximum permissible working pressure: 15 bar

♦ When searching for leaks using nitrogen, work only with a

pressure reducer for nitrogen cylinders.

– Search for leak by sound, which is created by the escaping

gas. Use Ultrasonic tester - V.A.G 1842- to ease localisation

of sounds.

– Press nitrogen out of refrigerant circuit using cleaned and

dried compressed air. Nitrogen must not enter the service cyl‐

inder. This prevents the service cylinder from being filled with

condensable gases.

– Rectify leak.

– Evacuate again and observe the vacuum display over a period

of hours. Charging may be done only when vacuum is main‐

tained.

♦ If a leak is present of a size where no or very little air is drawn

in and the air conditioner service station can create sufficient

vacuum. The vacuum gauge does not increase or increases

very slowly after switching the air conditioner service station

off, this indicates there may be a very small ingress of air and

the vacuum is lost.

– Charge circuit with 100 g of refrigerant and search for the pos‐

sible leak using an electronic leak tester and rectify fault as

necessary ⇒ page 58 or add an approved UV contrast sub‐

stance to the refrigerant and search for the possible leak in the

circuit using leak detector system VAS 6201 or later model and

rectify fault as necessary ⇒ page 59 .

6. Detecting leaks in refrigerant circuit

57

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

– Evacuating refrigerant circuit if necessary ⇒ page 49

– Evacuate refrigerant circuit and observe the vacuum gauge

over a period of hours. Charging may be done only when vac‐

uum is maintained.

6.2

Searching for leaks in refrigerant circuits

using leak detector - V.A.G 1796-

lk

Note

Small leaks can be detected with, for example, an electronic leak

detector.

– Evacuate refrigerant circuit using an air conditioner service

station ⇒ page 50 .

Note

♦ If a larger leak is detected during the evacuation process, de‐

termine cause and rectify as described ⇒ page 50 .

♦ If during the evacuation process no leak is detected or a very

small leak is detected that but cannot be located, proceed as

follows ⇒ page 56 .

♦ Refrigerant gas is quickly dispersed by air motion. Therefore

drafts must be avoided during a search for leaks.

♦ If the refrigerant circuit is completely empty, charge with about

10% of refrigerant capacity (sticker R134a or vehicle-specific

workshop manual).

Leak detection:

– Prepare leak detector for operation according to its operating

instructions.

– Always hold probe tip under location of suspected leak.

If the rate of clicks rises or a howl occurs, depending on model, a

leak has been found (see operating instructions for leak detector).

58

Rep. gr.00 - Technical data

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

6.3

Detecting leaks in refrigerant circuit us‐

ing leak detecting system - VAS 6196-

or leak detecting system - VAS 6201- or

a later model

Note

Small leaks can be detected with, for example, an UV leak de‐

tector additive.

– Evacuate refrigerant circuit using an air conditioner service

station ⇒ page 50 .

Note

♦ If a larger leak is detected during the evacuation process, de‐

termine cause and rectify as described ⇒ page 50 .

♦ If during the evacuation process no leak is detected or a very

small leak is detected that but cannot be located, proceed as

follows ⇒ page 56 .

♦ Refrigerant gas is quickly dispersed by air motion. Therefore

drafts must be avoided during a search for leaks.

♦ If the refrigerant circuit is completely empty, charge with about

10% of refrigerant capacity (sticker R134a or vehicle-specific

workshop manual).

lk

Leak detecting system - VAS 6196-

or

Leak detecting system - VAS 6201- or later model

1 - Hand pump with low-pressure service hose, service cou‐

pling and non-return valve - VAS 6201/1-

2 - Cartridge - VAS 6201/2-

3 - Cleaning solution - VAS 6201/3-

4 - UV leakage detector lamp - VAS 6201/4-

5 - UV absorbing eye protection - VAS 6201/6-

6 - Label - VAS 6201/7-

7 - Tube

VAS 6201/8

8 - Protective gloves - VAS 6201/9-

6. Detecting leaks in refrigerant circuit

59

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Injecting leak detecting additive to an empty refrigerant circuit

lk

The cartridge -A- contains 15.4 ml of leak detecting additive (one

unit -B- equates to 2.5 ml).

– Assemble hand pump - VAS 6201- item -1- and cartridge item

-2- -VAS 6201/2- .

– Connect filler hose - VAS 6201/8- ( ⇒ page 59 item -7-) to hand

pump.

– Open service valve of hand pump.

60

Rep. gr.00 - Technical data

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

The leak detecting additive can be injected into the empty refrig‐

erant circuit via an open circuit connection.

– Open an easily assessable connection in the refrigerant cir‐

cuit.

– Cover area of connection with foil or absorbent paper.

– Hold tube upwards

– Turn T-bar of hand pump until the leak detecting additive flows

out of the tube.

3

–

Inject 2.5 ± 0.5 ml (millilitre = cm ) of leak detecting additive

into the refrigerant circuit.

Note

Note the following, if a leak detecting additive has been injecte_ld_k

during a previous repair of the refrigerant circuit, only inject new

leak detecting additive if the refrigerant machine oil has been re‐

placed. If only some of the refrigerant machine oil was replaced

then only the respective amount of leak detecting additive should

be injected. If for example 100 ml of machine oil was replaced on

a vehicle with 250 ml of refrigerant machine oil, inject only 1 ml

3

(cm ) of leak detecting additive.

– Renew O-rings at opened connection.

– Reassemble refrigerant circuit again.

– Attach a label, close to the service connection, which has in‐

formation showing that the refrigerant circuit has been injected

with a leak detecting additive.

– Evacuate and fill the refrigerant circuit as per specifications

⇒ page 51 and ⇒ page 50 .

– Start air conditioning system.

Note

The air conditioning system must be operated for at least 60 mi‐

nutes to ensure that the injected leak detecting additive is distrib‐

uted throughout the entire refrigerant circuit (air conditioner

compressor must run). The leak may become visible after a short

period, but this depends on the size of the leak.

– Use UV lamp VAS 6196/4 to search for the leak in the refrig‐

erant circuit ⇒ page 63 .

Note

Using cleaning solution - VAS 6201/3- , clean the engine com‐

partment and, if necessary, the components of the refrigerant

circuit, to remove leak detection additive residue left from the re‐

pair work.

6. Detecting leaks in refrigerant circuit

61

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Injecting leak detecting additive to a charged refrigerant circuit

Note

♦ Note the following, if a leak detecting additive has been injec‐

ted during a previous repair of the refrigerant circuit, only inject

new leak detecting additive if the refrigerant machine oil has

been replaced. If only some of the refrigerant machine oil was

replaced then only the respective amount of leak detecting

additive should be injected. If for example 100 ml of machine

oil was replaced on a vehicle with 250 ml of refrigerant ma‐

3

chine oil, inject only 1 ml (cm ) of leak detecting additive.

♦ A small amount of leak detecting additive remains in the serv‐

ice connection. Carefully remove the remains as this will help

to prevent these remains being falsely identified as a leak

when leak detection is carried out in the future.

The cartridge -A- contains 15.4 ml of leak detecting additive (one

unit -B- equates to 2.5 ml).

lk

– Switch off ignition.

– Remove sealing cap from service connection on the low-pres‐

sure side of the refrigerant circuit.

– Assemble hand pump - VAS 6201- item -1- and cartridge item

-2- -VAS 6201/2- .

Note

Ensure the hose of the hand pump is completely filled with leak

detecting additive.

– Fit the quick release coupling to the service connection of the

low-pressure side and open the service coupling by turning the

hand wheel. Hold hose upwards and turn T-bar of hand pump

until the leak detecting additive starts to flow out of the tube.

– Cover area of service connection on vehicle with foil or ab‐

sorbent paper.

– Turn T-bar of hand pump and inject 2.5 ± 0.5 ml (millilitre =

3

cm ) of leak detecting additive into the refrigerant circuit.

62

Rep. gr.00 - Technical data

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

– Close the service coupling and remove it from the service

connection.

– Remove the remains of the leak detecting additive from the

service connection, with for example, absorbent paper.

– Seal service connection using the sealing cap.

– If necessary, clean the area of the service connection using

the cleaning solution.

lk

– Attach a label, close to the service connection, which has in‐

formation showing that the refrigerant circuit has been injected

with a leak detecting additive.

– Start air conditioning system.

Note

The air conditioning system must be operated for at least 60 mi‐

nutes to ensure that the injected leak detecting additive is distrib‐

uted throughout the entire refrigerant circuit (air conditioner

compressor must run). The leak may become visible after a short

period, but this depends on the size of the leak.

– Use UV lamp VAS 6196/4 to search for the leak in the refrig‐

erant circuit ⇒ page 63 .

Note

Using cleaning solution - VAS 6201/3- , clean the engine com‐

partment and, if necessary, the components of the refrigerant

circuit, to remove leak detection additive residue left from the re‐

pair work.

Searching for leaks in the refrigerant circuit using UV lamp VAS

6196/4

WARNING

Do not look into the UV lamp.

Do not point the UV lamp at another person.

6. Detecting leaks in refrigerant circuit

63

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦ The air conditioning system must be operated for at least

60 minutes to ensure that the injected leak detecting additive

is distributed throughout the entire refrigerant circuit (air con‐

ditioner compressor must run). The leak may become visible

after a short period, but this depends on the size of the leak.

♦ For leaks on the evaporator, the additive can wash off with the

condensed water and leak out from the condensed water

drain-off. As the evaporator is not accessible on the majority

of models without a great amount of pre-preparation, a check

of the condensed water drain point can indicate a leaking

evaporator. The additive must have been in the refrigerant cir‐

cuit for a long time to make this possible.

♦ The eye protect is not only required to protect the eyes, it also

amplifies the illumination of the additive under the UV lamp.

♦ Independent of the accessibility to the various components of

the refrigerant circuit, it may become necessary to remove

certain components from the vehicle (e.g. bumper or air filter).

– Position the vehicle in a darker area of the workshop (in day‐

light or under strong lighting the effect of the UV lamp is greatly

lk

reduced).

– Check the accessibility to the various components of the re‐

frigerant circuit and remove components in the vicinity of the

refrigerant circuit that obstruct the view of the respective circuit

components (e.g. sound insulation and bumper).

– Protect eyes with protective glasses.

– Connect UV lamp to a 12 V battery (vehicle battery). Ensure

that it is connected to the correct terminals.

– Switch on UV lamp and illuminate components of the refriger‐

ant circuit. Locations where leaking refrigerant along with

refrigerant oil and leak detecting additive can leak out, light-up

(fluorinate) under UV light.

Note

♦ The leak detection additive can be allowed to remain in the

refrigerant circuit.

♦ Using cleaning solution - VAS 6201/3- , clean the engine com‐

partment and, if necessary, the components of the refrigerant

circuit, to remove leak detection additive residue left from the

repair work.

64

Rep. gr.00 - Technical data

Detectingleaksinrefrigerantcircuit for Your Volkswagen LT Van Second Generation (1996-2006)

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