A/C - Refrigerant Circuit Cleaning Procedure
87 Cleaning of the air conditioning refrigerant circuit
87 11 23
2018162/3
September 20, 2011.
Supersedes Technical DIAGNOSIS AND REPAIR Group 87 number 08 - 13 dated December 5, 2008 for reasons listed below.
Affected Vehicles
Condition
Repeat repairs of air conditioning system. Debris was dispersed throughout the refrigerant circuit after air conditioning component damage. During
the first repair, the refrigerant circuit was not thoroughly cleaned. The debris has contaminated the new components.
Technical Background
In cases where an air conditioning system component (such as a compressor or other system component) has failed and debris from the compressor
or component is circulated throughout the refrigerant circuit, the refrigerant circuit must be cleaned of any and all debris or damage to the
replacement components will result.
The cleaning method until now has been disassembly of each part of the refrigerant circuit, blowing out the debris with compressed air, and drying
the components with nitrogen. This was ineffective for this purpose and labor intensive. A more thorough and less time consuming method is
flushing the circuit with refrigerant.
Production Solution
Not applicable.
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 327
Warranty
Required Parts and Tools
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service
manuals for the latest information.
Service
Service
Tools
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 328
Use the ROB134APF Air Conditioning Service System with VAS 6337/1A Air Conditioning System Flushing Device for effective refrigerant
handling and air conditioning circuit flushing after air conditioning component failure.
Now air conditioning system refrigerant recovery, evacuation, recharge and refrigerant circuit cleaning after component failure can be performed
with a single servicing station.
The VAS 6338/1 Adapter Set for Refrigerant Circuits. Along with an additional adapter (VAS 6338/33 for the front expansion valve bypass for the
Audi Q7) this kit contains the adapters necessary to complete a thorough flush operation of a contaminated circuit.
ElsaWeb contains the technical information for each model regarding the necessary adapter applications and connections of the servicing station for
the flush operation. See Elsa Web >> Heating, Ventilation Air Conditioning >> Refrigerant R134A-Servicing >> 87 Air Conditioning >>
Refrigerant Circuit >> Refrigerant Circuit, Flushing with Refrigerant R134A.
All other refrigerant recovery, evacuation and recharge operations are performed using the usual procedure specified in ElsaWeb. An operations
manual will accompany each servicing station that will describe operation of the unit.
Procedure
1. If an air conditioning component has been diagnosed as the root cause of the failure and this component is suspected of releasing debris through
the circuit, continue the diagnosis to determine if this is the case.
2. Turn the power to the servicing station on and begin by recovering the refrigerant from the system through the normal service fittings.
Tip: During the entire process avoid interrupting the power to the station. The stations internal memory will keep a log of all operations and can
conveniently be recalled and printed. If the power is interrupted, the station will lose the memory of the process, and the oil volume recovered, oil
volume added, refrigerant volume recovered, etc. will have to be manually determined.
3. Disconnect the service hoses. The VAS 6338/1 adapters will be used to bypass the following:
^ Compressor.
^ Receiver drier (depending on model).
^ Expansion valve.
If vehicle is equipped with a restrictor, remove the restrictor and reconnect the line.
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 329
4. Once the appropriate adapters are in place, connect the service station to the vehicle through the air conditioning compressor hoses. The flushing
attachment ports are labeled on the flusher.
This connection strategy allows for a system flush in the opposite direction of the normal refrigerant flow.
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 330
The flush program will begin with an evacuation of the system and a rate of rise test. This is necessary to test the integrity of the connections
before the flush cycles begin. If the rate of rise test passes, the program will proceed into the flush cycles. These cycles will occur automatically in
succession.
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 331
The debris is then rinsed from the circuit and contained within the filtration in the flusher. After the flush program, the system will be evacuated.
5. After the system is evacuated, disconnect the station.
Audi Q7 with four zone climate control
If the vehicle is an Audi Q7 with four zone climate control, the flush process will be repeated for the additional air conditioning unit in the rear
according to the repair information in ElsaWeb.
1. Separate the front and rear air conditioning Systems for individual rinse operations.
The VAS 6338/1 contains the necessary adapters to separate the systems for the individual rinse operations.
Audi A4 Quattro Sedan (8K2) L4-2.0L Turbo (CAEB) Page 332
2. Bypass the rear expansion valve with an adapter from the VAS 6338/1.
3. When complete, remove any adapters that were installed from the VAS 6338/1.
4. Install components in need of replacement.
5. Connect the station in the usual manner through the service fittings and perform the normal evacuation, oil fill and refrigerant recharge operations.
6. Recall and print a log of the job. Attach the log to the repair order.
