Refrigerant Circuit, Flushing With Refrigerant R134A: Notes
Special tools and workshop equipment required
- Robinair A/C Service Unit ROB134APF or Rinsing device for refrigerant circuits VAS6337/1. The auxiliary function "Flush refrigerant circuit" and the refrigerant circuit flushing device required for it are present on these A/C service stations.
- VW/Audi passenger vehicle set adapter chest VAS 6338/1. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT and Workshop equipment and special tools information.
- Commercial vehicle set adapter chest VAS 6338/50. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT and Workshop equipment and special tools information.
- If it is suspected that chemicals were added to the refrigerant circuit to seal leaks, do not connect the A/C service station and do not extract the refrigerant.
- Chemicals that seal leaks in the coolant circuit form deposits that affect the function of the A/C system and lead to failure of the A/C system and the A/C service station.
- Inform that customer that there are substances in the A/C system that are no approved by Volkswagen. This A/C system cannot be drained or serviced in the workshop.
VW does not approve the use of chemicals to seal leaks in the refrigerant circuit.
Chemicals used to seal leaks in the refrigerant circuit often react with air and the moisture in it. They cause deposits in the refrigerant circuit and the A/C service station and malfunctions in valves and other components that they come in contact with. These deposits cannot be removed completely from the components, even by flushing.
Chemicals used to seal leaks in the refrigerant circuit usually cannot be detected from outside. The label that should be applied to identify it is often missing. Therefore be careful when working with if you do not know its service history.
- Refrigerant circuit must be flushed with refrigerant R134a in order to force out contaminants (such as abraded material from a malfunctioning A/C compressor) as well as old refrigerant oil as efficiently and as cleanly as possible and without the need for extensive work.
The procedure for flushing the refrigerant circuit is displayed in Volkswagen Service Net; Volkswagen TV; API Online; or Volkswagen TV Net; API / PKW under the book title Body and the program from June 8, 2005 Refrigerant Circuit, Flushing, Golf Plus.
The refrigerant circuit should be flushed with refrigerant R134a if
- dirt or other contamination is in the refrigerant circuit.
- vacuum reading is not maintained on evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in refrigerant circuit).
- refrigerant circuit has been left open for longer than normal (for example following an accident).
- the pressure and temperature measurements in the refrigerant circuit indicate the likelihood of moisture in the circuit.
- in the event of doubt about the amount of refrigerant oil in the circuit. If the A/C compressor should be reinstalled, the refrigerant should be drained from the compressor via the oil drain plug. To facilitate this, the ribbed belt pulley or magnetic clutch plate on the A/C compressor should be rotated by hand. After flushing, the entire quantity of refrigerant oil specified by Maintenance, Diagnosis should be added to the refrigerant circuit (50 grams directly in the A/C compressor). Note additional oil quantity for systems with a 2nd evaporator.
- A/C compressor had to be replaced on account of internal damage (for example noise or no output).
- stipulated by the vehicle-specific repair information following replacement of certain components.
If neither of the two A/C service stations listed above are available for use in the workshop, Refrigerant Circuit Flushing Device VAS 6336/1 or Refrigerant Circuit Flushing Device VAS 6337/1 (depending on the workshop A/C service station version) (minimum 7 kg refrigerant R134a in refrigerant bottle) can also be used to flush the refrigerant circuit. However, the flushing procedure must then be performed manually. Refer to SEQUENCE OF FLUSHING PROCEDURE .
In vehicles with screw-connections on refrigerant circuit, Adapter V.A.G 1785/1 up to Adapter V.A.G 1785/8 from VW/Audi passenger vehicle set adapter chest VAS 6338/1 or Commercial vehicle set adapter chest VAS 6338/50 may be used. In vehicles with screw-connections on A/C compressor and on accumulator, two of the Adapters V.A.G 1785/8 are required.
A Charging hose VAS 6338/31 with 5/8 -18 UNF connections and large internal diameter can be found in the adapter chests in order to be able to bridge components (it is commercially available).
Preparation
-- Discharge refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .
-- Remove A/C compressor. Refer to [For engine(s) BLV, CCTA, CBFA] Removal and Installation .
On a vehicle with restrictor and reservoir:
-- Remove restrictor (specific to vehicle) and reconnect refrigerant pipes to each other. Refer to [For engine(s) BLV, CCTA, CBFA] Removal and Installation .
-- Remove reservoir (specific to vehicle). Refer to [For engine(s) BLV, CCTA, CBFA] Removal and Installation and connect refrigerant pipes to each other (to do this, use adapter and Charge hose VAS 6338/31) from VW/Audi passenger vehicle set adapter chest VAS 6338/1. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
The reservoir could be flushed, but it requires too much refrigerant due to its large volume. When this refrigerant is extracted, the reservoir ices up severely and this prolongs the extraction process significantly.
On a vehicle with expansion valve and fluid reservoir:
-- Remove fluid reservoir. Refer to [For engine(s) BLV, CCTA, CBFA] Removal and Installation (specific to vehicle, not required for all vehicles) and connect refrigerant pipes to each other (for this, use adapters and Charging hose VAS 6338/31). Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
-- Remove expansion valve. Refer to [For engine(s) BLV, CCTA, CBFA] Removal and Installation (specific to vehicle) and install the adapter for it. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .