Cleaning (flushing) refrigerant circuit with refrigerant R134a — AUDI

🧭 Before you start

Fits: Audi A5 (8T, 2007–2016), Audi Q5 (8R, 2008–2017), Audi A2 (8Z), Audi A3 (8L, 1996–2003), Audi A4 B5 (8D), Audi A4 B6/B7 (8E), Audi A4 B9 (8W, 2015–), Audi R8 (4S, 2015–), Audi A5 Cabriolet (8F), Audi A6 C5 (4B), Audi A8 D2 (4D), Audi A8 D3 (4E, 2002–2010), Audi A3 (8P, 2003–2012), Audi A4 Cabriolet B6/B7 (8H), Audi TT Mk1 (8N), Audi A6 C6 (4F, 2004–2011), Audi A4 B8 (8K, 2007–2015), Audi Q7 (4L, 2005–2015), Audi A3 (8V, 2012–2020), Audi Q7 (4M, 2015–), Audi A8 D4 (4H, 2010–2017), Audi TT Mk2 (8J, 2006–2014), Audi A6/A7 C7 (4G, 2011–2018), Audi A1 (8X, 2010–2018), Audi Q3 (8U, 2011–2018); platform codes 8C, 4A, 8G, 85, FV, 42, 83, 84, 4X

• Opens: refrigerant (A/C)
• Renewed: filter, them with adapters

Don't miss

• 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 positive pressure in the refrigerant circuit).

📋 Procedure

1. ⚠ When working on a vehicle with the ignition switched on or while the drive system is active, the engine can start unexpectedly and exhaust fumes can cause a health hazard in closed rooms. Moving parts can trap or draw in parts of the body and/or clothing (safety hazard). Before switching on the ignition, perform the following steps:Move selector lever to position PActivate parking brake Switch off ignitionOpen bonnetConnect battery charger (e.g. VAS 5095A) to jump-start connections of 12 V electrical system Switch on ignition — 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 60AVAS 5904 in battery standby mode Electrical system; General information27Battery; Charging battery and Electrical system93General warning instructions for work on the high-voltage system.
2. For test and measurement work that requires the vehicle's drive system to be active (READY) or the ignition to be switched 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 control 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).] [Note: Audi does not permit the use of chemical substances (sealing additives) to seal leaks in the refrigerant circuit.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 cannot be completely removed from the components affected (even by cleaning/flushing). The refrigerant circuit can therefore only be repaired by renewing all the components which have come into contact with this substance.Chemical substances (sealing additives) for sealing leaks in the refrigerant circuit are normally not outwardly apparent and the identification stickers which should be affixed for this purpose are usually non-existent. Therefore, act with caution when working on a vehicle whose past you are not familiar with.]
3. ⚠ If there is a possibility that chemical substances (sealing additives) for sealing leaks have been added to the refrigerant circuit to be flushed, do not connect the air conditioner 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. — In there is any dirt or similar in the circuit.
4. If vacuum reading is not maintained on evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in refrigerant circuit)
5. If the refrigerant circuit has been left open for longer than normally required for repairs (e.g. following an accident).

6. If pressure and temperature measurements in the refrigerant circuit indicate the likelihood of moisture.
7. If there are doubts about the amount of refrigerant oil in the refrigerant circuit.
8. If the air conditioner compressor has to be renewed on account of internal damage (e.g. noise or no output). [Note: For vehicles with an electrically driven air conditioner compressor, see the notes on renewing the electric air conditioning compressor V470 (damage to the electronic system of the air conditioner compressor does not always mean that the refrigerant circuit has to be cleaned) If a defective air conditioner compressor is replaced by a compressor 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 .]
9. If stipulated by the vehicle-specific Workshop Manual after renewing certain components [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 kitElectronic parts catalogue, (Tools; Workshop equipment/tools; Air conditioning/heating) however this must then be performed manually. Use can be made for vehicles with screw connections at the refrigerant circuit of the adapterV.A.G 1785/7 and adapterV.A.G 1785/8 from the VW/Audi passenger vehicle adapter setVAS 6338/1. Two adaptersV.A.G 1785/8 are required for a vehicle with screw connections at the air conditioner compressor and reservoir.The adapter set for refrigerant circuitsVAS 6338/1 also contains a short filler hoseVAS 6338/31 with 5/8 -18 UNF connections and a large inside diameter (commercially available).]
10. Discharge the refrigerant circuit .
11. Remove air conditioner compressor Heating, air conditioning87Air conditioner compressor (vehicle-specific Workshop Manual).
12. Remove restrictor (vehicle-specific) and re-connect pipes Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).
13. Remove the reservoir (vehicle-specific) and re-connect the pipes (for this purpose, make use of an adapter and the charging hoseVAS 6338/31 from the VW/Audi passenger vehicle adapter setVAS 6338/1) , Heating, air conditioning87Refrigerant circuit; System overview - 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.]
14. Remove the receiver (vehicle-specific, not necessary with all vehicles) and re-connect the pipes (for this purpose, make use of an adapter and the charging hoseVAS 6338/31 from the VW/Audi passenger vehicle adapter setVAS 6338/1) , Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual). [Note: Depending on the design, the receiver can be flushed (if necessary, remove desiccant cartridge installed in receiver) , Heating, air conditioning87Refrigerant circuit; System overview - 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) and Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).In the case of condensers with an integrated receiver / desiccant cartridge which cannot be renewed separately or which are not available separately, the condenser is to be renewed after flushing. On these vehicles, the condenser is then to be renewed together with the receiver Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit 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 together with the desiccant cartridge.]
15. 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 conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).
16. Remove the expansion valve (vehicle-specific) and replace it with an adapter from the adapter set for refrigerant circuitsVAS 6338/1, Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).
17. In the case of vehicles with a shut-off valve, remove this valve and replace it with an adapter (or manual shut-off valve) from the VW/Audi passenger vehicle adapter setVAS 6338/1 (or a drilled-open shut-off valve), Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual). [Note: If there is no suitable adapter for the expansion valve (or shut-off valve) in the VW/Audi passenger vehicle adapter setVAS 6338/1, the removed expansion valve (or shut-off valve) can also be drilled open (the old expansion valve generally has to be renewed anyway and is therefore no longer needed).] [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 differing design. With version (A), the parts (B), (C) and (D) have to be removed for example. Then separate part (E) (control element) 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.]
18. ⚠ Take care not to damage the sealing surfaces at the expansion valve (or shut-off valve) when drilling it open.Otherwise, refrigerant will escape at damaged sealing surfaces. — Remove swarf remnants from the expansion valve after drilling open.
19. 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 evaporator is to be separated from the circuit of the first evaporator and flushed in a separate operation and Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).] [Note: A shut-off valve must be drilled out, for example, if there is no shut-off valveVAS 6338/42 available to flush the coolant circuit.]
20. Start by removing solenoid (A) and solenoid valve (B).
21. Drill open the shut-off valve (C) using a suitable bit (bit diameter e.g. 5.0 mm).
22. Remove swarf remnants produced during drilling of the bore (D) from the shut-off valve (C).
23. Re-install the solenoid valve (B) with the corresponding seal (E) in the drilled-open shut-off valve (C).
24. Check the amount of refrigerant in the air conditioner service station, it must contain at least 7 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 conditioner 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 cycle.]
25. Discharge the used oil container of the air conditioner service station.
26. Connect the supply hose (high-pressure side) of the air conditioner service station with an adapter to the low-pressure pipe to the air conditioner compressor (pipe with larger diameter) .
27. Connect the return hose (low-pressure or suction end) of the air conditioner service station to the outlet of the refrigerant circuit flushing attachment.
28. Connect the inlet of the refrigerant circuit flushing attachment with an adapter to the high-pressure line to the air conditioner compressor (line with smaller diameter) . [Note: The components are always (with the exception of the electric air conditioner compressor) flushed in the opposite opposite to the refrigerant flow during air conditioner operation .When flushing, impurities from the refrigerant circuit ingress into the refrigerant circuit flushing attachment and the air conditioner service station, where they are retained in the built-in filters and dryer. Depending on the nature of the impurities, renew these components more frequently as specified by the operating instructions for the air conditioner service station or the refrigerant circuit flushing attachment.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 flushing cycles (flushed vehicles). After flushing a severely contaminated refrigerant circuit (the refrigerant oil from the refrigerant 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 refrigerant oil and abrasion from the air conditioner compressor) accumulates at the inspection port of the refrigerant circuit flushing attachment. If applicable, clean this sight glass after flushing and flush the refrigerant circuit again in one operation as a check (one operation 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 replace them with adapters if applicable Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).Adapters for connection of air conditioner service station and for bridging certain refrigerant circuit components .]
29. Switch on the air conditioner service station and flush the refrigerant 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 operating instructions for the air conditioner service station Operating instructions for air conditioner service station.Depending on the version of the air conditioner service station, the used oil container may only hold approx. 125 cm 3 of refrigerant oil. If a system with a larger refrigerant oil quantity is to be flushed, it may be necessary to empty the used oil container after the first flushing operation in a flushing cycle.Observe the refrigerant flowing back out of the refrigerant circuit 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 attachment 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 necessary to perform flushing twice (two flushing cycles with three flushing operations each).]
30. On completion of flushing, check the inspection port(s) of the refrigerant circuit flushing attachment. If these are contaminated, they are to be cleaned if necessary in line with the operating instructions for the refrigerant circuit flushing attachment or air conditioner service station. Flushing is then to be performed again as a check (one operation with a duration of approx. 30 min. is sufficient) Operating instructions for air conditioner service station.
31. Check the pressure in the refrigerant circuit. There must not be any positive pressure in the refrigerant circuit (evacuate briefly again if necessary).
32. Detach the connections to the air conditioner service station from the vehicle refrigerant circuit (there must not be any positive pressure in the refrigerant circuit).
33. Renew the following vehicle-specific components: restrictor and reservoir, expansion valve and receiver / desiccant cartridge in the receiver Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual) and Electronic parts catalogue
34. Depending on the problem, renew the air conditioner compressor Heating, air conditioning87Air conditioner compressor (vehicle-specific Workshop Manual) and Electronic parts catalogue, or drain off the remaining refrigerant oil from the air conditioner compressor (removed earlier) (Renewing components of refrigerant circuit) and add the specified quantity of new refrigerant oil again (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 conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual) and (Approved refrigerant oils and refrigerant oil capacities).If the air conditioner compressor is not to be renewed, the refrigerant oil quantity in the air conditioner compressor 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) (Renewing refrigerant circuit components) and (Approved refrigerant oils and refrigerant oil capacities).]
35. Completely re-assemble the refrigerant circuit Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).
36. Evacuate and charge the refrigerant circuit as specified and .
37. Start up the air conditioner as specified Heating, air conditioning87Refrigerant circuit; Operating the air conditioning after filling the refrigerant circuit (vehicle-specific Workshop Manual) and

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