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Refrigerant Circuit, Flushing with Refrigerant R134a: Notes
2009 Audi A6 BaseSECTION Notes
WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2009 Audi S4, 2009 Audi A4, 2008 Audi S4, 2008 Audi RS 4, and 2008 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
- Flush refrigerant circuit using refrigerant R134a in order to force out moisture and other contaminants (e.g. shavings from a malfunctioning compressor) as well as old refrigerant oil as efficiently as possible, without wasting refrigerant, without the need for extensive assembly work and without endangering the environment.
Flush the refrigerant circuit:
- In the event of dirt or other contamination in the circuit.
- If vacuum reading is not maintained on evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in refrigerant circuit).
- If refrigerant circuit has been left open for longer than normal (e.g. following an accident).
- If pressure and temperature measurements in the refrigerant circuit indicate the likelihood of moisture.
- In the event of doubt about the amount of refrigerant oil in the circuit.
- The A/C compressor had to be replaced on account of internal damage (e.g. noise or no output).
- If stipulated by the vehicle-specific repair manual following replacement of certain components.
Tools required
- A/C service station with flushing equipment VAS 6336 or A/C service station with flushing equipment VAS 6337 (these A/C service stations include the additional function for "flushing the refrigerant circuit" and the required equipment for flushing refrigerant circuits) → Workshop equipment and special tools catalog
- Adapter case for VW/Audi passenger cars VAS 6338/1 → Adapter for Assembly of Flushing Circuits and → Workshop equipment and special tools catalog
NOTE:
- If there is neither of the mentioned A/C service stations, it is possible to flush the refrigerant circuit using flushing equipment for refrigerant circuits VAS 6336/1 or flushing equipment for refrigerant circuits VAS 6337/1 depending on the A/C service station used, flushing must then be performed manually. → Process of flushing (process is performed automatically according to the A/C service station program)
- On vehicles with threaded connections to the refrigerant circuit, the adapters V.A.G 1785/7 and adapters V.A.G 1785/8 from the adapter case for VW/Audi passenger cars VAS 6338/1 can be used; on vehicles with threaded connections to compressor and to reservoir, the adapter V.A.G 1785/8 is needed twice.
- There is also a fill hose VAS 6338/31 with connections 5/8 -18 UNF and large inner diameter in short version (commercially available) included in the adapter case for VW/Audi passenger cars VAS 6338/1.
Preparation
- Discharge A/C refrigerant system.
- Remove compressor → 87 - Air conditioning
On a vehicle with restrictor and reservoir
- Remove restrictor (vehicle-specific) and reconnect lines → 87 - Air conditioning
- Remove reservoir (vehicle-specific) and reconnect the lines (use adapters and fill hose VAS 6338/31 from the adapter case for VW/Audi passenger cars VAS 6338/1 ) → Adapter for Assembly of Flushing Circuits , → 87 - Air conditioning
NOTE:
- The reservoir could be flushed but because of its large internal volume it will take too much refrigerant, the reservoir would ice-up too much when extracting the refrigerant, the refrigerant would evaporate too slowly and extraction would be extended too much.
On a vehicle with expansion valve and fluid reservoir
- Remove fluid reservoir (vehicle-specific) and reconnect the lines (use adapters and fill hose VAS 6338/31 from the adapter case for VW/Audi passenger cars VAS 6338/1 ) → Adapter for Assembly of Flushing Circuits , → 87 - Air conditioning
NOTE:
- The fluid reservoir can be flushed depending on the version (remove dryer cartridge if necessary) → Adapter for Assembly of Flushing Circuits , → 87 - Air conditioning
- The fluid reservoir connected to the condenser (e.g. on model Audi A3 from model year 2004) remains installed during flushing (it can be flushed due to its design and is only replaced after flushing) → Adapter for Assembly of Flushing Circuits and → 87 - Air conditioning
- Remove dryer cartridge from vehicles with dryer partridge in fluid reservoir that is connected to the condenser (vehicle-specific), and re-seal opening on fluid reservoir → 87 - Air conditioning
- Remove expansion valve (vehicle-specific) and install one adapter from the adapter case for VW/Audi passenger cars VAS 6338/1 → Adapter for Assembly of Flushing Circuits , → 87 - Air conditioning .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.