Refrigerant Circuit, Blowing Through
For vehicles that have refrigerant lines with no threads for connecting the A/C Adapter Set -V.A.G 1785-. Use, for example, an air blow gun with a rubber mouth piece or an adapter from the Refrigerant Circuits Adapter Set 1:VAS 6338/1 for blowing through the individual components. When using an air blow gun with a rubber mouthpiece, take special care not to damage the connections (bending or scratching).
Evaporator is to be blown out via the connection for low pressure line (large diameter) with the expansion valve or restrictor removed.
Always clean (flush or blow) components in the opposite direction of the refrigerant flow.
Check the expansion valve and replace if dirty or corroded.
Locate any components with dark, sticky deposits on them that cannot be removed with compressed air and either clean (flush) the components using refrigerant R134a or replace them.
Thin, light gray deposits on the inside (of pipes) do not impair the function of the components.
After blowing through, always replace the receiver/dryer or the reservoir and restrictor. Replace the dryer cartridge on condensers that have one installed in the integrated receiver/dryer.
For condensers with an integrated receiver/dryer or dryer cartridge that cannot be replaced separately or is not available as a replacement part, the condenser must be replaced after cleaning (flushing). Refer to the appropriate Electronic Parts Informatio and Refrigerant Circuit (vehicle-specific repair information).
Depending on the version, there may be an additional filter element on receiver/dryers where the dryer cartridge can be replaced separately. This filter element must be replaced with the dryer cartridge if necessary.
After blowing through the refrigerant circuit:
-- Replace these vehicle-specific components (restrictor and reservoir, expansion valve and receiver/dryer or dryer cartridge). Refer to Refrigerant Circuit (vehicle-specific repair information) and the appropriate Electronic Parts Information.
-- Replace the A/C compressor, depending on the complaint (refer to A/C Compressor (vehicle-specific repair information) and the appropriate Electronic Parts Information), or drain the rest of the refrigerant oil from the removed A/C compressor (Refer to REFRIGERANT CIRCUIT COMPONENTS, REPLACING ; replacing refrigerant circuit components) and fill with the specified amount of new refrigerant oil (Refer to APPROVED REFRIGERANT OILS AND REFRIGERANT OIL CAPACITIES ; approved refrigerant oils and capacities).
There is a specific prescribed amount of refrigerant oil in the replacement A/C compressor. If the vehicle has two evaporators, a certain amount of refrigerant oil must also be added to the circuit if necessary. Refer to Refrigerant Circuit (vehicle-specific repair information) and Refer to APPROVED REFRIGERANT OILS AND REFRIGERANT OIL CAPACITIES (Approved Refrigerant Oils and Capacities).
If the A/C compressor is not to be replaced, the quantity of refrigerant oil in the A/C compressor must be topped off according to the prescribed capacity (pour out the refrigerant oil and refill the prescribed quantity into the A/C compressor or refrigerant circuit). Refer to REFRIGERANT CIRCUIT COMPONENTS, REPLACING (replacing refrigerant circuit components) and Refer to APPROVED REFRIGERANT OILS AND REFRIGERANT OIL CAPACITIES (approved refrigerant oils and capacities).
-- Completely reassemble the refrigerant circuit again. Refer to Refrigerant Circuit (vehicle-specific repair information).
-- Evacuate and fill the refrigerant circuit according to specification. Refer to REFRIGERANT CIRCUIT, EVACUATING WITH A/C SERVICE STATION and Refer to REFRIGERANT CIRCUIT, CHARGING WITH A/C SERVICE STATION .
-- Start the A/C system according to specification. Refer to A/C SYSTEM, STARTING AFTER CHARGING REFRIGERANT CIRCUIT (vehicle-specific repair information) and Refer to A/C SYSTEM, OPERATING AFTER CHARGING .