Audi A4: Refrigerant Circuit, Flushing

  Note

• In the case of vehicles on which the refrigerant lines have no threads for connection of Adapter Set -1785-. Use for example a flushing gun with rubber end piece or an adapter from the Refrigerant Circuits Adapter Set 1 -VAS6338/1- for blowing through the individual components. When using a flushing gun with rubber end piece, take special care not to damage the connections (crushing or scratching).
• Evaporator is to be flushed via the connection for low-pressure pipe (large diameter) after removing expansion valve or removing restrictor.
• Always clean (flush or blow) components in direction opposite to refrigerant flow.
• Check expansion valve and replace if dirty or corroded.
• Locate any components on which dark, sticky deposits cannot be removed with compressed air and either clean (flush) them using refrigerant R134a or replace them.
• Thin, light grey deposits on the inside of pipes do not impair the function of the components.
• After flushing, always replace receiver/dryer or reservoir and restrictor. Replace the dryer cartridge on condensers that have one installed in the integrated receiver/dryer.
• If the receiver/dryer or dryer cartridge is integrated in the condenser, then they cannot be replaced separately and the condenser must be replaced. Refer to the Parts Catalog and → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual).
• Receivers/dryers where it is possible to replace the dryer cartridge have an additional filter, which must also be replaced with the dryer cartridge.

After Blowing through the Refrigerant Circuit:

- Replace these components depending on equipment (restrictor and reservoir, expansion valve and receiver/dryer or dryer cartridge). Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual) and the Parts Catalog.

- Replace the A/C compressor, depending on its condition. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; A/C Compressor (vehicle-specific repair manual) and Parts Catalog or drain the rest of the refrigerant oil still inside the removed A/C compressor (replace the refrigerant circuit components) and will new refrigerant. Refer to → Chapter "Refrigerant Circuit Components, Replacing" and → Chapter "Approved Refrigerant Oils and Capacities" (Approved Refrigerant Oils and Capacities).

  Note

• There is a defined and prescribed amount of refrigerant oil in the replacement compressor. If the vehicle has two evaporators, then there refrigerant circuit requires a specific quantity of refrigerant oil. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual) and → Chapter "Approved Refrigerant Oils and Capacities". (Approved Refrigerant Oils and Capacities).
• If the A/C compressor is not be replaced, the quantity of refrigerant oil in the A/C compressor must be topped off to the prescribed capacity (tilt the refrigerant oil out and refill the prescribed quantity into the A/C compressor or refrigerant circuit). Refer to → Chapter "Refrigerant Circuit Components, Replacing" (replacing refrigerant circuit components) and → Chapter "Approved Refrigerant Oils and Capacities". Approved Refrigerant Oils and Capacities).

- Reassemble the refrigerant circuit completely. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual).

- Evacuate and recharge the refrigerant circuit according to specification. Refer to → Chapter "Refrigerant Circuit, Discharging with Service Station" and → Chapter "Refrigerant Circuit, Charging with Service Station".

- Start up A/C system according to specification. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; Refrigerant Circuit; A/C System, Starting Operation after Filling Refrigerant Circuit (vehicle-specific repair manual) and → Chapter "A/C System, Operating after Charging".

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