Audi A4 Owners & Service Manuals

Audi A4: A/C System Repair Information

  • Air conditioning systems designed for refrigerant R12 are only to be filled with refrigerant R134a if certain requirements are fulfilled. Refer to → Chapter "Refrigerant Circuit, Converting R12 to R134a and Servicing" and Repair manual: Air Conditioner with R12 Parts 2 and 3. This repair manual is only available in hard copy.
  • The refrigerant oils specifically developed for R134a and R12 refrigerant circuits are never to be mixed.
  • Service stations which come in contact with the refrigerant are only to be used for the intended refrigerant.
  • Components of R134a refrigerant circuits can be identified by their markings, green labels or design (such as different threads) to prevent interchanging with components designed for refrigerant R12.
  • A label indicating the refrigerant used is provided in the engine compartment on the lock carrier or in the plenum chamber.
  • Different refrigerants are never to be mixed.


When working on the refrigerant circuit, always heed the information given in the sections on "Safety measures". Refer to → Chapter "A/C System and Refrigerant R134a Safety Precautions" and "Basic rules for working on refrigerant circuit" → Chapter "Refrigerant Circuit, General Precautions".

Refrigerant Circuit, Converting R12 to R134a

CFC refrigerants are no longer used in the automotive industry.

Converting refrigerant circuits from R12 refrigerant to R134a refrigerant and servicing converted circuits

Refer to Repair Manual: Air Conditioner with Refrigerant R12 Parts 2 and 3 (This repair manual is only available in printed form).


     Using Service Station

     General Information

    Vehicles with a high-voltage system (hybrid vehicles) Extremely Dangerous Due to High-Voltage The high-voltage system is under high-voltage. Death or serious bodily injury by electric shock. - I

     Service Station, Important Usage Information

    Observe the following with regard to service station operation. Refer to the Parts Catalog (Tools; Special Tools and Equipment: A/C and Heating). - The filters and dryers installed must be repl


     Coolant Pump, Removing and Installing

    Removing - Remove the engine cover. Refer to → Servicing - 4-Cylinder 2.0L 4V TFSI Engine; Rep. Gr.10; Engine Cover; Engine Cover, Removing and Installing. - Drain the coolant. Refer to → Chapter "Coolant, Draining and Filling". - Disconnect the connectors -

     Adjusting Buffer, Removing and Installing

    Adjusting Buffer, Removing and Installing, Sedan Body Adjusting Buffer Removing - Turn the adjusting buffer -1- counter-clockwise -arrow- to remove. - Remove the adjusting buffer locking mechanism -2- from the threaded pin. Installing Install in reverse order of removal and note the fo

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