Compressor HVAC: Description and Operation

A/C Compressor

• Depending on time period of production and on engine, compressor construction type may vary. Refer to => [ Refrigerant Circuit Component Overview ] Refrigerant Circuit Component Overview and the Electronic Parts Catalog.

• For vehicles with 6 cylinder and 8 cylinder FSI engine, the A/C compressor may be dismantled and removed from the bracket only when the refrigerant circuit is emptied and open. Refer to => [ Compressor ] Compressor.

• At start of production, vehicles without a high voltage system have A/C compressors manufactured by "Denso" (type "6 SEU 14" on vehicles with a 4-cylinder or 6-cylinder engine, and type "7 SEU 17" on vehicles with an 8-cylinder engine). Compressors from other manufacturers may also be installed at a later time. Refer to Electronic Parts Catalog (ETKA).

• These A/C compressors are available as replacement parts with different oil fill capacities, therefore note capacity on A/C compressor. Refer to the exact part number shown in Electronic Parts Catalog (ETKA).

• Depending on A/C compressor type, different refrigerant oil fill capacities are designated for the refrigerant circuit. The reason for the different oil capacities in the A/C compressor for an otherwise identical refrigerant circuit lies in the design of the A/C compressor itself, note these oil capacities. Too much oil in the circuit leads to higher pressures and reduces cooling performance of the system. Too little oil may lead to lubrication problems in the compressor.

• If a new mechanically-driven compressor has been installed or new refrigerant oil has been put into these A/C compressors (for example, after flushing refrigerant circuit), the A/C compressor must be turned by hand approximately 10 turns. This ensures that the A/C compressor is not damaged when activated.

• After installing a new electrically-driven A/C compressor ( electrical A/C compressor (V470) ) or filling new refrigerant oil. Operate this A/C compressor using "compressor cut-in" in "Guided Fault Finding". Refer to Vehicle Diagnostic Tester in A/C system and Battery Control.

• Mechanically-Driven A/C compressor, removing and installing, 4 cylinder engine, refer to => [ A/C Compressor ] A/C Compressor.

• A/C Compressor, removing and installing, 6 cylinder, refer to => [ A/C Compressor ] A/C Compressor.

• A/C Compressor, removing and installing, 8 cylinder engine, refer to RS => [ A/C Compressor ] A/C Compressor or RS5=> [ A/C Compressor ] A/C Compressor.