Compressor HVAC: Description and Operation

Air Conditioning

A/C Compressor and Clutch Assembly

NOTE: The internal A/C compressor components are not serviced separately. The A/C compressor is serviced only as an assembly. The A/C clutch disc and hub, A/C compressor pulley and A/C clutch field coil are serviceable.

The A/C compressor has the following characteristics:

- A non-serviceable shaft seal.
- A pressure relief valve is installed in the bottom rear of the A/C compressor to protect the refrigerant system against excessively high refrigerant pressures. The A/C pressure relief valve is a separate component and can be removed and installed separately from the A/C compressor.
- The A/C compressor uses PAG oil or equivalent. This oil contains special additives required for the A/C compressor.
- The A/C compressor oil may have some slightly dark-colored streaks while maintaining normal lubricant properties. This is normal for this A/C compressor because of break-in wear that can discolor the oil.
- Use the refrigerant oil adding procedure specified for this vehicle when installing a new A/C compressor.

When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch plate and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate. When battery voltage is removed from the A/C compressor clutch field coil, springs in the clutch plate and hub assembly move the clutch plate away from the A/C clutch pulley.