GM Service Manual Online
For 1990-2009 cars only

Draining Procedure

    Important: Drain and measure as much of the refrigerant oil as possible from the removed compressor.

  1. Drain the oil from both the suction and discharge ports of the removed compressor into a clean, graduated container.
  2. Rotate the compressor shaft to assist in draining the compressor.


    Object Number: 821777  Size: SH
  3. Measure and record the amount of oil drained from the removed compressor.
  4. This measurement will be used during installation of the replacement compressor.

    Important: During the oil removal procedure, the condition of the oil should be evaluated. Compressor oil never breaks down unless something is wrong with the compressor or air conditioning (A/C) system. If one or more of the following conditions exist, replace the compressor and receiver dehydrator.

  5. Inspect oil drained from removed compressor. Refer to Air Conditioning Compressor Oil Diagnosis.
  6. Properly discard the used refrigerant oil.

Balancing Procedure

    Important: The refrigerant oil in the A/C system must be balanced during compressor replacement.

  1. The replacement compressor is shipped with 120 ml (4.0 oz) of refrigerant oil.

  2. Object Number: 821777  Size: SH
  3. Compare the amount of refrigerant oil recorded during compressor removal to the amount of refrigerant oil shipped in the replacement compressor. If the amount of refrigerant oil drained and recorded from the removed compressor is:
  4. • Less than 120 ml (4.0 oz), leave the 120 ml (4.0 oz) in the replacement compressor.
    • More than 120 ml (4.0 oz), add to the compressor the difference between the 120 ml (4.0 oz) and the amount drained.