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For 1990-2009 cars only

SMU - Revised Compressor Oil Balancing Procedure

Subject:Revised Compressor Oil Balancing Procedure

Models:2002 Chevrolet TrailBlazer
2002 GMC Envoy
2002 Oldsmobile Bravada



This bulletin is being issued to revise the Compressor Oil Balancing Procedure in the Heating, Ventilation and Air Conditioning sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.

The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.

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. This measurement will be used during installation of the replacement compressor.
  4. 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 240 ml (8.0 oz) of refrigerant oil.

  2. Object Number: 821777  Size: SH
  3. Before installing the compressor, the refrigerant oil will have to be partially drained.
  4. 2.1. Refer to the amount of refrigerant oil recorded during the compressor removal.
    2.2. Subtract the amount recorded from the total system capacity. Refer to Refrigerant System Capacities.

    The difference between the total system capacity and the recorded amount is the calculated amount to be drained from the replacement compressor.

  5. Drain the calculated amount of refrigerant from the replacement compressor.