GM Service Manual Online
For 1990-2009 cars only

Add the refrigerant oil to the system when the components are replaced in the following order:

  1. All of the compressors. Drain the oil. Measure the oil.
  2. 1.1. Drain the oil out of the following components:
       • The suction port of the replacement compressor
       • The discharge port of the replacement compressor
       • The suction port of the old compressor
       • The discharge port of the old compressor
    1.2. Remove the compressor crankcase drain bolt. Drain the oil from the compressor crankcase.
             1.2.1. If less than 60 ml (1 oz) is drained, add 60 ml (2 oz) to the new compressor.
             1.2.2. If more than 30 ml (1 oz) is drained, add the same amount that was drained to the new compressor.
             1.2.3. Up to 120 ml (4 fluid ounces) of oil may collect in the crankcase. When replacing a compressor, drain and measure the oil in the old compressor crankcase. Discard the old oil after recording the amount.

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    1.3. Install the compressor crankcase drain bolt.

    Tighten
    Tighten the compressor crankcase bolt to 20 N·m (15 lb ft).

  3. Accumulator.
  4. Add 105 ml (3.5 oz) to the new accumulator.

  5. Evaporator.
  6. Add 90 ml (3 oz) oil.

  7. Condenser.
  8. Add 30 ml (1 oz) oil.

  9. Refrigerant oil loss due to a large leak:
  10. • If the refrigerant charge is abruptly lost due to a large refrigerant leak, approximately 90 ml (3 oz) of refrigerant oil is carried out of the system with the refrigerant. Any failure that causes an abrupt refrigerant discharge experiences this oil loss. Failures that allow the refrigerant to seep or bleed off over time do not experience this oil loss.
    • Upon replacement of a component that caused a large refrigerant leak, add 90 ml (3 oz) of refrigerant oil plus the required amount of oil for the particular component (as outlined above).

Add the oil directly to the replaced component if possible. If the oil cannot easily be added to the replaced part, add the oil to the accumulator.