GM Service Manual Online
For 1990-2009 cars only

Problem

Action

Loose drive gear or pulley

Important: Do not back off the crankshaft nut in order to align the cotter pin and the castellated nut. Some compressors do not use castellated nuts. Do not use impact wrenches.

    • The pulley on the gear must be completely seated and the crankshaft nut must be tight.
    • If the compressor crankshaft surface or the keyway is damaged, the drive components are loose.
    • If damage to the compressor crankshaft is detected, replace the compressor.
    •  When installing the drive gear or pulley, torque the crankshaft nut to the appropriate torque specifications.

Excessively worn drive couplings or gears

  1. Inspect drive gear and couplings and engine for excessive wear .
  2. Replace as necessary.
  3. Non-metallic gears should be replaced when the compressor is changed.

Compressor cylinder head or discharge line restrictions

  1. Inspect the compressor discharge port and discharge line for carbon build-up.
  2. If carbon is detected, check for proper cooling to the compressor.
  3. Inspect the discharge line for kinks and restrictions.
  4. Replace discharge line as necessary.

Worn or burned out bearings

Check for proper oil pressure in the compressor.

Specification

    • The minimum required oil pressure with the engine idling is 103 kPa (15 psi).
    • Check for excessive oil temperature. The temperature should not exceed 116°C (240°F).

Faulty compressor

Replace or repair the compressor after determining none of the preceding installation defects exist.