GM Service Manual Online
For 1990-2009 cars only

    Warning: Refer to Cleaning Solvent Warning in the Preface section.


    Object Number: 26160  Size: SH
  1. Use a suitable solvent to clean the oil pump.
  2. Remove all old gasket material from the engine front cover and from the engine block.
  3. Inspect the oil pump cover and the engine front cover for the following damage:
  4. • Cracks
    • Scoring
    • Porous or damaged casting
    • Damaged threads
    • Excessive wear
  5. Inspect the pressure regulator valve for the following damage:
  6. • Scoring
    • Sticking in the bore
    • Burrs
    • Foreign material
  7. Inspect the pressure regulator spring for loss of tension or bending. Replace the pressure regulator spring if damaged.
  8. Inspect the oil pump gears for the following conditions:
  9. • Chipping
    • Galling
    • Scoring
    • Excessive wear

    Object Number: 38819  Size: SH
  10. Measure the inner oil pump gear tip clearance.
  11. If the clearance for the inner oil pump gear tip is greater than 0.152 mm (0.006 in) the oil pump must be replaced.


    Object Number: 38820  Size: SH
  12. Measure the outer oil pump gear diameter clearance.
  13. If the outer oil pump gear diameter clearance is greater than 0.381 mm (0.015 in) the oil pump must be replaced.


    Object Number: 36663  Size: SH
  14. Measure the oil pump gear end clearance.
  15. Measure the pressure regulator valve-to-bore clearance.
  16. If the pressure regulator valve-to-bore clearance is greater than 0.076 mm (0.003 in) the oil pump must be replaced.