GM Service Manual Online
For 1990-2009 cars only

    Object Number: 166656  Size: SH
  1. Remove the five screws and the gear plate (1) from the oil pump body.

  2. Object Number: 166669  Size: SH
  3. Remove the outer and inner pump gears from the oil pump body.
  4. Inspect the following for the excessive wear or damage:
  5. • The oil pump outer gear (1)
    • The oil pump inner gear (2)
    • The gear plate
    • The oil pump body

    Object Number: 166685  Size: SH
  6. Measure the radial clearance between the oil pump outer gear (1) and the oil pump body using a feeler gage.
  7. Replace the oil pump outer gear and/or oil pump if the clearance exceeds 0.310 mm (0.0122 in).


    Object Number: 166682  Size: SH
  8. Measure the side clearance between the oil pump gears and a straightedge using a feeler gage (1).
  9. Replace the gears if the clearance exceeds 0.15 mm (0.0059 in).


    Object Number: 166669  Size: SH
  10. Apply a thin coat of new engine oil to the following parts:
  11. • The oil pump inner gear (2)
    • The oil pump outer gear (1)
    • The oil seal lip
    • The inside surface of the oil pump body
    • The inside surface of the gear plate
  12. Install the oil pump outer and inner gears to the oil pump body.
  13. Important: Ensure that the oil pump gears operate smoothly after installation of the gear plate.

  14. Install the gear plate to the oil pump body. Secure the gear plate with five screws.