GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 1797371  Size: SH
  1. Remove the primary timing chain and crankshaft sprocket. Refer to Primary Camshaft Drive Chain and Sprockets Replacement.
  2. Remove the three bolts (1) attaching the oil pump (2).
  3. Remove the oil pump assembly.

Disassembly Procedure


    Object Number: 1797414  Size: SH

    Note: There are no serviceable components within the oil pump. Disassemble the pump only to diagnose oil related concern. A disassembled oil pump must not be reused, it must be replaced. The primary timing chain lower guide is not serviced separately and is part of the oil pump assembly. If it is removed from the pump assembly, the guide and the pump must be replaced.

  1. Remove the 2 bolts (1) attaching the primary timing chain lower guide (2) and remove the guide.

  2. Object Number: 1797415  Size: SH
  3. Remove the 7 bolts (2) attaching the oil pump cover to the oil pump housing (1) and remove the cover from the housing.

  4. Object Number: 1797417  Size: SH
  5. Remove the inner gerotor ring (1).
  6. Remove the outer gerotor ring (2).

  7. Object Number: 1797422  Size: SH
  8. Remove the clip (1), retaining the oil relief valve cap (2).
  9. Remove the cap, spring (3) and plunger (4) from the oil pump housing.

Cleaning Procedure

  1. Clean the oil pump components with non-corrosive solvent.
  2. Dry the oil pump components with compressed air.

Inspection Procedure


    Object Number: 1797429  Size: SH
  1. Inspect the oil pump housing for damage.

  2. Object Number: 1797430  Size: SH
  3. Inspect the oil pump cover for damage.

  4. Object Number: 1797431  Size: SH
  5. Inspect the inner drive gear for damage. If inner surface damage is found, ensure the crankshaft is also inspected.

  6. Object Number: 1797438  Size: SH
  7. Inspect the outer driven gear for damage.

  8. Object Number: 1797448  Size: SH
  9. Inspect the oil pump relief valve components for debris or damage.

  10. Object Number: 1797452  Size: SH
  11. Inspect the primary camshaft chain lower guide for damage. If replacement of the primary camshaft chain lower guide is required, replace the entire oil pump assembly as the primary camshaft chain lower guide is not serviceable separately.
  12. If debris or damage is present within the oil pump, further inspection of all of the engine components is required.

Assembly Procedure

Note: As there are no serviceable components within the oil pump, a disassembled oil pump must be replaced.

Installation Procedure


    Object Number: 1797371  Size: SH
  1. Align the oil pump gerotor with the crankshaft flats and fit the oil pump assembly to the engine block.
  2. Align the pump body (2) with the mounting holes in the cylinder block.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the oil pump bolt (1) and tighten attaching bolt to 23 N·m (17 lb  ft).
  5. Install the primary timing chain. Refer to Primary Camshaft Drive Chain and Sprockets Replacement.