Genuine 1999 Pontiac Grand Prix Oil Pump

1999 Pontiac Grand Prix Oil Pump Parts Questions & Experts Answers

• Q:

  How to remove and reinstall the oil filter and oil pump in 3.8L V6 engine on 1999 Pontiac Grand Prix?

  Posted by Mercedezmario L.

  A:

  To remove the oil filter, disconnect the oil cooler lines (if equipped) and the oil pressure sensor electrical connector. Next, remove the timing chain cover and the oil pump cover-to-timing chain cover bolts, using a T-30 Torx driver for the screws. Lift out the cover and oil pump gears as an assembly. Clean the parts with solvent and dry them with compressed air if available, then inspect all components for wear and score marks, replacing any worn or damaged parts. Reinstall the gears in the timing chain cover, measuring the outer gear-to-housing clearance and the inner gear-to-outer gear clearance at several points with a feeler gauge. Use a dial indicator or straightedge and feeler gauges to measure the gear end clearance, and check for pump cover warpage by laying a precision straightedge across the cover. Compare the measurements to the specifications and replace all worn or damaged components with new ones. For installation, pack the pump cavity with petroleum jelly before installing the gears, ensuring the jelly is forced into every cavity to prevent loss of prime when the engine starts. Install the pump cover with a new gasket, as its thickness is critical for maintaining correct clearances, followed by the pressure regulator spring and valve. Finally, install the timing chain cover, the oil filter, check the oil level, start the engine, and verify correct oil pressure while looking for oil leaks at the timing chain cover.

  Answered by GM Parts Specialist Henry / Jul 26, 2026