For 1990-2009 cars

1. Clean all parts of sludge, oil, and varnish by soaking in carburetor cleaner or cleaning solvent.
2. Inspect for foreign material and determine the source of the foreign material.
3. Inspect the oil pump housing and engine front cover for the following conditions:

• | Cracks or casting imperfections

• | Scoring

• | Damaged threads

4. Do not attempt to repair the oil pump housing. Replace the oil pump housing if damage is found.
5. Inspect the oil pump gears for damage.
6. Measure the inner oil pump gear tip clearance in several places.
7. Measure the outer oil pump gear tip clearance in several places.

Important: When deciding oil pump serviceability based on end clearance, consider depth of the wear pattern in the pump cover.

8. Measure the oil pump gear side clearance.
9. Inspect the pressure regulator valve for the following conditions:

• | Scoring

• | Sticking

• | Burrs -- Burrs may be removed using a fine oil stone.

10. Inspect the pressure regulator valve spring for loss of tension or bending. Replace the pressure regulator spring if damaged.
11. Inspect the oil pump pipe pickup tube and screen assembly for the following conditions:

• | Looseness -- If the oil pump pipe pickup tube is loose or bent, replace the oil pump pipe pickup tube.

• | Broken wire mesh or screen

• | Inspect the O-ring seal at the base of the oil pump pickup tube for damage.