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Oil Pump Cleaning and Inspection

WARNING: This page is about a different car, the 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  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:
    • Cracks
    • Scoring
    • Porous or damaged casting
    • Damaged threads
    • Excessive wear
    Fig 1: Oil Pump Cover And Gears
    G01764564Courtesy of GENERAL MOTORS CORP.
  4. Inspect the pressure regulator valve for the following damage:
    • Scoring
    • Sticking in the bore
    • Burrs
    • Foreign material
  5. Inspect the pressure regulator spring for loss of tension or bending. Replace the pressure regulator spring if damaged.
  6. Inspect the oil pump gears for the following conditions:
    • Chipping
    • Galling
    • Scoring
    • Excessive wear
  7. Measure the inner oil pump gear tip clearance. 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.
    Fig 2: Measure The Inner Oil Pump Gear Tip Clearance
    G01764565Courtesy of GENERAL MOTORS CORP.
  8. Measure the outer oil pump gear diameter clearance. If the outer oil pump gear diameter clearance is greater than 0.381 mm (0.015 in) the oil pump must be replaced.
    Fig 3: Measure The Outer Oil Pump Gear Diameter Clearance
    G01764566Courtesy of GENERAL MOTORS CORP.
  9. Measure the oil pump gear end clearance.
  10. Measure the pressure regulator valve-to-bore clearance. If the pressure regulator valve-to-bore clearance is greater than 0.076 mm (0.003 in) the oil pump must be replaced.
    Fig 4: Measure The Oil Pump Gear End Clearance
    G01764567Courtesy of GENERAL MOTORS CORP.