LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 870 (Engine Mechanical) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Oil Pump Cleaning and Inspection

Oil Pump Cleaning and Inspection

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
  1. Clean all parts of sludge, oil, and varnish by soaking in cleaning solvent.
  2. Inspect for foreign material and determine the source of the foreign material.
  3. Inspect the pump housing and cover for the following conditions:
    • Cracks or casting imperfections
    • Scoring (3)
    • Damaged threads
  4. Do not attempt to repair the pump housing.

    Replace the pump housing.

  5. Inspect the oil pump gears for the following conditions:
    • Scoring (1)
    • Excessive wear (2)
    Fig 1: Inspecting Pump Housing, Cover And Oil Pump Gears For Scoring And Excessive Wear
    G01500774Courtesy of GENERAL MOTORS CORP.
  6. Inspect the idler shaft for looseness or scoring (4).

    If loose or damaged, replace the oil pump.

  7. Inspect the drive gear shaft for looseness or scoring (5).
  8. Inspect the pressure regulator valve for the following conditions:
    • Scoring
    • Sticking

    Burrs may be removed using a fine oil stone.

  9. Inspect the pressure regulator valve spring for the following conditions:
    • Loss of tension
    • Bending
  10. Inspect the suction pipe and screen assembly for the following conditions:
    • Looseness

      If the suction pipe is loose, bent or has been removed, replace the pump body cover and suction pipe.

    • Broken wire mesh or screen
    Fig 2: Inspecting Pressure Regulator Valve For Scoring And Spring For Loss Tension
    G01500775Courtesy of GENERAL MOTORS CORP.
  11. Measure the oil pump gear lash. Install the gears, and measure in several places.
    Fig 3: Measuring Oil Pump Gear Lash
    G01500776Courtesy of GENERAL MOTORS CORP.
  12. Measure the oil pump housing gear pocket (1, 2).
    Fig 4: Measuring Oil Pump Housing Gear Pocket
    G01500777Courtesy of GENERAL MOTORS CORP.
  13. Measure the oil pump gears (1, 2).
    Fig 5: Measuring Oil Pump Gears
    G01500778Courtesy of GENERAL MOTORS CORP.

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

  14. Measure the oil pump gear side clearance.
    Fig 6: Measuring Oil Pump Gear Side Clearance
    G01500779Courtesy of GENERAL MOTORS CORP.