GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 21867 Pressure Hose and Gauge Assembly
    • J 42907 Oil Pressure Testing Tool

    Object Number: 416607  Size: SH
  1. With the vehicle on a level surface, run the vehicle for a few minutes, allow adequate drain down time (2-3 minutes) and measure for a low oil level.
  2. If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
  3. Run the engine briefly (10-15) seconds and verify low or no oil pressure on the vehicle gauge or light.
  4. Listen for a noisy valve train or a knocking noise.
  5. Inspect for the following:
  6. • Oil diluted by water or glycol (anti freeze)
    • Foamy oil
  7. Remove the oil filter and install the J 42907 .
  8. Install J 21867 or equivalent to the J 42907 .
  9. Run the engine and measure the engine oil pressure.
  10. Compare the readings to Engine Mechanical Specifications .
  11. If the engine oil pressure is below specifications, inspect the engine for one or more of the following:
  12. • Oil pump worn or dirty
    • Refer to Oil Pump Clean and Inspect .
    • Oil pump-to-engine block bolts loose
    • Refer to Oil Pump, Screen and Crankshaft Oil Deflector Installation .
    • Oil pump screen loose, plugged, or damaged
    • Oil pump screen O-ring seal missing or damaged
    • Malfunctioning oil pump pressure regulator valve
    • Excessive bearing clearance
    • Cracked, porous, or restricted oil galleries
    • Oil gallery plugs missing or incorrectly installed
    • Refer to Engine Block Plug Installation .
    • Broken valve lifters
    • Repair as necessary
  13. If the oil pressure reading on the J 21867 or equivalent is within specifications, inspect for the following:
  14. • Plugged or incorrect oil filter and/or malfunctioning oil bypass valve
    • Malfunctioning oil pressure gauge or sensor
    • Repair as necessary