GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 21867 Pressure Gage
    • J 36648-A Adapter
  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. Add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator, if required.
  3. Run the engine briefly, 10-15 seconds, and verify low or no oil pressure on the vehicle gage or light.
  4. Listen for a noisy valve train or a knocking noise.
  5. Inspect for the following conditions:
  6. • Foamy oil
    • Slow idle speed
    • Plugged oil filter
    • Oil diluted by the following items:
       - Water
       - Engine coolant
       - Unburned fuel mixtures
    • Malfunctioning oil filter bypass valve
    • Incorrect or faulty oil pressure gage
    • Incorrect or faulty oil pressure gage sensor
    • Improper engine oil viscosity for the expected temperature

    Object Number: 1252146  Size: SH
  7. Remove the oil pressure gage sensor.

  8. Object Number: 1252147  Size: SH
  9. Install the J 36648-A  (1) in place of the oil pressure sensor.
  10. Connect the J 21867  (2) to the J 36648-A .
  11. Start the engine and then allow the engine to reach normal operating temperature.
  12. Measure the engine oil pressure.
  13. Specification

    • The minimum oil pressure at idle should be 30 kPa (4.35 psi).
    • The minimum oil pressure at 2000 rpm should be 250 kPa (35 psi).
  14. If the engine oil pressure is below specifications, inspect the engine for one or more of the following conditions:
  15. • Loose oil filter adapter bolts
    • Missing or damaged oil filter adapter O-ring seal or seals
    • Worn or dirty oil pump
    • Loose oil pump-to-engine block bolts
    • Loose, plugged, or damaged oil pump screen
    • Missing or damaged oil pump screen O-ring seal
    • Damage or leak in the oil pump screen suction tube
    • Malfunctioning oil pump pressure regulator valve
    • Missing or incorrectly installed oil gallery plugs
    • Loose camshaft intermediate drive shaft bolts
    • Excessive bearing clearance for the following items:
       - Connecting rod or rods
       - Crankshaft
       - Camshaft or camshafts
       - Camshaft intermediate drive shaft sprocket
    • Cracked, porous or restricted oil galleries
    • Broken valve lifters
  16. Repair or replace the components as necessary.