Engine Oil Pressure: Testing and Inspection

Oil Pressure Diagnosis and Testing

^ Tools Required
- J 21867 Pressure Gage
- J 42907 Oil Pressure Testing Tool





1. With the vehicle on a level surface, run the vehicle for a few minutes, allow adequate drain down time of 2 - 3 minutes, and measure the 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, approximately 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:
^ Oil diluted by water or glycol - anti freeze
^ Foamy oil
6. Remove the oil filter and install the J 42907.
7. Install J 21867 or equivalent to the J 42907.
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to Engine Mechanical Specifications (LR4 VIN V) Engine Mechanical Specifications (LM7 VIN T) Engine Mechanical Specifications (LQ4 VIN U).
10. If the engine oil pressure is below specifications, inspect the engine for one or more of the following conditions:
^ Oil pump worn or dirty
^ Oil pump-to-engine block bolts loose
^ 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
^ Broken valve lifters Repair as necessary.
11. If the oil pressure reading on the J 21867 or equivalent is within specifications, inspect for the following conditions:
^ Plugged or incorrect oil filter and/or malfunctioning oil bypass valve
^ Malfunctioning oil pressure gage or sensor Repair as necessary.