Oil Pressure Diagnosis and Testing

Oil Pressure Diagnosis and Testing

Tools Required

* J 21867 Pressure Gage
* J 42907 Oil Pressure Tester

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 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, 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 antifreeze
^ Foamy oil




6. Remove the oil filter.




7. Install the J 42907 onto the oil filter adapter.




8. Install the 1/8 NPT fitting from the J 21867 into the port on the J 42907.




9. Install the J 21867 flexible hose to the J 42907.
10. Run the engine and measure the engine oil pressure.
11. Compare the readings to Engine Mechanical Specifications.
12. If the engine oil pressure is below specifications, inspect the engine for 1 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.
^ Oil pump pressure relief valve malfunction.
^ Oil outlet tube bolts loose or missing, O-rings damaged or missing, mounting flange damaged and/or tube broken or damaged.
^ Engine bearing clearance excessive.
^ Cracked, porous, or restricted oil galleries.
^ Oil gallery plugs missing or incorrectly installed.
^ Valve lifters broken. Repair, as necessary.
^ Crankshaft balancer bolt missing, loose or under-torqued.
13. 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.