Engine Oil Pressure: Testing and Inspection

Oil Pressure Diagnosis and Testing


Tools Required
* J 21867 Pressure Gage
* EN-47971 Oil Pressure Gage 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 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 gauge 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 EN-47971 (1).
7. Install J 21867 (2), or equivalent, to the EN-47971 (1).
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to Engine Mechanical Specifications (L76) (Specifications) .
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.
Refer to Oil Pump Cleaning and Inspection (Overhaul) .
* Oil pump-to-engine block bolts loose.
Refer to Oil Pump, Screen and Crankshaft Oil Deflector Installation (Overhaul) .
* Oil pump screen loose, plugged, or damaged. Refer to Oil Pump Cleaning and Inspection (Overhaul) .
* Oil pump screen O-ring seal missing or damaged. Refer to Oil Pump Cleaning and Inspection (Overhaul) .
* Oil filter loose or a leaking or damaged gasket. Refer to Oil Filter, Adapter, and Pan Cover Installation (Overhaul) .
* Malfunctioning oil pump pressure relief valve. Refer to Oil Filter, Adapter, and Pan Cover Installation (Overhaul) .
* Above acceptable bearing clearance.
* Cracked, porous, or restricted oil galleries.
* Oil gallery plugs missing or incorrectly installed.
Refer to Engine Block Plug Installation (Overhaul) .
* Broken valve lifters. Refer to Valve Lifter Replacement (Valve Lifter Replacement) .
Repair as necessary.
* Improper operation of the active fuel management oil pressure relief valve. Refer to Cylinder Deactivation (Active Fuel Management) Oil Pressure Relief Valve Diagnosis and Testing (Component Tests and General Diagnostics) .

11. If the oil pressure reading on the J 21867 (2), or equivalent, is within specifications, inspect for the following conditions:

* Plugged or incorrect oil filter and/or malfunctioning oil filter bypass valve. Refer to Engine Oil and Oil Filter Replacement (Service and Repair) .
* Malfunctioning engine oil pressure sensor or switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement (Service and Repair) .