Engine Oil Pressure: Testing and Inspection

Oil Pressure Diagnosis and Testing

Special Tools

EN-21867-850 - Oil Pressure Gauge Adapter

For equivalent regional tools, refer to Special Tools (Special Tools).

* With the vehicle on a level surface, allow adequate drain down time of 2-3 minutes and measure for a low oil level.
Add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
* Run the engine, and verify low, or no oil pressure on the vehicle gauge or light.
Listen for a noisy valve train or a knocking noise.
* Inspect for the following:

- Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter
- Oil diluted by moisture or unburned fuel mixtures
- Improper oil viscosity for the expected temperature
- Incorrect or malfunctioning oil pressure sender
- Incorrect or malfunctioning oil pressure gauge
- Plugged oil filter
- Malfunctioning oil bypass valve

* Remove the oil pressure sender or another engine block oil gallery plug.
* Install EN-21867-850 - adapter and an oil pressure gauge and measure the engine oil pressure.
* Compare the readings to specifications. Refer to Engine Mechanical Specifications (LAF) (Service Limits & General Specifications).
* If the engine oil pressure is below specifications, inspect the engine for one or more of the following:

- Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter
- Oil pump worn or dirty
Refer to Oil Pump Disassemble (37. Oil Pump Disassemble).
- Oil pump-to-engine front cover bolts loose
Refer to Engine Front Cover and Oil Pump Installation (58. Engine Front Cover and Oil Pump 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
Refer to Crankshaft and Bearing Cleaning and Inspection (25. Crankshaft and Bearing Cleaning and Inspection).
- Cracked, porous or restricted oil galleries
- Oil gallery plugs missing or incorrectly installed
Refer to Engine Block Assemble (45. Engine Block Assemble).
- Broken lash adjusters