For 1990-2009 cars

1. With the vehicle on a level surface, allow adequate drain down time of 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.
3. Run the engine, 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 moisture or unburned fuel mixtures

• | Improper oil viscosity for the expected temperature

• | Incorrect or malfunctioning oil pressure sender

• | Incorrect or malfunctioning oil pressure gage

• | Plugged oil filter

• | Malfunctioning oil bypass valve

6. Remove the oil pressure sender or another engine block oil gallery plug.
7. Install an oil pressure gage and measure the engine oil pressure.
8. Compare the readings to the specifications. Refer to Engine Mechanical Specifications.
9. If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions:

• | Oil pump worn or dirty

• | Refer to Oil Pump Disassemble.

• | Oil pump-to-engine front cover bolts loose

• | Refer to 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.

• | Cracked, porous or restricted oil galleries

• | Oil gallery plugs missing or incorrectly installed

• | Refer to Engine Block Assemble.

• | Broken lash adjusters