For 1990-2009 cars

1. With the vehicle on a level surface, allow adequate drain down time, 2-3 minutes, and measure for the proper engine oil level. An overfull oil level causes aeration within the oil.
2. Add the recommended grade engine oil GM P/N 12345610, (Canadian P/N 993193), or equivalent, and fill the crankcase until the oil level measures FULL on the oil level indicator.
3. Operate the engine and verify low or no oil pressure on the vehicle oil pressure gage or oil indicator lamp.

Listen for a noisy valve train or knocking noise.

4. Inspect for the following conditions:

• | Engine oil diluted by moisture or unburned fuel mixtures

• | Improper engine oil viscosity for the expected temperature

• | Incorrect or faulty oil pressure gage sensor

• | Incorrect or faulty oil pressure gage

• | Plugged oil filter

• | Malfunctioning oil filter bypass valve

5. Remove the oil pressure gage sensor or another engine block oil gallery plug.
6. Install an oil pressure gage and measure the engine oil pressure.
7. If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions:

• | Oil pump worn or dirty

• | Malfunctioning oil pump pressure relief valve

• | Oil pump screen loose, plugged, or damaged

• | Excessive bearing clearance or worn bearings

• | Cracked, porous, or restricted oil galleries

• | Engine block oil gallery plugs missing or incorrectly installed

• | Broken valve lifters