Oil Pressure Diagnosis and Testing. Pontiac Grand Prix 2003

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2003 🢒 Grand Prix 🢒 Engine 🢒 Engine Mechanical - 3.1L 🢒 Oil Pressure Diagnosis and Testing

The following conditions may cause low or no oil pressure:

•	Low oil level

Fill to the full mark on the oil level indicator.

•	Incorrect or malfunctioning oil pressure switch

Replace the oil pressure switch.

•	Incorrect or malfunctioning oil pressure gage

Replace the oil pressure gage.

•	Improper oil viscosity or diluted oil

-	Install oil of proper viscosity for expected temperature.

-	Install new oil if the oil is diluted.

•	A worn or dirty oil pump

Clean or replace the oil pump.

•	A plugged oil filter

Replace the oil filter.

•	A loose or plugged oil pickup screen

Replace the oil pickup screen.

•	A hole in the oil pickup tube

Replace the oil pickup tube.

•	Excessive bearing clearance

Replace the bearings.

•	Cracked, porous, or plugged oil gallery

Repair or replace the engine block.

•	Missing or improperly installed gallery plugs

Install or repair the plugs as needed.

•	A stuck pressure regulator valve

-	Inspect the pressure regulator valve for sticking in the bore.

-	Inspect the bore for scoring and burrs.

•	A worn or poorly machined camshaft

Replace the camshaft.

•	Worn valve guides

Repair the valve guides as needed.

J 25087-C Oil Pressure Tester

If the vehicle has low oil pressure complete the following steps:

Inspect the oil level.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Remove the oil filter.
Assemble the plunger valve in the large hole of the J 25087-C base. Insert the hose in the small hole of the J 25087-C base. Connect the gauge to the end of the hose.
Insert the flat side of the rubber plug in the bypass valve without depressing the bypass valve.
Install the J 25087-C on the filter mounting pad.
Start the engine.
Inspect the overall oil pressure, the oil pressure switch, and for noisy lifters. Ensure that the engine is at operating temperature before inspecting the oil pressure. The oil pressure should be approximately 414 kPa (60 psi) at 1,850 RPM using 5W-30 engine oil.
If adequate oil pressure is indicated, test the oil pressure switch.
If a low reading is indicated, press the valve on the tester base in order to isolate the oil pump and/or its components from the lubricating system. An adequate reading at this time indicates a good pump and the previous low pressure was due to worn bearings, etc. A low reading while pressing the valve indicates a faulty pump.