For 1990-2009 cars

### Oil Pressure Test

1. Remove the oil pressure switch (1) from the engine block.
2. Install a pressure gauge in place of the oil pressure switch.
3. Start the engine and run at idle until normal operating temperature is reached.
4. Raise the engine speed to 4000 RPM and measure the oil pressure.

Normal Oil Pressure
330-430 kPa (47-61 psi) at 4000 RPM

5. If the oil pressure is below specification refer to the following table.
6. Stop the engine.
7. Remove the pressure gauge.
8. Install the oil pressure switch.

Tighten
Tighten the oil pressure switch to 14 N·m (10 lb ft).

9. Run the engine and inspect for oil leaks from the oil pressure switch.

#### Oil Pressure Diagnosis

Problem | Action
--- | ---
The oil level is low. | Fill the oil to the FULL mark on the oil level indicator.
The idle speed is low or unstable. | Refer to Engine Controls.
The oil pressure switch is incorrect or malfunctioning. | Replace the oil pressure switch.
The oil pressure indicator is incorrect or malfunctioning. | Replace the oil pressure indicator.
The oil viscosity is improper. | Use oil of the proper viscosity for the expected temperature.
The oil is diluted with one of the following materials:

• | Moisture

• | An unburned fuel mixture

Fill with new oil.

The oil pump is worn or dirty. | Replace or clean the oil pump as necessary.
The oil filter is plugged. | Replace the oil filter.
The oil pickup screen is loose or plugged. | Adjust or replace the screen as necessary.
The oil pickup tube has a hole. | Replace the tube.
The oil pickup tube O-ring is faulty. | Replace the O-ring.
The bearing clearance is excessive. | Replace the bearings as necessary.
The oil galleries display one of the following conditions:

• | Cracked

• | Porous

• | Restricted

Repair or replace the block as necessary.

The gallery plugs or cylinder head oil jet are missing or incorrectly installed. | Install the plugs / oil jet and repair as necessary.
The oil pump pressure regulator valve is malfunctioning. | Inspect and replace the valve.
The camshaft or cylinder head is worn or poorly machined. | Replace the camshaft and or the cylinder head.
The valve guides are worn. | Replace the guides.