Look for the oil pressure sending unit on the block or the cylinder head on the V-6 or V-8 models.
OIL PRESSURE TEST
Check for proper oil pressure at the sending unit passage with an externally mounted mechanical oil pressure gauge (as opposed to relying on a factory installed dash-mounted gauge). A tachometer may also be needed, as some specifications may require running the engine at a specific rpm.
- With the engine cold, locate and remove the oil pressure sending unit.
- Following the manufacturer's instructions, connect a mechanical oil pressure gauge and, if necessary, a tachometer to the engine.
- Start the engine and allow it to idle.
- Check the oil pressure reading when cold and record the number. You may need to run the engine at a specified rpm, so check the specifications.
- Run the engine until normal operating temperature is reached (upper radiator hose will feel warm).
- Check the oil pressure reading again with the engine hot and record the number. Turn the engine OFF.
- Compare your hot oil pressure reading to specification. If the reading is low, check the cold pressure reading against the chart. If the cold pressure is well above the specification, and the hot reading was lower than the specification, you may have the wrong viscosity oil in the engine. Change the oil, making sure to use the proper grade and quantity, then repeat the test.
Low oil pressure readings could be attributed to internal component wear, pump related problems, a low oil level, or oil viscosity that is too low. High oil pressure readings could be caused by an overfilled crankcase, too high of an oil viscosity or a faulty pressure relief valve.