Oil Pressure Testing

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required

J 21867 Pressure Gauge and Hose
J 42907 Oil Pressure Tester Adapter

If the vehicle has low oil pressure perform the following tests.

Check the oil level.
Raise the vehicle and remove the oil filter.
Assemble the plunger valve in the large hole of J 42907 (1) base and the hose in the small hole of J 42907 (1) base. Connect the J 21867 (2) to the end of the hose.

Fig 1: Installing J 42907 And J 21867 To Engine Block

Courtesy of GENERAL MOTORS CORP.

Insert the flat side of the rubber plug in the bypass valve without depressing the bypass valve itself.
Install J 42907 (1) on the filter mounting pad.
Start the engine and check the overall oil pressure and the oil pressure switch. The engine should be at operating temperature before checking the oil pressure. The oil pressure should be approximately 85 kPa (12 psi) at 1200 rpm using 5W30 engine oil.
If adequate oil pressure is indicated, check the oil pressure switch.
If a low reading is indicated, press the valve on the tester base 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 would indicate a faulty pump.