GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 25087-C Oil Pressure Test Kit

If you suspect low oil pressure, check the pressure on the vehicle.

  1. Check the oil level.
  2. Raise the vehicle and remove the oil filter.
  3. Assemble the plunger valve in the large hole of the tester base and the hose in the small hole of the tester base. Connect the gauge to the end of the hose.
  4. Insert the flat side of the rubber plug, for ease of installation, in the bypass valve without depressing the bypass valve itself.
  5. Install the tester on the oil filter mounting pad.
  6. Start the engine in order to check overall pressure, sender switch, or noisy lifters. The engine should be at operating temperature before checking oil pressure. Oil pressure should be approximately 414kPa (60 psi) @ 1850 rpm using 10w30 engine oil.
  7. If adequate oil pressure is indicated, check the pressure sending switch.
  8. If a low reading is indicated, depress 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 would indicate a good oil pump and that the previous low pressure was due to worn bearings, etc. A low reading while depressing the valve would indicate a faulty oil pump.