GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 21867 Pressure Gage
    • J-21867-16 Oil Pressure Adapter
    • J 42907 Oil Pressure Tester

    Object Number: 1593649  Size: SH

    Important: This test is performed to verify the operation of the oil pressure relief valve. Refer to Lubrication Description.

  1. Remove the oil filter and install the J 42907  (1).
  2. Install the J 21867  (2), or equivalent to the J 42907  (1).

  3. Object Number: 1593653  Size: SH
  4. Remove the oil pressure sensor and install the J-21867-16 .

  5. Object Number: 1593656  Size: SH
  6. Install the J 21867  (1), or equivalent to the J-21867-16 .
  7. Run the engine and measure the engine oil pressure while observing both gages.
  8. Operate the throttle, as required, to increase and decrease the engine oil pressure.

    • With the engine running and the lower pressure gage (2) measuring below 379 kPa (55 psi), both gages should display the same pressure reading. If the readings are not the same and the lower gage (2) has a higher reading, the oil pressure relief valve is stuck in the open position.
    • With the engine running and the lower pressure gage (2) measuring above 379 kPa (55 psi), the upper gage (1) should display no greater than 379-517 kPa (55-75 psi). If the reading on the upper gage (1) is greater than 517 kPa (75 psi), the oil pressure relief valve is stuck in the closed position.
  9. Repair, as required.