GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J-21867-16 Oil Pressure Adapter
    • J 21867 Pressure Gage
    • J 42907 Oil Pressure Testing Tool

    Object Number: 1602748  Size: SH

    Important: This test is performed to verify the operation of the oil pressure relief valve. Refer to Displacement on Demand (DoD) System Description and Lubrication Description .

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

  3. Object Number: 1411865  Size: SH
  4. Remove the oil pressure sensor and install the J-21867-16 .

  5. Object Number: 1602751  Size: SH
  6. Install 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 448 kPa (65 psi), both gages should display the same pressure reading. If the readings are not the same and the lower pressure gage (2) has a higher reading, the oil pressure relief valve is stuck in the open position or the valve lifter oil manifold filter is plugged.
    • With the engine running and the lower pressure gage (2) measuring above 448 kPa (65 psi), the upper gage (1) should display no greater than 448 kPa (65 psi). If the reading on the upper pressure gage (1) is greater than 448 kPa (65 psi), the oil pressure relief valve is stuck in the closed position.
  9. Repair as required.