Envoy 2WD V8-5.3L VIN M (2005)
4. Install the J 21867 (1), or equivalent, to the J-21867-16 (2).
5. Run the engine and measure the engine oil pressure while observing both gages. Operate the throttle as required to increase and decrease the
engine oil pressure.
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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 DoD oil pressure relief valve is stuck in the open
position or the valve lifter oil manifold filter is plugged.
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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 DoD oil pressure relief valve is stuck in
the closed position.
6. Repair as required.
