Envoy 4WD V8-5.3L VIN M (2005)
Engine Oil Pressure: Testing and Inspection
Oil Pressure Diagnosis
Oil Pressure Diagnosis and Testing
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Tools Required
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J 21867 Pressure Gage
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J 42907 Oil Pressure Tester
1. With the vehicle on a level surface, run the vehicle for a few minutes, allow adequate drain down time, 2 - 3 minutes, and measure the oil level.
2. If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
3. Run the engine briefly, 10 - 15 seconds, and verify low or no oil pressure on the vehicle gage or light.
4. Listen for a noisy valve train or a knocking noise.
5. Inspect for the following conditions:
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Oil diluted by water or glycol anti freeze
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Foamy oil, which may be caused by a cut or damaged oil pump screen O-ring seal
6. Remove the oil filter and install the J 42907.
7. Install J 21867 or equivalent to the J 42907.
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to Specifications.
10. If the engine oil pressure is below specifications, inspect the engine for one or more of the following conditions:
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Oil pump worn or dirty
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Oil pump-to-engine block bolts loose
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Oil pump screen loose, plugged, or damaged
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Oil pump screen O-ring seal missing or damaged
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Oil filter tube loose or a leaking or damaged gasket
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Malfunctioning oil pump pressure relief valve
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Excessive bearing clearance
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Cracked, porous, or restricted oil galleries
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Oil gallery plugs missing or incorrectly installed.
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Improper operation of the Displacement on Demand (DoD) oil pressure relief valve
