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Oil Pressure Diagnosis and Testing

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required 

  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:
    • Oil diluted by water or glycol anti freeze
    • Foamy oil
  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 Engine Mechanical Specifications (LR4 VIN V)  or Engine Mechanical Specifications (LM7 VIN T)  or Engine Mechanical Specifications (L59 VIN Z)  or Engine Mechanical Specifications (LQ4 VIN U)  or Engine Mechanical Specifications (LQ9 VIN N) .
  10. If the engine oil pressure is below specifications, inspect the engine for one or more of the following:
  11. If the oil pressure reading on the J 21867  or equivalent is within specifications, inspect for the following:
    • Plugged or incorrect oil filter and/or malfunctioning oil bypass valve
    • Malfunctioning oil pressure gage or sensor Repair as necessary.
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