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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 421 (Engine Mechanical - 4.8L, 5.3L, & 6.0L (On-Vehicle)) >> Diagnostic Information and Procedures >> Oil Consumption Diagnosis

Oil Consumption Diagnosis

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Oil Consumption Diagnosis

Checks Causes
Excessive oil consumption, not due to leaks, is the use of 1 L (1 qt) or more of engine oil within 3 200 kilometers (2,000 miles).
Preliminary The causes of excessive oil consumption may include the following conditions:
  • External oil leaks

    Refer to Oil Leak Diagnosis .

  • Incorrect oil level or improper reading of the oil level indicator

    With the vehicle on a level surface, run the engine for a few minutes, allow adequate drain down time, 2-3 minutes, and check for the correct engine oil level.

  • Improper oil viscosity

    Refer to the vehicle owners manual and use the recommended SAE grade and viscosity for the prevailing temperatures.

  • Continuous high speed driving and/or severe usage
  • Crankcase ventilation system restrictions or malfunctioning components
  • Worn valve guides and/or valve stems
  • Worn or improperly installed valve stem oil seals
  • Piston rings broken, worn, or not seated properly

    Allow adequate time for the rings to seat.

    Replace worn piston rings as necessary.

  • Piston and rings improperly installed or not fitted to the cylinder bore