GM Service Manual Online
For 1990-2009 cars only

The accepted rate of oil consumption, not due to leaks, is the use of more than 0.946 liter (1 qt) within 379 liters (100 gallons) of juel used. This rate only applies to vehicles under warranty, maintained in accordance with the appropriate maintenance schedule, driven at legal speeds and within design intent of the vehicle.

Oil economy should not be tested until the vehicle has accumulated at least 8000 km (5000 mi) and the oil has been changed for the first time. During initial engine break-in periods before the first oil change, oil consumption may exceed 1.9 liters (2 qts) or more per 379 liters (100 gallons) of fuel used.

Checks

Causes

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, not seated properly
        Allow adequate time for the rings to seat.
        Replace worn piston rings as necessary.
    • Piston and rings improperly installed or improperly fit to the cylinder bore
    • Turbocharger oil leaks - Inspect the turbocharger exhaust outlet and the turbocharger air inlet duct for excessive oil residue. Excessive oil may indicate a restricted oil drain pipe or worn turbocharger bushings/seals. If turbocharger wear is at fault, inspect for continuous oil flow from the turbocharger oil feed line. Restricted oil flow may indicate a blocked oil feed line, blocked oil passage in the engine block, or a spun camshaft bearing.