GM Service Manual Online
For 1990-2009 cars only

Excessive oil consumption, not due to leaks, is the use of greater than 0.95 liter (1 quart) of engine oil within 379 liters (100 gallons) of fuel used. However, during initial engine break-in periods 5 000-6 500 kilometers (3,000-4,000 miles) oil consumption may exceed 1.9 liters (2 quarts) or greater per 379 liters (100 gallons) of fuel used. The causes of excessive oil consumption include the following conditions:

    • External oil leaks
        Tighten bolts and/or replace gaskets and oil seals, as necessary.
    • Incorrect oil level or improper reading of the oil level indicator
        With the vehicle on a level surface, allow adequate drain down time and measure for the correct oil level.
    • Improper oil viscosity
        Use recommended SAE viscosity for the prevailing temperatures.
    • Continuous high speed driving and/or severe usage
    • Crankcase ventilation system restrictions or malfunctioning components
    • Valve guides and/or valve stem oil seals worn, or the seal omitted
        Ream the guides and install oversize service valves and/or new valve stem oil seals.
    • Piston rings broken, improperly installed, worn, or not seated properly
        Allow adequate time for the rings to seat and replace broken or worn rings, as necessary.
    • Piston improperly installed or piston size is incorrectly selected