GM Service Manual Online
For 1990-2009 cars only

Excessive oil consumption (not due to leaks) is the use of 1.9 liters (2 quarts) of engine oil within 3 200 km (2,000 mi). However, during initial engine break-in periods 4 828-6 437 km (3,000-4,000 mi) oil consumption may exceed 1.9 liters (2 quarts) or more. The causes of excessive oil consumption include the following conditions:

    • External oil leaks. Tighten the bolts and/or replace gaskets and oil seals as necessary.
    • Incorrect oil level or improper reading of oil level indicator. With the vehicle on a level surface, allow adequate drain down time and check 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, damaged, or the seal omitted. Ream the valve 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 piston rings to seat. Replace broken or worn piston rings as necessary.
    • Piston improperly installed or miss-fitted.