GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Worn valves, valve guides and/or valve stem oil seals

    • Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection in Engine Controls - 5.7L.
    • Repair or replace as required.

Worn piston rings

Oil consumption may or may not cause the engine to misfire.

    • Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection in Engine Controls - 5.7L.
    • Inspect the cylinders for a loss of compression. Refer to Engine Compression Test .
    • Perform cylinder leak down and compression testing to determine the cause. Refer to Cylinder Leakage Test .
    • Repair or replace as required.