Higher Than Expected Engine Oil Consumption (Replace PCV Valve)

This bulletin is being revised to clarify the parts information. Please discard Corporate Bulletin Number  01-06-01-029A (Section 06 -- Engine/Propulsion System).

Some customers may comment on higher than expected engine oil consumption. They may further comment on consumption in the range of 3,200 km (2,000 mi) or less per quart (0.946 liter) of oil under normal driving conditions.

The condition may be due to the positive crankcase ventilation (PCV) valve flow rate under certain engine operating conditions.

1. Verify that the oil consumption is not the result of an oil leak or other engine concern.
2. The dealer should perform an oil consumption test. The vehicle should have accumulated over 6,450 km (4,000 mi) before establishing the oil consumption rate. Reference Corporate Bulletin Number 01-06-01-011, Information on Engine Oil Consumption Guideline, for details.
3. Remove the PCV valve and inspect the hose going to the intake manifold for signs of excessive oil being present.
4. If excessive oil is present in the PCV hose, replace the PCV valve (Type 948C) (2) with a new-style fixed orifice PCV valve, GM P/N 12572717(1). See the illustration below.

PCV Valve Identification

Important: The new style fixed orifice PCV valve contains no moving parts, and does not rattle when shaken.

If the vehicle has an orifice style PCV valve, investigate other causes for high oil consumption.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: