Campaign - Freeze-Up of PCV System In Cold Weather Areas

Group Ref.: Engine Fuel & Emission
Bulletin No.: 376518
Date: February, 1994

SUBJECT:
FREEZE-UP OF PCV SYSTEM HOSES IN DESIGNATED COLD STATES (PCV VALVE UPGRADE FOR COLD WEATHER PROTECTION)

MODELS:
1992-94 CHEVROLET AND GMC S/T TRUCKS AND WL VANS
1992-94 OLDSMOBILE BRAVADA
WITH 4.3L (L35) ENGINES (DESIGNATED COLD STATES ONLY)

Some vehicles may experience a condition if operated below -30~C (-22~F) in which the Positive Crankcase Ventilation (PCV) system hoses freeze up. This condition may cause engine oil leaks through the dipstick tube and/or rear main seal. Engine failure may result if the vehicle is driven with this condition.

Owners with registration in Alaska only are being notified to have their dealers replace the PCV valve with a higher flow calibrated valve as part of a product campaign (reference Product Emissions Campaign: Chevrolet-94C10, Oldsmobile-94-E-01, GMC Truck-94-E-06). Additionally, owners in specified cold weather states are going to receive

informational lefters recommending service upgrade of the PCV valve if they anticipate operating in temperatures below -30~C (-22~F). Owners in those states requesting the upgrade should receive new PCV valves under emissions warranty.

VEHICLES INVOLVED:





Involved are certain 1992-94 M/L and S/T series vehicles equipped with 4.3L (L35) engine (VIN W), registered in Colorado, Idaho, Iowa, Maine, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New York, North Dakota, South Dakota, Vermont, Wisconsin, and Wyoming, and built within the VIN breakpoints (see illustration).

OWNER NOTIFICATION:
Owners will be notified of available service upgrade on their vehicles (not a recall) (see copy of owner information letter included in this bulletin).

DEALER RESPONSIBILITY:
Dealers are to service all vehicles subject to this cold weather upgrade at no charge to owners under emissions warranty coverage.





PARTS INFORMATION:

Parts are currently available from GMSPO.

SERVICE PROCEDURE:

1. Raise engine compartment hood (on S/T trucks); remove engine cover (on M/L vans).

2. Remove PCV valve from the valve cover.

3. Remove the PCV valve from the ventilation hose.

4. Install new PCV valve to the ventilation hose.

5. Install new PCV valve to valve cover.

6. Lower engine compartment hood (on S/T trucks); install engine cover (on M/L vans).

WARRANTY INFORMATION:
For vehicles repaired under warranty, use:

Labor Operation: J6000

Labor Time: Use time published in Labor Time Guide.





LETTER TO OWNERS