PCV SYS. FREEZE-UP (PCV VALVE UPGRADE FOR COLD WEATHER). Chevrolet Blazer

THIS BULLETIN IS BEING REVISED TO INFORM "GM OF CANADA" AND "NAES" DEALERS THAT THEY ARE NOT AUTHORIZED TO UTILIZE THIS SERVICE BULLETIN

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"GM OF CANADA" AND "NAES" DEALERS ARE NOT AUTHORIZED TO UTILIZE THIS SERVICE BULLETIN.

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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 M/L VANS 1992-94 OLDSMOBILE BRAVADA WITH 4.3L (L35) ENGINES (DESIGNATED COLD STATES ONLY) ******************************************************************** SOME OWNERS MAY EXPERIENCE A CONDITION IF OPERATED BELOW -30 DEGREES CELSIUS (-22 DEGREES FAHRENHEIT) 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 LETTERS RECOMMENDING SERVICE UPGRADE OF THE PCV VALVE IF THEY ANTICIPATE OPERATING IN TEMPERATURES BELOW -30 DEGREES CELSIUS (-22 DEGREES FAHRENHEIT). 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 FOLLOWING VIN BREAKPOINTS:

YEAR MAKE MODEL PLANT FROM THROUGH ---- ---- ----- ----- ---- ------- 1992 CHEVROLET M/L/S/T ALL S.O.P. E.O.P. 1993 CHEVROLET M/L/S/T ALL S.O.P. E.O.P. 1994 CHEVROLET M/L BALTIMORE S.O.P. RB108397 1994 CHEVROLET S/T PONTIAC WEST S.O.P. R0101984 MORAINE S.O.P. R2107894 SHREVEPORT S.O.P. R8108651 LINDEN S.O.P. RK103093

1992 GMC M/L/S/T ALL S.O.P. E.O.P. 1993 GMC M/L/S/T ALL S.O.P. E.O.P. 1994 GMC M/L BALTIMORE S.O.P. RB503075 1994 GMC S/T PONTIAC WEST S.O.P. R0500571 MORAINE S.O.P. R2502543 SHREVEPORT S.O.P. R8501909 LINDEN S.O.P. RK501072

1992 OLDSMOBILE T ALL S.O.P. E.O.P. 1993 OLDSMOBILE T ALL S.O.P. E.O.P. 1994 OLDSMOBILE T MORAINE S.O.P. R2700299

NOTE: S.O.P. IS "START OF PRODUCTION"; E.O.P. IS "END OF PRODUCTION."

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:

QUANTITY/ PART NUMBER DESCRIPTION VEHICLE ----------- ----------- --------- 6487532 VALVE - PCV (1992/93) 1 6487779 VALVE - PCV (1994) 1

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 NUMBER: J6000 USE TIME PUBLISHED IN LABOR TIME GUIDE.

FIGURES: 0

*** LETTER TO OWNERS ***

DEAR _____________ OWNER:

THIS LETTER IS TO INFORM YOU OF A REVISED POSITIVE CRANKCASE VENTILATION VALVE AVAILABLE FOR YOUR VEHICLE AND RECOMMENDED BY _____________________ IF YOU OPERATE YOUR VEHICLE IN VERY COLD TEMPERATURES (-30 DEGREES CELSIUS OR -22 DEGREES FAHRENHEIT).

GENERAL MOTORS HAS DETERMINED THAT CERTAIN 1992-94 ASTRO VANS, S10 AND T10 BLAZER AND PICKUP TRUCKS, WHEN EQUIPPED WITH A 4.3L V6 (RPO L35) ENGINE, MAY EXPERIENCE ICE BUILD UP IN THE PCV SYSTEM IF OPERATED AT TEMPERATURES BELOW -22 DEGREES FARENHEIT OR -30 DEGREES CELSIUS. OPERATION OF THE VEHICLE WITH ICE IN THE PCV HOSES WILL PRESSURIZE THE ENGINE CRANKCASE AND RESULT IN ENGINE OIL LEAKS. CONTINUED VEHICLE OPERATION MAY RESULT IN MAJOR ENGINE FAILURE DUE TO INSUFFICIENT LUBRICATION.

IF YOU ANTICIPATE OPERATING YOUR VEHICLE IN TEMPERATURES BELOW -30 DEGREES CELSIUS (-22 DEGREES FAHRENHEIT), ___________________ RECOMMENDS THE USE OF A HIGHER FLOW RATE POSITIVE CRANKCASE VENTILATION (PCV) VALVE. YOUR ___________________ DEALER HAS A TECHNICAL BULLETIN ON THIS SITUATION AND WILL REPLACE YOUR PCV VALVE AT NO CHARGE TO YOU UNDER THE EMISSIONS WARRANTY. IF YOU ANTICIPATE NEEDING THIS EXTRA COLD WEATHER PROTECTION, PLEASE CONTACT YOUR DEALER TO ARRANGE A SERVICE DATE AND ASSURE PARTS ARE AVAILABLE.

WE ARE SORRY FOR ANY INCONVENIENCE THIS MAY CAUSE YOU BUT WE ARE INTERESTED IN YOUR CONTINUED SATISFACTION WITH YOUR ____________ VEHICLE.

*** END OF LETTER ***

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.