1996 GLOW PLUG OPERATION, DIAGNOSIS & USAGE, SERVICING. Chevrolet Chevy P RV/Van/Commercial Chassis 1996

REVISION: 11/13/95

THIS BULLETIN IS BEING REVISED TO INFORM GM OF CANADA DEALERS THAT A DIFFERENT PART NUMBER IS APPLICABLE FOR CANADA. GM OF CANADA DEALERS- PLEASE DISCARD CORPORATE BULLETIN NUMBER 57-64-06 (SECTION 6 - ENGINE). **********************************************************************

SUBJECT: INFORMATION ON 1996 GLOW PLUG OPERATION, DIAGNOSIS AND USAGE, SERVICING 1992-96 GLOW PLUGS

MODELS: 1992-96 CHEVROLET AND GMC C/K, G, P MODELS WITH 6.5L ENGINE (VINS F,P,S,Y - RPOS L65,L49,L56,L57)

THE 1996 TRUCKS WITH 6.5L DIESEL ENGINE USE AN 11G GLOW PLUG, SERVICE PART NUMBER 25168651 (CANADIAN DEALERS USE SERVICE PART NUMBER 25171171). THIS GLOW PLUG SERVICES ALL 6.5L ENGINES. THE 11G GLOW PLUG IS A POSITIVE TEMPERATURE COEFFICIENT PLUG THAT LIMITS THE CURRENT TO THE HEATING ELEMENT AS THE PLUG HEATS UP.

1996 GLOW PLUG SYSTEM OPERATION THE PRE-GLOW TIMES REMAIN APPROXIMATELY THE SAME AS PREVIOUS MODEL YEARS. FOR 1996 THE POST-GLOW CYCLING IS ACTIVATED SOONER (WITHIN TWO SECONDS), AFTER THE PRE-GLOW CYCLE IS COMPLETED WHETHER CRANKING ENGINE IMMEDIATELY OR IF CUSTOMER WAITS BEFORE CRANKING. THIS CHANGE WILL MAINTAIN ENGINE COMBUSTION TEMPERATURES FOR BETTER STARTING OF THE ENGINE. A TECHNICIAN OR CUSTOMER WILL NOTICE THE GLOW PLUG "WAIT" LIGHT ON MORE OFTEN DURING THE INITIAL START AND/OR INITIAL RUNNING OF THE ENGINE AS COMPARED TO 1994-95 MODEL YEARS. THE AMOUNT OF POST- GLOWS AND DURATION OF GLOW PLUG CYCLES IS DETERMINED BY ENGINE TEMPERATURES, BAROMETER, ALTITUDE AND BATTERY VOLTAGE.

DIAGNOSTIC INFORMATION 1. IGNITION "OFF". 2. DISCONNECT ALL GLOW PLUGS. 3. WITH A TEST LIGHT CONNECTED TO B PLUS (BATTERY POSITIVE TERMINAL), PROBE THE SPADE TERMINAL ON EACH GLOW PLUG. 4. DO ALL GLOW PLUGS TURN TEST LIGHT "ON"? IF YES, GLOW PLUGS ARE OKAY. IF NO, REPLACE GLOW PLUGS THAT DO NOT TURN "ON" THE TEST LIGHT.

IF AN AMP METER IS USED, IT MUST HAVE A "PEAK/HOLD" FEATURE CONNECTED PRIOR TO TURNING IGNITION ON FOR CORRECT READINGS. IF NOT, UNNECESSARY REPLACEMENT OF A GLOW PLUG COULD OCCUR. THE AMP METER WILL INDICATE DECREASING CURRENT WITHIN THE "KEY ON" TIME PERIOD WHILE THE "WAIT" LIGHT IS ON. A SUBSEQUENT OR SECOND ATTEMPT WITH "KEY ON" CYCLE WILL RESULT IN EVEN LOWER READINGS ON THE AMP METER. PRIOR TO REPLACING ANY 11G GLOW PLUG CHECKED WITH AN AMP METER THE TEST LIGHT METHOD SHOULD BE USED FOR VERIFICATION TO AVOID UNNECESSARY REPLACEMENT OF A GLOW PLUG.

SERVICING ALL TRUCKS WITH A 6.5L ENGINE 1. DO NOT INSTALL A 9G GLOW PLUG INTO A 1996 TRUCK WITH A 6.5L DIESEL ENGINE (9G PART NUMBER 25163212 WAS RELEASED IN PRIOR MODEL YEARS).

2. USE 11G GLOW PLUGS FOR ALL 6.5L DIESEL ENGINES (REGARDLESS OF MODEL YEARS). THE 11G GLOW PLUG CAN BE INTERMIXED ON 1995 AND PRIOR MODEL YEARS THAT HAVE EXISTING 9G GLOW PLUGS.

3. THE 9G GLOW PLUG IS ONLY APPLICABLE TO THE 6.2L (LH6, LL4) DIESEL ENGINE.

PARTS INFORMATION

PART NUMBER DESCRIPTION 25168651 GLOW PLUG (11G)-NON-CANADIAN DEALERS 25171171 GLOW PLUG (11G)-CANADIAN DEALERS ONLY

WARRANTY INFORMATION FOR VEHICLES UNDER WARRANTY, USE:

LABOR OPERATION LABOR TIME J4760 (RIGHT) USE PUBLISHED LABOR OPERATION TIME. J4761 (LEFT) USE PUBLISHED LABOR OPERATION TIME. J4767 (BOTH) USE PUBLISHED LABOR OPERATION TIME.

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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.