INFO. ON 1997 TRUCKS WITH 6.5L DIESEL ENGINE. GMC Truck Yukon

SUBJECT: INFORMATION ON 1997 TRUCKS WITH 6.5L DIESEL ENGINE INTERIM PRODUCT UPDATES

MODELS: 1997 CHEVROLET AND GMC C/K, G, AND P TRUCKS WITH 6.5L DIESEL ENGINE (VINS F, S, Y - RPOS L65, L56, L57) BUILT AFTER JANUARY 13, 1997

VIN BREAKPOINTS: PONTIAC EAST - CHEV (L56) 1GCEK19S2VE194731 - CHEV (L65) 1GCGK29F8VE193553 - GMC (L56) 1GTFC29S3VE536047 - GMC (L65) 1GTHC39F6VE532480

FLINT - CHEV 1GCHC33F7BF022349 - GMC 1GTHC39F6BF022642

FORT WAYNE - CHEV 1GCHK34F5VZ175523 - GMC 1GTGK24F8VZ524244

JANESVILLE (1) - CHEV 1GBKC34F7VJ105768 - GMC 1GKJK16F2VJ725146

JANESVILLE (2) - CHEV XXXXXXXXXXX356858 - GMC XXXXXXXXXXX510527

SILAO - CHEV (L56) 3GNEK18S6VG133867 - GMC (L65) 3GKGK26F5VG511436

THE FOLLOWING PRODUCT UPDATES HAVE BEEN IMPLEMENTED ON THE 6.5L DIESEL ENGINE FOR MID-PRODUCTION IN THE 1997 MODEL YEAR. THIS INFORMATION IS LISTED AS A BRIEF OVERVIEW. THE UPDATES ARE AN ENHANCEMENT TO THE 1997 6.5L DIESEL ENGINE.

#1 COMPRESSION (FIRE) RING (ALL APPLICATIONS) THE MATERIAL OF THE FIRE RING HAS BEEN CHANGED TO MOLY-CARBIDE TO INCREASE DURABILITY.

PCM CALIBRATION UPDATE (L56 C/K ONLY) THE VEHICLE PCM CALIBRATION WAS UPDATED TO ALLOW ENHANCED EGR DIAGNOSTICS.

PCM CALIBRATION UPDATE (L65 C/K ONLY) THE VEHICLE PCM CALIBRATION WAS UPDATED TO ALLOW GREATER HORSEPOWER (195) AND GREATER TORQUE: A/T @ 430, AND M/T @ 420.

EMISSION LABELS (L65 C/K ONLY) THE LABELS HAVE BEEN UPDATED TO REFLECT THE INCREASE IN HORSEPOWER (195) AND TORQUE (420 OR 430).

CLUTCH AND CLUTCH BOLT LOCK WASHER (ALL M/T APPLICATIONS) THE CLUTCH WAS UPDATED FOR THE INCREASE IN HORSEPOWER AND TORQUE. A LOCK WASHER HAS BEEN ADDED TO THE CLUTCH RETAINING BOLTS.

OIL COOLER LINE CONNECTORS (C/K AND P) THE FITTINGS HAVE BEEN CHANGED FROM 1/2"ID TO 5/8"ID TO CONNECT TO THE LARGER OIL COOLER LINES. G VAN HAS THESE PARTS FROM MY97 SOP.

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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.