SMU-SECT. 6-ENG. MECH CYLINDER HEAD INSTALLATION

REVISION: 10/01/97

THIS BULLETIN IS BEING REVISED TO ADD CYLINDER HEAD INSTALLATION INFORMATION. ______________________________________________________________________

SUBJECT: SERVICE MANUAL UPDATE - SECTION 6 - ENGINE MECHANICAL - CYLINDER HEAD INSTALLATION

MODELS: 1992-1997 C, K, G, AND P TRUCKS WITH 6.5L DIESEL ENGINES (VINS P, S, Y, F--RPOS L49, L56, L57, L65, L65-CMT)

THE CYLINDER HEAD TORQUING SEQUENCE HAS BEEN REVISED. THE NEW PROCEDURE INCORPORATES TORQUE ANGLE IN THE FINAL TIGHTENING SEQUENCE, SIMILAR TO THE CURRENT CRANKSHAFT AND BEARINGS INSTALLATION PROCEDURE. FOR ALL MODEL YEARS OF THE 6.5L ENGINE, USE THE INFORMATION PROVIDED IN THIS BULLETIN. THIS INFORMATION IS ALSO AVAILABLE IN THE 1998 SERVICE MANUAL.

CYLINDER HEAD INSTALLATION

IMPORTANT

MAKE SURE THAT THE BLOCK GASKET SURFACES ARE CLEAN.

THE HEAD GASKET MATERIAL IS SOFT. HANDLE THE GASKET WITH CARE. MAKE SURE THE GASKET SURFACE IS NOT CREASED OR DENTED.

DO NOT USE A SEALER ON THE HEAD GASKET. THE HEAD GASKET IS MADE WITH SEALANT ON THE GASKET SURFACE. ADDITIONAL SEALER MAY CAUSE LEAKAGE OR MALFUNCTION. IN ADDITION, SOME SEALERS MAY ATTACK THE INITIAL SEALANT ON THE GASKET.

{INSERT FIGURE 1 (59803) HERE}

1. INSTALL THE CYLINDER HEAD GASKETS TO THE BLOCK, OVER THE CYLINDER HEAD DOWEL PINS.

2. INSTALL THE CYLINDER HEADS TO THE BLOCK, OVER THE CYLINDER HEAD GASKETS AND THE CYLINDER HEAD DOWEL PINS.

{INSERT FIGURE 2 (60278) HERE}

3. APPLY THREAD SEALANT GM P/N 12345382 OR EQUIVALENT, TO THE BOLT THREADS AND UNDER THE BOLT HEADS.

FASTENER NOTICE

NOTICE: USE THE CORRECT FASTENER IN THE CORRECT LOCATION. REPLACEMENT FASTENERS MUST BE THE CORRECT PART NUMBER FOR THAT APPLICATION. FASTENERS REQUIRING REPLACEMENT OR FASTENERS REQUIRING THE USE OF THREAD LOCKING COMPOUND OR SEALANT ARE IDENTIFIED IN THE SERVICE PROCEDURE. DO NOT USE PAINTS, LUBRICANTS, OR CORROSION INHIBITORS ON FASTENERS OR FASTENER JOINT SURFACES UNLESS SPECIFIED. THESE COATINGS AFFECT FASTENER TORQUE AND JOINT CLAMPING FORCE AND MAY DAMAGE THE FASTENER. USE THE CORRECT TIGHTENING SEQUENCE AND SPECIFICATIONS WHEN INSTALLING FASTENERS IN ORDER TO AVOID DAMAGE TO PARTS AND SYSTEMS.

4. INSTALL THE CYLINDER HEAD BOLTS USING THE INSTALLATION AND TIGHTENING SEQUENCE SHOWN IN FIGURE 2.

TIGHTEN

IN SEQUENCE (FIGURE 2), TIGHTEN ALL OF THE CYLINDER HEAD BOLTS TO 25 N.M (20 LB FT).

IN SEQUENCE (FIGURE 2), TIGHTEN ALL OF THE CYLINDER HEAD BOLTS TO 75 N.M (55 LB FT).

IN SEQUENCE (FIGURE 2), RETIGHTEN ALL OF THE CYLINDER HEAD BOLTS TO 75 N.M (55 LB FT).

IN SEQUENCE (FIGURE 2), TIGHTEN ALL OF THE CYLINDER HEAD BOLTS AN ADDITIONAL 90 DEGREES - 100 DEGREES (1/4 PLUS TURN).

FIGURES: 2 ATTACHMENTS: 0

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.

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