For 1990-2009 cars

# INFO. ON REVISED CRANKSHAFT BALANCER

REVISION: 10/26/94

THIS BULLETIN IS BEING REVISED TO CLARIFY INFORMATION IN THE "CYLINDER HEAD" SECTION OF THE BULLETIN. ----------------------------------------------------------------------

#### SUBJECT: INFORMATION ON REVISED CRANKSHAFT BALANCER/CYLINDER HEAD BOLT USAGE AND TORQUE SPECIFICATIONS

#### MODELS: 1987-92 CADILLAC ALLANTE 1982-95 CADILLAC DEVILLE 1982-93 CADILLAC ELDORADO AND SEVILLE 1982-85 CADILLAC FLEETWOOD BROUGHAM 1985-93 CADILLAC SIXTY SPECIAL/FLEETWOOD WITH 4.1L, 4.5L OR 4.9L ENGINES (VINS 3, 5, 7, 8, B - RPOS LT8, LC7, LR6, LQ6, LW2, L26)

CRANKSHAFT BALANCER AND CYLINDER HEAD TORQUE SPECIFICATIONS ARE NOW REVISED. SPECIFICATIONS AND NEW SERVICE PROCEDURES ARE DEFINED BELOW.

#### CRANKSHAFT BALANCER BOLT

THE NEW CRANKSHAFT BALANCER TORQUE SPECIFICATION IS **160 N.M (118 LB. FT.)**. THIS TORQUE SPECIFICATION APPLIES TO ALL ENGINES EQUIPPED WITH A **WASHER FACE BOLT** (SEE FIGURE 1) ALONG WITH A SEPARATE WASHER.

THIS WASHER FACE BOLT REPLACES THE **PREVIOUS STANDARD HEAD BOLT** (SEE FIGURE 2) AND SEPARATE WASHER ARRANGEMENT WHICH HAS A TORQUE SPECIFICATION OF 95 N.M (70 LB. FT.).

WHENEVER SERVICING A CRANKSHAFT BALANCER HELD BY A WASHER FACE BOLT, USE THE REVISED 160 N.M (118 LB. FT.) TORQUE SPECIFICATION.

IF SERVICING A CRANKSHAFT BALANCER WITH THE STANDARD HEAD BOLT, USE THE 95 N.M (70 LB. FT.) TORQUE SPECIFICATION.

#### NOTE: EARLY 1988 4.5L AND ALL 4.1L ORIGINAL EQUIPMENT ENGINES DO NOT HAVE A CRANKSHAFT BALANCER RETAINING BOLT.

#### IMPORTANT: LONG AND SHORT-BLOCK REPLACEMENT ENGINES, INCLUDING THE TRANSVERSE 4.1L V-8 BUILT **AFTER JUNE OF 1990** ARE EQUIPPED WITH THE WASHER FACE BOLT AND SHOULD USE THE 160 N.M (118 LB. FT.) TORQUE SPECIFICATION. REPLACEMENT TRANSVERSE ENGINES BUILT BETWEEN NOVEMBER 1987 AND JUNE 1990 USE THE STANDARD HEAD BOLT AND USE THE 95 N.M (70 LB. FT.) TORQUE SPECIFICATION.

#### CYLINDER HEAD

THE CYLINDER HEAD BOLT TORQUE SEQUENCE FOR 4.1L, 4.5L AND 4.9L ENGINES IS REVISED. WHENEVER SERVICING THE CYLINDER HEADS OF THESE ENGINES, MEASURE THE THREAD LENGTH OF THE INBOARD AND OUTBOARD CYLINDER HEAD BOLTS TO DETERMINE THE PROPER TORQUE SPECIFICATION.

TO DETERMINE THREAD LENGTH, USE A MILLIMETER SCALE AND MEASURE FROM THE FIRST THREAD (CLOSEST TO THE BOLT HEAD) TO THE END OF THE BOLT. REFER TO THE CHART BELOW FOR BOLT APPLICATION AND USAGE.

#### IMPORTANT: TAPER GRIND (SEE FIGURE 5) THE END OF BOLTS WITH THREAD LENGTHS OF 39 TO 41 MM. WITHOUT TAPER GRINDING, THESE BOLTS MAY "BOTTOM OUT" IN THE ENGINE BLOCK BEFORE PROPER TORQUE IS ACHIEVED, RESULTING IN IMPROPER SEALING BETWEEN THE CYLINDER HEAD AND BLOCK.

APPROXIMATE TORQUE SEQUENCE/ THREAD LENGTH SPECIFICATION ENGINE APPLICATION ------------- ---------------- ------------------ INBOARD STUD - 50 MM SEE FIGURE 3 ANY 4.9L, 4.5L OR 4.1L OUTBOARD BOLT - 47 MM

INBOARD STUD - 41 MM SEE FIGURE 4 **ONLY** THOSE ENGINES THE OUTBOARD BOLT - 39 MM STATED STUDS/BOLTS ARE REMOVED FROM AND **AFTER TAPER GRINDING** 1 TO 1.5 MM FROM THE END OF THE BOLT (SEE FIGURE 5)

#### IMPORTANT: WHEN TAPER GRINDING A BOLT OR STUD, BE SURE TO INSTALL AN M12 X 1.75 NUT BEYOND THE GRINDING POINT. WHEN GRINDING IS COMPLETE, REMOVING THE NUT WILL CLEAN THE THREADS AT TIP OF THE BOLT AND EASE INSTALLATION.

PLEASE UPDATE SECTION 6A OF YOUR SERVICE MANUAL AS APPROPRIATE.

FIGURES: 5

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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