KNOCKING AND/OR RATTLE NOISE FROM TIMING CHAIN/WATER PUMP

SUBJECT: KNOCKING AND/OR RATTLE NOISE FROM TIMING CHAIN HOUSING AND WATER PUMP AREA (INSTALL CHAIN NOISE KIT

(Revised to Indicate a New Part Number for the Timing Chain Noise Kit)

VEHICLES AFFECTED: 1987-88 'N' W/2.3L

CONDITION:

--------- Some 1987-1988 Cutlass Calais models equipped with a 2.3L (VIN Code D) engine may exhibit a light knocking and/or rattle noise from the timing chain housing and water pump area. This noise is usually most noticeable at or slightly above idle speed with engine at operating temperature.

CAUSE:

----- This noise may be the result of low timing chain tension. This condition does not affect engine performance or reliability.

CORRECTION:

---------- A service kit has been developed to increase timing chain tension and thereby reduce the noise.

PARTS INFORMATION:

Timing chain noise kit, part number #12337434 includes the following:

KIT INCLUDES:

-Timing Chain

-Timing Chain Tensioner Shoe

-Timing Chain Tensioner Shoe Stud

-Timing Chain Tensioner

-Timing Chain Tensioner Helper Spring

-Helper Spring Retainer Sleeve

-Timing Chain Housing Cover Gaskets

Note: Until further notice, when ordering a chain noise kit, it will also be necessary to order a chain housing cover gasket kit, part number #22535455. As soon as chain noise kits are packaged to include cover gaskets, a revised bulletin listing a new kit part number will be issued.

SERVICE PROCEDURE: Refer to Figure 1, 2 & 3 -------------------------------------------

1. Follow service manual procedure for removal of timing chain, timing chain tensioner, timing chain tensioner shoe and tensioner shoe stud.

2. Following service manual procedures, install new timing chain.

3. Install new timing chain tensioner shoe stud. Torque to 26 Nm (19 ft. lbs.).

4. Install new timing chain tensioner to chain housing. Torque bolts to 14 Nm (10 ft. lbs.).

5. Install new timing chain tensioner shoe to shoe stud.

Important: New shoe has an integral lock to retain shoe to new stud.

6. Install tensioner helper spring on post of timing chain tensioner.

7. Push plastic retainer sleeve on to helper spring post on tensioner to retain helper spring.

8. Remove anti-release from tensioner and squeeze plunger assembly into tensioner body to unload the plunger.

9. Inspect tensioner shoe helper spring for correct installed position.

10. Follow service manual procedures to verify correct crankshaft and camshaft timing. Complete installation of all other previously removed components. Use new chain housing cover gaskets supplied with kit.

SERVICE NOTES:

Torque Specifications:

- Crankshaft to crankshaft bolt 100 Nm (74 ft. lbs.) Important: After torquing crankshaft bolt rotate bolt 90 degrees.

Notice: Do not use the torque angle meter for this procedure or the meter will be damaged.

- Front cover to timing chain 12 Nm (106 in. lbs.) housing fasteners

Normally, camshaft sprocket removal is not required to remove the timing chain. (Refer to service manual procedure for timing chain removal). If however, a camshaft sprocket is removed, follow the torque procedure listed below when reinstalling the camshaft sprocket to camshaft.

- Camshaft sprocket to camshaft 50 Nm (37 ft. lbs.)

IMPORTANT: Whenever a camshaft sprocket is removed from the camshaft, the original thread adhesive on the camshaft sprocket cam bolt must be removed. Wire brush the threads of the bolt and clean the threads in the camshaft using a M10 x 1.25 thread tap. Apply thread locking compound part number 12345493, Loctite(R) 272, or equivalent to the camshaft sprocket cam bolt.

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.