Fuel Tank/Underbody - Creak/Groan Noise

91pontiac15

Bulletin Number: 91-6-28A
Reference Number: 136304
Publish Date: 10/91


Subject: FUEL TANK/UNDERBODY NOISE (SERVICE PROCEDURE FOR INSTALLING FUEL TANK STRAPS AND SPACERS)

Models
Affected: 1989-91 GRAND PRIX MODELS


This bulletin cancels and supersedes Service Bulletin 91-6-28 issued 3/91. Also additional information and part numbers are provided to address another fuel tank related noise condition.

Condition: Some 1989-91 Grand Prix models may exhibit a creak/groan or in severe instances a clunk/thud type noise coming from the rear of the vehicle. This noise is most apparent when a vehicle twisting motion is generated, such as that which would be experienced when turning up a steep incline/driveway.

Cause: These noise conditions may be caused by the fuel tank flange contacting the underbody crossbar located forward of the fuel tank or movement between the tank and retaining straps.

Correction: On 1989-91 vehicles assembled prior to VIN breakpoints indicated below, install new fuel tank straps, P/N 10199250 (2 required), and strap spacers, P/N 10192675 (2 required).

On 1991 vehicles assembled after VIN breakpoints it will only require installation of tank straps, P/N 10199250 (2 required) and the transfer of existing strap spacers.

The VIN breakpoint is MF235111.

Service Procedure:

1. Raise vehicle on hoist.

2. Remove exhaust intermediate pipe heat shield.





3. Support fuel tank assembly.


4. Remove RH fuel tank strap attaching bolts/screws, remove spacer from strap if present, discard strap.

5. Install strap spacer, P/N 10192675, on new strap, P/N 10199250, as shown on Illustration.

Parts are currently available from GMSPO.

NOTICE: DO NOT BEND FUEL TANK STRAPS, AS THIS MAY DAMAGE STRAPS.

6. Position strap and loosely install attaching bolts/screws.

7. Repeat steps 4 thru 6 for LH strap.

8. Insuring a minimum of 4 mm of clearance is maintained between fuel tank flange and underbody bar, torque attaching bolts/screws to 40-54 N-m (29-39 lbs.ft.).

9. Install exhaust heat shield and torque bolts/screws to 2 N-m (1.5 lbs.ft.).

10. Remove support from under fuel tank and lower vehicle.

Labor Operation Number : T1677

Labor Time : .4 Hours