Rattle or Clunk Noise from Rear of Vehicle at Normal Operating Temperature #98-T-41 - (Dec 1, 2003)

1998 Saturn vehicles built after and including VIN WZ217016

1999 Saturn vehicle built up to and including:

VIN XZ119715 with RPOs LL0 and NC1 (DOHC CA Emissions)

VIN XZ129456 with RPOs LL0 and NF2 (DOHC Federal Emissions)

VIN XZ129407 with RPOs L24 and NF2 (DOHC Federal Emissions)

VIN XZ134512 with RPOs L24 and NB7 (SOHC CA Emissions)

Condition

Muffler assembly may contact the muffler ramp that is welded to the spaceframe.

Cause

The clearance between muffler and muffler ramp may be inadequate. As the exhaust system heats up it expands rearward. This expansion reduces the clearance between the muffler and muffler ramp. If the clearance becomes too small the muffler may contact the muffler ramp. This may occur under the following conditions with the vehicle at normal operating temperature:

• Driving over rough surfaces
• Shifting automatic transaxle, if equipped, drive to reverse
• Launching vehicle in reverse with manual transaxle, if equipped
• Starting or shutting off the engine

Correction

Drive the vehicle under the above condition with vehicle at operating temperature to verify that the rattle or clunk noise is caused by the muffler contacting the muffler ramp. A witness mark may be present on the muffler and muffler ramp at the point of contact. If the rattle or clunk noise is not head coming from the muffler contacting the muffler ramp, road test vehicle to locate the source of the noise and follow the diagnostic procedures in the appropriate model year service manual. If the rattle or cluck noise is determined to be from muffler to ramp contact, adequate clearance should be obtained by installing a service muffler assembly. Follow the modified muffler replacement procedure in the bulletin.

Procedure

Muffler Removal

Caution

Make sure vehicle is properly supported and squarely positioned prior to lifting. To help avoid personal injury when a vehicle is on a hoist, provide additional support for the vehicle on the opposite end from which components are being removed.

1. Raised vehicle and support squarely on lift.
2. Locate center of the approximately 100 mm (4.0 in) long straight section and mark the pipe. Measure 13-19 mm (1/2-3/4 in) forward of the center and mark for cutting.





Notice

Always use a chain cutter to cut stainless steel exhaust system pipes.

3. Using chain cutter SA1968NE (or equivalent), cut intermediate pipe in front of the rear suspension.
4. Remove muffler strap fastener and muffler.

Muffler Installation

1. Loosely install muffler clamp on service replacement muffler inlet.
2. Load replacement muffler to vehicle, sliding muffler inlet pipe over cut section of intermediate pipe.
3. Hold muffler in location to muffler strap and tighten clamp. Locate muffler strap between stamped channel in the muffler.





Important

Make sure that after installing the replacement exhaust sections that the system has not shifted rearward allowing contact between the hanger bracket screw and the hanger block. If contact exists, noise will result; so, loosen the muffler strap, shift forward on muffler to eliminate contact, and retighten.

4. Position and tighten the service muffler to ensure that there is 19 mm (3/4 in) of clearance between the muffler and muffler ramp.
Tighten

Tighten 22N·m (16 lb ft).






Notice

Locate muffler clamp 25 mm (1.0 in) from end of muffler inlet pipe and position clamp with U-bolt facing away from fuel tank.

5. Make sure that muffler clamp is properly positioned and aligned. Tighten clamp.
Tighten

Tighten the muffler clamp to 41 N·m (30 lb ft).






Important

If muffler movement cannot be obtained or muffler isolator block is damaged, the exhaust system will have to be carefully lowered for adjustment or replacement of the muffler isolator block. Washers may have to be installed between muffler block bolt and frame rail to align the hanger parallel with muffler.

6. Check entire exhaust system for proper alignment, clearance to heat shields, and leaks. Muffler body band clamp must be free to move in hanger or vibrations will be transmitted from exhaust system into body. Muffler can be moved both vertically and horizontally in the isolator block. Muffler should move 1/16 in vertically and 1/8 in horizontally minimum in the isolator block.

Parts Requirements

Claim Information

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System using the appropriate Electronic Labor Time Guide and Labor Operation Code L2584, (Muffler Replace).

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer".  They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.

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