Pop Noise from Underbody After Vehicle is Parked or When Stationary at Idle #98-T-36 - (Jan 6, 2003)

Pop Noise From Underbody After Vehicle is Parked or When Stationary at Idle (Replace Loose Exhaust Heat Shield Rivets)

1996-1998 Saturn Vehicles

Condition

After vehicle is parked or at idle for an extended period of time some customers may hear a pop noise from the underbody of vehicle. The noise may sound like an object hitting the bottom of vehicle and is audible inside or outside vehicle.

Cause

Some exhaust heat shield to body pop rivets may not have adequate clamp load to prevent the heat shield from slipping under the head of the rivet as it expands and contracts.

Correction

The condition can be duplicated with the vehicle on a lift. Use the Tech 2 speed control special function or the PDT IAC special test to set engine speed to 1500 RPM. This will generate enough heat in the exhaust system to allow the heat shield to fully expand. With engine running, transaxle in Park, and engine speed set to 1500 RPM, raise vehicle on a lift and a monitor the heat shield. As the shield is heated and expands, the loose rivet can be identified. The heat shield may have to be heated and cooled several times to pinpoint the rivet or rivets that are making noise. A fan can be used to cool the shield between cycles.

Replace the rivets that are loose. Refer to the "Catalytic Converter and Intermediate Pipe Heat Shields" or "Muffler Heat Shield" Procedure in the Isolators Section of the appropriate model year Engine/Fuel/Air Intake/Exhaust Service Manual.

Parts Requirement

09442468 - Rivet - Exh Heat Shield

Claim Information

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as follows:

Case Type	Description	Labor Operation Code	Time
VW	Replace rivet(s) in exhaust heat shield(s)	Z4003	0.3 hrs
Add:	To replace each additional rivet		0.1 hrs
	To R catalytic converter to access rivet(s)		0.5 hrs
	To R muffler to access rivets(s)		0.5 hrs

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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