EXHAUST HEAT SHIELD RATTLE (REPOSITION HEAT SHIELD)

Subject: EXHAUST HEAT SHIELD RATTLE

Model and Year: 1987-91 S1/T1 TRUCKS WITH 4.3L ENGINE

Some 1987-1991 S/T vehicles with a 4.3L engine may experience exhaust manifold heat shield rattle. This condition can occur if the heat shield is improperly installed.

To correct this condition, it is necessary to reposition the heat shield and bend its rear tab for proper fit throughout the mounting bracket. It may also be necessary to bend the mounting bracket slightly.

SERVICE PROCEDURE:

1. Raise the vehicle on a hoist following proper lift procedures.

2. Allow the exhaust manifold and catalytic converter to cool.

CAUTION:

Exhaust manifold and/or catalytic converter may be extremely hot. Allow them to cool to avoid personal injury.

3. Reposition the exhaust manifold heat shield rearward insuring the full length of the rear tab is completely through the mounting bracket slot (Figure 1).

The rear tab is "folded". This "fold" should extend approximately 1/2 in. (12.7 mm) beyond mounting bracket slot.

4. Slide the heat shield inboard as far as possible within the mounting bracket slot.

5. Bend the accessible portion of the rear tab down to limit up and down movement of the shield.

6. Check heat shield for possible side movement and/or rattle.

7. If the heat shield can be moved and/or rattles, bend the mounting bracket toward the front of the vehicle and slightly upward snugging the mounting bracket against the heat shield.

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labor Operation: L2280

Use applicable labor time guide for labor hours.

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.