Exhaust Manifold Heat Shield - Rattles

91chevy24

Number: 91-421-6F

Section: 6F

Date: SEPT. 1991

Corporate Bulletin No.: 166604

ASE No.: A8


Subject: EXHAUST HEAT SHIELD RATTLE


Model and Year: 1988-91 S1/T1 TRUCKS WITH 4.3L ENGINE

Figure 1:

Some 1988-1991 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.