Exhaust System Muffler Heat Shield Rattle/Clang (Modify Muffler Heat Shield)

Some owners may comment about a rattle/clang type noise coming from the rear of the vehicle. This noise is normally noticed when the vehicle is being operated at low speeds or after the engine has been turned off. The noise typically may occur 3 to 4 times within a 15 to 60 second interval.

This condition may be caused by thermal heating and cooling of the forward section of the exhaust muffler heat shield.

Following the procedure below, enlarge the front outboard attaching hole of the muffler heat shield to 9 mm (3/8 in) and reattach to the vehicle underbody with a rivet, P/N 15961818.

1. Raise and suitably support the vehicle.
2. Remove the catalytic convertor to muffler/exhaust pipe attaching bolts.
3. Disconnect the exhaust hanger insulators located rearward of the muffler.
4. Position the exhaust pipe outboard to gain access to the muffler heat shield forward outboard attaching rivet.
5. Remove the forward outboard heat shield to underbody attaching rivet.
6. Enlarge the forward outboard slotted hole in the shield using a 9 mm (3/8 in) drill. Only drill through the heat shield.
7. Reattach the heat shield to the underbody using a rivet, P/N 15961818.
8. Connect the exhaust hanger insulators to the exhaust pipe and position to the catalytic convertor.
9. Install a new catalytic convertor gasket, P/N 10275205.
10. Install and tighten the catalytic convertor to muffler/exhaust pipe attaching bolts.

Tighten
Tighten the bolts to 34 N·m (25 lb ft).

11. Remove the support and lower the vehicle.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: