Exhaust Boom at 1500 RPM (Install Spacers to Exhaust Hanger)

Some customers may comment on an exhaust boom heard inside the vehicle at 1500 RPM. Customers may also indicate an exhaust pipe outlet to fascia misalignment.

Install one 2 mm (.079 in) thick washer on each stud (2 per side), P/N 11505463, between the bumper bar and the muffler hanger, using the following procedure:

1. Raise the vehicle.
2. Remove the two nuts securing the left rear muffler hanger to the bumper reinforcement bar, then lower the exhaust.



3. Insert a washer on each muffler hanger mounting stud, as shown in the figure, then raise the exhaust.
4. Install the muffler hanger mounting nuts.

Tighten
Tighten the nuts to 16 N·m (12 lb ft).

5. Repeat steps 2 -- 4 for the right rear muffler hanger.
6. Check alignment of the exhaust outlets, relative to the fascia.
7. If required, align the outlets by loosening the intermediate exhaust flange. Some adjustment is possible by applying upward or downward force on the exhaust pipe while the bolts are loose.
8. While holding the pipe, tighten the flange bolts.

Tighten
Tighten the bolts to 50 N·m (37 lb ft).

Notice: Very little adjustment of the exhaust outlets to fascia exists by this method. If the exhaust outlets are misaligned due to improper contouring or bending of the exhaust pipes, replacement of the muffler is required. Refer to the Engine Exhaust sub-section of the 2000 Service Manual for replacement procedures.

9. Lower the vehicle.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: