Noise Diagnosis - Under Vehicle (Exhaust Pipe Rattle)

Noise Diagnosis - Under Vehicle (Exhaust Pipe Rattle)





Symptom

Underbody rattle.

Possible Cause

The exhaust system intermediate pipe is hitting the cross brace.

Diagnosis

Look for witness marks on the pipe and cross brace. Minimum clearance between the pipe and the brace should be:

* For the 3800 V6 the specification is 19.0 mm (0.748 in)
* For the 5.7L V8 the specification is 14.0 mm (0.551 in)

Corrective Action
* Reposition exhaust system to provide minimum clearance using the above specifications.
* Loosen the slip joint, converter bracket hanger and take down pipe to manifold.
* Raise exhaust system with a single post jack.
* Retighten the system starting with the converter bracket, then tighten the take downs at the manifolds, lastly tighten the pipe clamp.