GM Service Manual Online
For 1990-2009 cars only

Tail Pipe Depressions- Incorrect diagnoses of poor fuel economy or engine performance - keywords bent crushed exhaust flat tailpipe

Subject:Tail Pipe Depressions

Models:2007-2008 Chevrolet Silverado
2007-2008 GMC Sierra
With 6.6L RPO LMM Engine



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some owners may comment of poor engine performance or high fuel consumption. When inspecting the exhaust system they may notice depressions in the tail pipe, as shown in the area below. These depressions are design-intent and purposely created to provide production tooling clearance during the assembly of the vehicle. The clearance depressions have a minimal impact on the overall exhaust system back pressure and therefore have no affect on fuel economy performance.


Object Number: 2065320  Size: SH

Recommendation/Instructions:

Do not replace the muffler/tail pipe assembly when these depressions are the only finding. The service muffler/tail pipe assembly without depressions offers no advantage or benefit over the assembly with depressions.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.