#07-06-05-001G: V8 Engines
Heat Shield Buzz During Vehicle Operation or Exhaust
Pinging/Popping/Snapping Noise (Normal Condition) When Vehicle Is Hot, At Idle or Immediately AFter Vehicle Is Shut Off - (May 7, 2010)
|Subject:||V8 Engines - Muffler Heat Shield Buzz During Vehicle Operation or Exhaust Pinging/Popping/Snapping Noise (Normal Condition) When Vehicle is Hot, at Idle, or Immediately After Vehicle is Shut Off (Perform Repair as Outlined Below)|
|Models:||2007-2010 Cadillac Escalade, Escalade Hybrid, Escalade ESV, Escalade EXT|
|2007-2010 Chevrolet Avalanche, Silverado 1500, Suburban, Tahoe, Tahoe Hybrid|
|2007-2010 GMC Sierra 1500, Sierra Denali, Yukon, Yukon Hybrid, Yukon XL, Yukon Denali, Yukon Denali XL|
|Equipped with the following V8 Engines:|
|- 5.3L (RPOs LC9, LH6, LMG, LY5)|
|- 6.0L (RPOs LFA, L76, LZ1, L96)|
|- 6.2L (RPOs L9H, L92, L94)|
This bulletin is being revised to update model years/models, add RPOs and a pinging condition. Please discard Corporate Bulletin Number 07-06-05-001F (Section 06 - Engine/Propulsion System).
Some customers may comment on a pinging/popping/snapping noise from underneath the vehicle at idle or immediately after the vehicle is shut off. Pinging/popping/snapping noise from the exhaust system during cool down is a normal condition. The noise may be intermittent depending on the outside temperature and or temperature of the exhaust system at the time of testing.
Some customers may also comment on a buzz noise coming from the muffler during vehicle operation.
As the exhaust system cools, the muffler shell and muffler internals contract at different rates. Pinging/popping/snapping noise from the exhaust system during cool down is a normal condition.
If the muffler heat shield straps are loose, the heat shield may be free to buzz.
DO NOT REPLACE THE EXHAUST SYSTEM COMPONENTS.
Exhaust Pinging/Popping/Snapping Noise:
This condition is normal to the muffler design and does not indicate poor quality or part failure.
Confirm the origin of the buzz by shimming (use metal shims) the straps tight and rerunning the vehicle. If the buzz concern is gone, then it is caused by the loose shield. Using the following procedure, install new straps to secure the heat shield to the muffler.
- Install three straps, P/N 10391259, so that the strap screw head will be located on top of the muffler.
Tighten the strap screw to 4 N·m (35 lb in).
- Cut off the excess strap material and bend the strap over the strap screw head.
Strap, Exhaust Muffler Heat Shield