Heat Shield Buzz Heard While Driving GM Trucks
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 muffle: 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.
Why Muffler Buzz
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 Muffler Buzz
Confirm the origin of the buzz by shimming (use metal shims) the straps tight and start the engine, 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 muffle:.
1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in Owners Manual.
Auto Muffler Strap
2. Mark the position of the heat shield (1) and straps (2) on the muffler shell.
Vehicle’s heat shield – Remove Muffler Strap
3. Cut and remove the heat shield straps using tin snips along the muffler shell seam (1), and remove the shield from the muffler.
4. Position the heat shield to the muffler and install new heat shield straps on the muffler shell in the positions marked prior to removal.
Install New Muffler Straps
Do Not position the strap screw heads directly across from the propeller shaft. Ensure the strap heads are positioned below the midpoint of the muffler. Position the strap screw heads (1) on the inboard side of the muffle:. Ensure that the strap screw heads (1) are below the midpoint of the muffler. Tighten the straps to 4 Nm (35lb.in). Cut off the excess strap material and ensure that the ends (2)are flat against the muffler.
Description: Strap, Exhaust Muffler Heat Shield
Qty: 2 or 3
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)
2007-2011 Cadillac Escalade. Escalade Hybrid Escalade ESV, Escalade EXT
2007-2011 Chevrolet Avalanche. Silverado. Suburban. Tahoe, Tahoe Hybrid
2007-2011 GMC Siena, Sierra Denali, Yukon, Yukon Hybrid Yukon XL, Yukon Denali, Yukon Denali XL
Equipped with the following V8 Engines:
- 4.8E RPO LY2, L20)
- 13E RPOs E9, LH6, EMG, LYS)
- 6.0E (RPOs EFA, EY6, LZ1, L96)
- 6.2L (RPOs E9H, L92, L94)
Please Refer to GWI1IVH
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