Subject: | Exhaust Popping/Snapping Noise When Vehicle is Hot, at Idle, or Immediately After Vehicle is Shut Off (Replace Muffler Heat Shield) |
Models: | 2002-2006 Cadillac Escalade, Escalade EXT |
2003-2006 Cadillac Escalade ESV |
2002-2006 Chevrolet Avalanche, Suburban, Tahoe, Silverado, Silverado HD |
2007 Chevrolet Silverado Classic, Silverado HD Classic |
2002-2006 GMC Sierra, Sierra HD , Yukon, Yukon Denali, Yukon Denali XL |
2007 GMC Sierra Classic, Sierra HD Classic |
2003-2006 HUMMER H2 |
with 4.8L, 5.3L, 6.0L or 8.1L Gasoline Engine (VINs V, B, T, Z, N, V, G -- RPOs LR4, L33, LM7, L59, LQ9, LQ4, L18) |
This bulletin is being revised to add the 2006 and 2007 (Classic Only) model years and the 5.3L (L33) engine. Please discard Corporate Bulletin Number 03-06-05-008C (Section 06 -- Engine/Propulsion System).
Some customers may comment on a popping/snapping noise from underneath the vehicle at idle or immediately after the vehicle is shut off. Some 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.
As the exhaust system warms and cools, the muffler and the muffler heat shield expand and contract at different rates and may cause a popping and/or snapping noise.
Some popping/snapping noise from the exhaust system during cool down is a normal condition. The customer should be made aware that this service procedure is designed to reduce but not eliminate all exhaust system popping and snapping during cool down.
DO THIS | DON'T DO THIS |
---|---|
Install a new heat shield and straps on the existing muffler. | DO NOT replace exhaust system components other than the muffler heat shield. |
Follow the service procedure below to correct this condition.
Important: Some popping/snapping noise from the exhaust system during cool down is a normal condition. The customer should be made aware that this service procedure is designed to reduce but not eliminate all exhaust system popping and snapping during cool down.
Caution:
• In order to avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool. • Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges could result in serious personal injury.
Important: Do not use oil base lubricants on the rubber exhaust hangers.
Important: It is not necessary to remove the muffler from the vehicle to replace the muffler heat shield.
Notice: Use extreme caution not to damage the muffler when removing the heat shield from the muffler.
Important:
• The new heat shield should not come in contact with the remaining muffler heat shield. • The new heat shield should not come in contact with the horizontal lock seam on the muffler.
Tighten
Tighten the strap screw to 4 N·m (35 lb in).
Important: ONLY 6.0L and 8.1L equipped vehicles require a new exhaust pipe clamp, P/N 15103174.
• | The inner diameter of the exhaust pipe hanger |
• | The exhaust pipe hanger rod |
Tighten
• | Tighten the muffler nuts by hand until each contacts the metal flange. |
• | Tighten the muffler nuts to 45 N·m (33 lb ft). |
• | On 6.0L and 8.1L equipped vehicles only, tighten the exhaust clamp to 50 N·m (36 lb ft). |
Part Number | Description | Qty |
---|---|---|
15253526 | Shield, Muffler Heat Shield (24 inch shield) with 4.8L or 5.3L engine 1500 Series Base Utility Trucks ONLY | 1 |
10393433 | Shield, Muffler Heat Shield 28 inch shield with 6.0L engine (LQ4, LQ9) H2 or 1500 Series Luxury Utility Trucks ONLY | 1 |
15808181 | Shield, Muffler Heat Shield 25 inch shield with 6.0L or 8.1L engine (LQ4, LQ9, L18) 2500 Series Utility, HD Pickups and Luxury Pickup Trucks ONLY | 1 |
15103174 | Clamp, Exhaust Pipe with 6.0L or 8.1L engines ONLY | 1 |
10391259 | Strap, Muffler Heat Shield Strap All Vehicles | 3 |
15103184 | Clamp, Exhaust Pipe (pipe size 2.75") (25 Series Suburbans/Avalanche and 8600 lb. 25 Series Pickups w/LQ4) | 1 |
15102680 | Clamp, Exhaust Pipe (pipe size 3") (25 & 35 HD Pickups w/LQ4 or L18 engines) | 1 |
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
---|---|---|
L2540 | Shield, Muffler Heat Shield - Replace | 0.8 hr |