Gmt900 Exhaust Noises

Zembonez · October 20, 2007

My 07 Sierra (GMT900) exhaust system pops constantly as it heats up and cools down. Anytime I stop at a light I hear it making noise. I'm not talking about an engine exhaust noise... it sounds like metal expansion... maybe in a joint somewhere. Would you consider this to be normal or would you head to the dealer and complain? Does yours do it?

It's not really that big of a deal but I don't think it should do it. It is fairly annoying if you have the window down or the radio isn't on.

SLPR_04 · October 20, 2007

That is the sound of that stainless steel heating up and cooling down. I love that sound. You should here my Corsa system popping and cracking after a good hard ride. Ahhh, music to my ears.

MS3DALE · October 20, 2007

Heres a bulletin on this..........

Document ID# 1912556

Subject: Exhaust Popping/Snapping Noise When Vehicle is Hot, at Idle or Immediately After Vehicle is Shut Off (Replace Straps on Muffler Heat Shield) #07-06-05-001 - (03/05/2007)

Models: 2007 Chevrolet Silverado (New Body Style)

2007 GMC Sierra (New Body Style)

Condition;

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.

Cause;

As the exhaust system warms and cools, the muffler and the muffler heat shield expand and contract at different rates. The straps currently used to hold the exhaust shield in place may not be crimped tight enough to stop the muffler heat shield from moving.

Correction;

Replace the straps on the muffler heat shield.

Parts Information

Part Number

Description

Qty

10391259

Strap, Exhaust Muffler Heat Shield

3

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

L9712*

Strap, Muffler Heat Shield - Replace

0.3 hr

*This is a unique labor operation number for bulletin use only. This number will not published in the Labor Time Guide.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

SLPR_04 · October 20, 2007

I stand corrected.

MS3DALE · October 20, 2007

Yea,It was a common problem we saw on the GMT800's,I thought they would have had it solved on the new GMT900's but I guess there still having issues with it.

I don't hear my CORSA doing it at all,nor did I hear it on the last two trucks I had with CORSA systems.

Zembonez · October 20, 2007

Yea,It was a common problem we saw on the GMT800's,I thought they would have had it solved on the new GMT900's but I guess there still having issues with it.
I don't hear my CORSA doing it at all,nor did I hear it on the last two trucks I had with CORSA systems.

Thanks Rich.

Looks like something I should be able to address if it is just the heat shield. I've had import cars do it in the past but not as much as this truck. Otherwise I love the new truck. I'll probably tinker with it and see if I can get it to go away.

Zembonez · November 6, 2007

UPDATE.

I tweaked the clamps holding the shield to the exhaust and the popping is all gone. WOO HOO! Easiest fix ever. We'll see if it stays gone.

BigJayDogg3 · November 6, 2007

I know this is off topic but. . . Did you ever install the keyless entry on Fred II?

NathanL · November 6, 2007

How loud are you guys talking about? I noticed it popping when I stopped to get gas today, but nothing you would ever hear inside the truck.

Zembonez · November 6, 2007

I know this is off topic but. . . Did you ever install the keyless entry on Fred II?

I can't find anybody that can tell me what I need. I sure do want to. Got any ideas?

Zembonez · November 6, 2007

How loud are you guys talking about? I noticed it popping when I stopped to get gas today, but nothing you would ever hear inside the truck.

It was just a popping noise from the heat shield heating and cooling. Not too loud just annoying. It's gone now!

RyanZ71 · November 6, 2007

my 07 does it as well, very annoying, my 99 never had that problem. I'll be crawling under to see if I can tighten the shield a bit more to resolve that.