Muffler "popping/snapping" noise

[mikenmo23]

Hello. I am a new '04 Z71 Avalanche owner and I have been in and out of the service department with a few bugs being worked out of my truck. (bumper repainted,new steering gear.) I have 3500 miles on it and for about 2000 miles now it has been making what they call a popping/snapping noise comming from the muffler. GM is aware of the problem (it's NOT normal) and has issued a bulletin for quite a few GM model from 99-04 with this problem. They are working on a fix and the bulletin says NOT to replace the muffler. (yet) I asked for my muffler to be replaced but they wont do it. How did you guys get yours replaced My other question is should I just go out and buy a Flowmaster and would this solve my "bonging" noise? I hate to spend the $$ when it's technically their warranty problem. Please help! Thanks!

 

[tjchr]

Its not the muffler its the cat, mine does the same thing especially with the 10-20 degree temps here in jersey, all it is, is the material inside the cat transfering energy with the big difference in temps between outside air temp and the exhaust temp.

 

[mikenmo23]

so, you are living with it Are you sure your is making a really loud "bonging" noise? I mean, I can hear mine inside the house for about 5 minutes after I come home. Not to mention in parking lots I have gotten a lot of strange looks and I dont even have the cladding

 

[ygmn]

Welcome to the club...

I moved your thread to the Q&A section....

I suggest checking out the other threads in this section which refer to the same problem as yours...look for Exhaust BONGING....or similar....

in these threads are some answers to your questions...

Good Luck

 

[VMAX]

It's the muffler and it's not normal (about drove me insane , dealer replaced mine, thankfully). I would suggest trying a different dealer. The exhaust is stainless steel and should last the life of the truck, it would be ashame to replace part of it with a non-stainless aftermarket item if you are otherwise happy with the stock exhaust.

Here are 2 other threads on this:
http://www.chevyavalanchefanclub.com/cafcna/index.php?board=15;action=display;threadid=5574
http://www.chevyavalanchefanclub.com/cafcna/index.php?board=15;action=display;threadid=18035

 

[sands611]

Replace with a CAT BACK from CORSA (Stainless) and you are good to go.
It is really nothing though. Just the CAT adn Muff creaking after temp differences is all-
It is a charachter flaw, thats all...
LOL

 

[BADalanche]

I noticed mine makes a "popping, hissing noise" when I park in the garage after I have been using the auto-climate sytem. Even when I am using heated defrost, the auto AC will turn on the compressor. All of the condensation from using the AC drips out of a drain hole uder the hood directly on to the hot exhaust. It makes a pop/hiss sound like when you drip water on a hot iron. Never happened in my last GM, but I didn't have the auto AC either. I assume its normal and won't hurt anything.

 

[mikenmo23]

Yeah, I know the sound you are talking about and mine is not that sound. Mine is a big loud BONG!......BONG!....the GM people call it a popping/snapping noise but it's not. I am going in for my first oil change here soon and will make sure it's nice and warmed up for them so they will hear it. Hopefully I can get them to replace the muffler or cat or anything to get rid of this sound. It's driving me nutz!!!!

 

[MisterScott]

My new 04 Z71 makes the same noise. I remember a guy telling me the H2 made the same noise. Much louder than the normal exhaust cooling/contraction that happens at shut down. The H2 owner was really ticked at laying out all that cash for a vehicle like that and when he parked it sounded like it was falling apart.

 

[GoldBowTie]

Mine started doing the same thing last summer (about 20 months into ownership.) It sounded like someone popping the dent out of a 55 gallon drum.

It has since stopped, so I'm not sure what is up with that.

 

[ewallace]

My 04 has around 1100 miles and I noticed right after parking in the garage. I just thought it was the "normal" cooling down, being new and all. Did think it was exceptionally loud, though, and figure it will go away. Thanks for the info that it is a problem and I will continue to monitor it.

 

[MisterScott]

As an addition, I notice mine does it when I stopped at a light with the motor running and in gear. On the grand scheme of things, it is minor, it is minor and not performance oriented. But it can get pretty loud after you park.

 

[ICEMAN316]

I just got my AV back from the dealership for the loud clicking noise when i turn at low speed and i asked them about the loud "bong" noise and he said GM knows about it but they were told by them not to do anything.I really hope they do something about it soon..

 

[Rick M]

Yep got the muffler bong here too.This is really quite loud and annoying,can here it driving slow or at a stop or after I park it.

 

[sthomp22]

I have the same thing. Poping, binging. Drives you Crazy. I have someone looking into it. I also found out the buicks were doing the same thing GM didn't want to replace it. They caved and they were being replaced. hopefully they will cave on the av to.

 

[MisterScott]

Spoke with my service manager today about this. GM is supposedly working on a fix. They are aware of the issue in some late model GM trucks. He claims it is not the cat, but related to the metal used in the whole exhaust system. If you want to be notified when a fix is out, he said call GM and have your name added to a list. For what it is worth.

 

[ChampioN]

I am having the same problem. My dealership has replaced the muffler 2 times now and it still has not fixed the problem. It is louder now than ever. Like others have said, I can even hear mine while driving 30 mph down the road. Very annoying. I hate having spent this much money on a vehicle and it sound like it is falling apart.

 

[mikenmo23]

UPDATE!!!!

Earlier this year I had been in contact with someone at GM who told me that they will have a fix come late spring '04 for the muffler "popping/snapping noise". I emailed them a couple weeks ago to see how the fix was coming along and today I got an email from the same GM guy (Bob Savo) asking for my vin# and dealer name and they are going to address the problem. Makes me think they might actually replace my muffler now. Yeah! Hopefully no more bong noise....although I have to say that I am pretty much immune to the sound now. I only notice it after I park and get out of the car. I'll let you guys know if/when they fix it, too.

Wish me luck!

monique

 

[JDEANZ]

Here's how i fixed my bong noise;

 

[cadboy1]

I only notice it after I park and get out of the car. I'll let you guys know if/when they fix it, too.



monique

Thats the only time I hear mine. I will live with it until I decide on what exhaust system I want. I am leaning toward the dual Borla.

Mike

 

[Shylok's]

Hello. I am a new '04 Z71 Avalanche owner and I have been in and out of the service department with a few bugs being worked out of my truck. (bumper repainted,new steering gear.) I have 3500 miles on it and for about 2000 miles now it has been making what they call a popping/snapping noise comming from the muffler. GM is aware of the problem (it's NOT normal) and has issued a bulletin for quite a few GM model from 99-04 with this problem. They are working on a fix and the bulletin says NOT to replace the muffler. (yet) I asked for my muffler to be replaced but they wont do it. How did you guys get yours replaced My other question is should I just go out and buy a Flowmaster and would this solve my "bonging" noise? I hate to spend the $$ when it's technically their warranty problem. Please help! Thanks!

Mines doing the same and I have a 02 z71. Did they fix it and did you find out why or what to do, I'd like to know please. I'm not the original owner & bought it used so can I still take to a dealer to get part changed out if they found out their part is faulty?

 

[Randy]

I doubt it the post is almost 18 years old...