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Loud airy/rattle noise when accelerating? Please help!

11421 Views 5 Replies 4 Participants Last post by  00chevy53
I hope I am posting in the right place, first time to post here :great:. I have a 2010 Silverado Extended Cab Texas Edition. I had a Cherry Bomb extreme muffler installed, and everything was working perfectly for a little bit. However, I have started to notice recently an obnoxious noise when accelerating and crusing. I will do my best to explain it, but we all know how hard noises are to explain. For one, I know it is coming from the engine compartment, not behind it in the rest of the exhaust system (so I assume it has nothing to do with my muffler?). If you put your head down by the break pedal, you can easily hear that the noise is coming from in front of you. The noise can be heard when started up cold for about 15 seconds at idle, then it subsides until you start driving. Now to try and explain the noise. The noise is a very airy noise that almost sounds like a rattle at times. It can be heard when accelerating and cruising. It can be heard the loudest when at approx 2500rpms or when the vehicle drops to 4 cylinders and you are just cruising (then it almost turns into an airy chirpy noise). Now I know that aftermarket mufflers will be louder in the cab and sound weird when dropping to 4 cylinders, but this airy noise is completely different. The noise is extremely annoying, and I wish I could explain it better. I took it to my dealership and they said it was simply a result of having an aftermarket muffler installed. I have had previous work done at this dealership that I was less than impressed with, so I take their opinion with a grain of salt. I just need to be able to tell them exactly what the issue is so they will fix it. I have owned and driven other vehicles with cat back mufflers and never experienced or heard anything like this (even other GMs that have the V8/V4 switch), I am almost 100% certain it has nothing to do with the muffler since it is coming from the engine compartment. I am sorry for the long read, but please lend any advice. I paid to much for a truck to annoy the heck out of me every time I drive it! Thanks for the help!
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Have you tried contacting another dealership in the area? I can also look into this further. In order to do so, I will need the VIN and current mileage. Please feel free to contact me via private message and I will be happy to do further research. Thank you in advance.

Tricia, GM Customer Service.
try checking your exhaust manifold gasket... i know it shouldnt be bad but you never know. when the engine has been setting for a while and is cool take a can of starting fluid and turn the truck on and spray around where the gasket is and if the motor revs up a lil then you know the gasket is bad and has a leak...
Did you save your stock muffler? If you did I would reinstall it and see if the noise goes away. I know it alot of work but you would have your answer. Also try tightening your exhaust sheilds under the truck and in the engine compartment.
I do still have the stock muffler, but that is a lot of work to weld it back in (cherry bomb wasnt a bolt in) just to confirm it isnt the problem. I may use it as a last resort, but the noise is coming from up front which logic tells me can't have much to do with the muffler. I could be wrong but I would rather try some other options out before resorting to that.

I will try spraying the starter fluid. Quick question though just for personal enlightenment. Why does the motor have to be cool, and will I hear the engine rev noticeable higher or will I really have to listen for it? And are the exhaust manifolds easily accessible from underneath the truck?

Thanks for the help!
it needs to be cool because if its hot when you spray it you could catch your engine on fire. the exhaust manifold (header) will be on the sides of the motor and your spraying between the heads and the header.

---------- Post added at 03:07 PM ---------- Previous post was at 03:06 PM ----------

yes you should be able to hear it since you have an aftermarket exhaust
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