Exhaust noise
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Laughing Gas
Joined: May 2007
Posts: 1,100
Likes: 0
From: Davis, Ca.
Exhaust noise
Ever since I got my 4in. exhaust I have had a vibration noise from it. It is a tinny vibration noise, like as if there was a small rock or even a socket or something like that in the pipe. There is not though. If I put alittle pressure on the pipe it goes away, or if I give it the smallest throttle increase you could give it goes away. It is at a flat idle only when it makes the noise. I know it is something harmonic, I just dont know how to get rid of it. Any help, please?
Senior User
Joined: Oct 2008
Posts: 466
Likes: 0
From: Ontario, CAN
Generally that noise is from the pipe touching the frame or cross member or the like. Start from the down pipe and work your way back until you find the spot. Loosen the pipe and pry the area over until it clears. Leave a wedge in there until you have the bolts tight and then see if it will stay clear after you pull the wedge. You don't need much clearance and hopefully this will be enough to solve the problem.
Post Fiend
Joined: Feb 2008
Posts: 10,977
Likes: 5
From: Lancaster, Pa.
I'm betting something hitting the pipe too. Like Patrick and Tyler, look around the crossmember area, mine was hitting there too. Here a pic 
You'll see that stick in there, tight plus look how close that trans member bolt is to the pipe.
You'll see that stick in there, tight plus look how close that trans member bolt is to the pipe.
Lead Driver
Joined: Dec 2006
Posts: 7,092
Likes: 145
From: San Diego, CA
I have had the same problem for a while now. One of those nagging issues that doesn't seem dangerous, but is just really annoying. It only does it at idle and I can only hear it when I'm outside the truck. I got under there and checked for clearances, tightness and all of the mounts and hangars. Nothing (which is surprising since I still have the stock exhaust). I can press my foot (lightly) against the outlet and the noise stops. I wonder if it could be something inside the muffler (baffle maybe)?
I was thinking of getting some of that flexible exhaust pipe and cutting my muffler out, but CA is starting smog testing next year.
I was thinking of getting some of that flexible exhaust pipe and cutting my muffler out, but CA is starting smog testing next year.
Senior User
Joined: Nov 2006
Posts: 174
Likes: 0
From: Raleigh, NC
I had the same issue with my new exhaust. It was hitting on the crossmember, and no matter how tight I made the clamps, it would work loose again soon after. I just ended up welding the downpipe-exhaust joint solid and it's been fine ever since.
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Laughing Gas
Joined: Aug 2008
Posts: 823
Likes: 5
From: Dallas, Oregon
Try adding another "hanger" by using wire to tie the pipe to the frame in places where it it unsupported. Do this one place at a time, and add just enough pressure from the wire to gently support the pipe. Sometimes you can eliminate a harmonic by changing the length of the "tuning fork". If the noise goes away, put a real exhaust hanger at that location.
The stock system has very long lengths of unsupported pipe.
The stock system has very long lengths of unsupported pipe.
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Post Fiend
Joined: Feb 2008
Posts: 10,977
Likes: 5
From: Lancaster, Pa.
If that is your problem, with the cross member, do like me and a few others did here, take it apart, this stinks but you know, hit the pipe with a ball peen hammer to put an indent where the bolt is hitting.
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
I replaced the u-clamps with band clamps. The only u-clamp I retained was the one for a hanger and it is behind a bad clamp that is on the pipe to pipe connection.The whole exhaust system is much more rigid and does not vibrate as much.
I got the band clamps from RockAuto.
I got the band clamps from RockAuto.
Thread Starter
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Laughing Gas
Joined: May 2007
Posts: 1,100
Likes: 0
From: Davis, Ca.
Generally that noise is from the pipe touching the frame or cross member or the like. Start from the down pipe and work your way back until you find the spot. Loosen the pipe and pry the area over until it clears. Leave a wedge in there until you have the bolts tight and then see if it will stay clear after you pull the wedge. You don't need much clearance and hopefully this will be enough to solve the problem.
Thread Starter
|
Laughing Gas
Joined: May 2007
Posts: 1,100
Likes: 0
From: Davis, Ca.
Try adding another "hanger" by using wire to tie the pipe to the frame in places where it it unsupported. Do this one place at a time, and add just enough pressure from the wire to gently support the pipe. Sometimes you can eliminate a harmonic by changing the length of the "tuning fork". If the noise goes away, put a real exhaust hanger at that location.
The stock system has very long lengths of unsupported pipe.
The stock system has very long lengths of unsupported pipe.
Senior User
Joined: May 2009
Posts: 161
Likes: 0
From: Canton, Georgia
Try hanging something heavy from your exhaust & see if the noise goes away.It could be something as simple as an old brake rotor attached with a coat hanger. Move the weight around until you find the "sweet spot" then weld a heavy piece of steel in place of your weight.
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