Rattle from exhaust

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Milwaukee, WI
So the other day I was getting ready for a car wash, rolled the window to pay attendant. And there was a rattling coming from under the car. As soon as the car wash was over I pulled over and found the noise coming from mid/ back of car and when I revved the car up it got louder and almost sounded like it backed fired. Any ideas what it might be? I did do search found a few threads but where close to a year old not sure how the mods feel about necro bumping.


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Not sure, the almost backfire sound throws me way off, and chance you can post a sound clip? Might be easier for someone here to diagnose.
 
My guess is this:

It's a 2004. You are from WI. Salt has eaten away some part of a clamp or some metal that was either bolted or most likely sodered to the exhaust. Bring it to an exhaust shop and after you lift it you should see right away what piece has gotten loose. Should be very quick fix.

Worst case there is an actual hole in the exhaust which maybe explains a little backfire, but that would be much more unlikely imho unless the salt has really worked it's magic and don't wash the car much.
 
jdTrader said:
My guess is this:

It's a 2004. You are from WI. Salt has eaten away some part of a clamp or some metal that was either bolted or most likely sodered to the exhaust. Bring it to an exhaust shop and after you lift it you should see right away what piece has gotten loose. Should be very quick fix.

Worst case there is an actual hole in the exhaust which maybe explains a little backfire, but that would be much more unlikely imho unless the salt has really worked it's magic and don't wash the car much.
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But it would be louder with a hole in da muffler not?
 
i didn't say muffler I said exhaust pipe, but I think that is rare. I think salt just ate away at something that had a week soder point and usually that can be fixed very easily.
 
I just installed a new muffler a couple weeks ago and shortly thereafter developed an awful rattling sound. After lots of listening and banging my fist into various parts of the system I found that the new muffler was defective and a piece of the internal structure had come loose, causing my rpm-specific rattling. Under ~50% throttle around 2k rpm it sounded like a normal high frequency metal-to-metal rattle, but since it was occurring just before the pipes on the inside, the sound was amplified significantly. Try smacking different parts of the system with your hand. You may at least be able to isolate the sound that way...
 
This morning I started the car and notice some exhaust smoke(or heat steam?) coming from midway up the the exhaust pipe I will post a picture from where when I get home. The rattle noise does gets louder as the car warms up more. And I do try to keep the underside of the car clean with regular washes in the winter


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Just an update finally had the time to get this checked out today. The muffler shop said the center pipe has come dislodge from the rear muffler and told me I had to replace the center pipe AND rear muffler this didn't make sense to me but before I dropped any coin wanted to make sure this was true I know they sell the center pipe separately and would think that's all that needs to be replace. Any thoughts
 
Advantage said:
Just an update finally had the time to get this checked out today. The muffler shop said the center pipe has come dislodge from the rear muffler and told me I had to replace the center pipe AND rear muffler this didn't make sense to me but before I dropped any coin wanted to make sure this was true I know they sell the center pipe separately and would think that's all that needs to be replace. Any thoughts
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It depends on what the shop meant by "center pipe". Did they show you the problem?
 
Yeah it's the pipe that connects the cats to the muffler it has a muffler in the center of it. Problem is the end of the pipe that connects to the rear muffler has rusted pretty bad. If you look on infinit parts web site it's number 7 on the diagram.

http://www.infinitipartsusa.com/parts/2007/INFINITI/FX35/?siteid=55&vehicleid=1434522&diagram=3850215
 
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You may be able to have a muffler shop cut away the rusted out area before the flange (where the midpipe bolts to the muffler). Then have them cut the muffler flange, and weld a piece of pipe in to connect the midpipe and muffler. It's a quick and inexpensive fix. I did that before replacing my exhaust.
 
kruelhouse said:
You may be able to have a muffler shop cut away the rusted out area before the flange (where the midpipe bolts to the muffler). Then have them cut the muffler flange, and weld a piece of pipe in to connect the midpipe and muffler. It's a quick and inexpensive fix. I did that before replacing my exhaust.
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+1. The dealerships don't fix things, they only diagnose and replace things. Its an easy fix (less than $100), you just need to find a competent muffler shop.

EDIT: I just realized you in fact went to a muffler shop... To revise my advice above, you need a BETTER muffler shop. ;)
 
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I took it to this mom and pops place they looked and said bring it on Tuesday we should be able to cut it and put pipe to repair it I said he if you can do this I'm buying pizza for the whole shop!!!
 
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