Hey guys,

I was just wondering if maybe you could help diagnose this loud ass rattle that i've developed over the last month or so. It's defintely coming from under the car, and it only does it after the car warms up. I do hear it sometimes when i first start the car (Like that first second when the car actually fires). It almost sounds like a heat shield is rattling around. I got under the car and looked over everything the best that i could (It is like 10 degrees here) and i didn't see anything hanging loose. Now one thing i did notice is that right were the DP comes down and before it straightens out to go to the cat, it goes over this cross bar. It's super close there to the point to where i couldn't even fit my finger between the two, but i tride to jerk the pipe down to see if it would hit and it didn't. Is anyone else experiencing this? Is it because of the cold weather? It only does it after i've drivin for a bit and let things warm up. But if it sets and idles for like five minutes or so and cools down it kinda goes away (Not AS loud). Thanks for reading and hopefully you can help me figure this out.

Edit: I forgot to mention that i really notice it in the lower RPM's and mostly when i hit third, or first taking off in first.
Thanks,
Dave

 

Sounds like you are looking in the right place. Exhaust pipes and heat shields knocking around do make a lot of racket. Check those heat shields again. They attach in several places, and if just one spot is loose, that will make a lot of noise. The shield will still be tightly in place due to the other attach points.

 

check and see if there is a leak coming from the part of the down pipe that bends. the flex part. that what mine did before it cracked

 

i made the same thread about 3 weeks ago, i am taking it to gm for the EXACT same problem, right around 3000rpm in 1st and 2nd, i hate it kuz it makes your car sound crappy, im almost positive it is heat shield or exhaust hanger, i will for sure let you know this week after the dealership

 

Yeah it sounds like i'm driving around in a rusted up honda. Yeah deffinetlly let me know what you find out right now it's like 15 degrees here and i'm not looking to forward to getting underneath there.

 

I have the exact same rattling noise. I've taken my to the dealer two or three times for this noise and they keep telling me they can not locate / duplicate the noise.

 

When did your guys start? Was it just when it started getting cold or has it been an ongoing thing?

 

minestarted in november, and it kind of escaladed, today i havent had one little rattle, but some days it rattles pretty bad the whole day in 1st n 2nd

 

Mine pretty much started back during the summer. Like tombomb it's mainly in 1st and 2nd. Then again I don't hear the rattle everyday. That is what makes it so irritating.

 

Mines an everyday thing, it's gotta be an exhaust thing for my case. i just wish it would warm up enough to get underneath there again to check it out. It's just wierd how it only does it after i've driven it for a while.

 

The problem I have with my noise which sounds like all of yours with the clunking or knocking or rattling is occasional but annoying it sounds like something is loose it only seems to happen within a couple miles after I get off the highway either going straight or turnings and then gets rapid and louder if I speed up. The dealership can't pinpoint unless they can duplicate it but of course it dosent do it when its there. I will stop by the dealership tomorrow and have them check a few things of what I have read about here and see what happens.

 

I was under the car looking and still didn't see anything, but one thing i did notice was that i have a little bit of a clearance issue with my downpipe. In the picture below i notice that there is a lot of room between the CAT and the bar that goes across there. I can't even fit my finger between the two. Is this normal to not have that much clearance or is there something majorly wrong?

Click on pic to enlarge.

I couldn't find a pic of the bar and DP until i stumbled upon this one on TAG's website. If you have a problem with me using it for an example let me know and i'll be happy to take it down.

 

yeah i have the same noise on my im going to look at it tonight.

 

i live in buffalo and i have been hearing the same noise lately since its been so cold. i mean its loud, but its not loud enough to hear w/ the windows up, so i don't know if i'm hearing the same thing as you are.

 

Yeah, it's hard to hear with the windows up but once i roll them down i can hear it pretty well.

 

i started to notice a few days ago..i went out just now and checked it out...it only happens when the coolant is at 80 degrees or more which is basically my normal..car sounds like the other guy said..a busted honda...makes me feel like **** now..i tried to see where it was coming from...i thought it might b coming from the supercharger but i don't think so...then i listened closer to the engine sounded like a bolt was loose or something although i never checked the wall or any thing like u guys are saying so maybe its that but sounds ilke its coming from inside the engine though (however i have only noticed it during idleing) only have 3k KM'S not miles KM'S...thats like just under 2k miles

 

See mine doesn't do it durring idle it does it when you get a vibration from being in to low high of a gear and take off. Mine sounds like it's coming from between the cat and res so now that it's starting to warm up this week i'm going to check it out a little more extensive. But damn it's annoying.

 

mine kinda rattles too, but its like a plastic sound. im not too worried about it though.

on my cavalier it does that too, so i got under it and its that black valence sheild thingy cause it broke while pulling out of a driveway.

 

The dealership may believe its my exhaust pipe that goes from cat to muffler. They ordered a piece and when they fix , I'll see if thats the problem.

 

I had that same rattle in my van when i first started it up.
Ended up being the internals of the cat rattling until heat expanded it.

 

I'm having the exact same problem with mine...knocking/rattleing sound from under the car. But it only happens every once and awhile. I took it to the dealer the other day (for the recall) and told them about it and he said it sounded like an exhaust problem. I didn't feel like waiting around for them to really check on it, so I have yet to have it diagnosed.

 

As far as i can tell its a lose baffel rateling around in the muffler.

 

i had a rattle develop after i put my exhaust and downpipe on... though i couldn't SEE it, i felt along the pipe and sure enough the heat shield was toughing in a tiny spot on the downpipe... bent it back with a screwdriver, problem solved.

 

Just a bump to see if anybody else is finding anything out. As far as i can tell nothings making contact with the exhaust, but keep the comments coming as i might find something new.

 

Well i got bored so i thought i would go take some pictures of some of the things i noticed while trying to research the noise i'm hearing. Here are a few pics.

DP & Cat


DP & Cat Clearance (I can't fit my finger between the two in this pic.)


Heatshield (Is there supposed to be another clip in the second hole?)