Strange vibrating noise when it rains!!!

[MetRx]

Ok guys, im stumped. Whenever it rains, my car makes a vibrating noise from underneath the chassis. Sounds like metal banging on metal. I think it has something to do with my exhaust. I have a thermalRD cat-back system on now. I dont recall it doing this before. Its a pretty bad noise, and im afraid im gonna damage something under the car. It only does this when it rains. Tomorrow im gonna jack the car up, and see if i can see any visible spots that have been rubbing the chassis, or anywhere underneath the car. Im gonna be really mad if i have to take this thermal exhaust off my car. Any ideas? or ever heard of anything like this?

Matt

[MetRx]

Oh, and by the way, this is my theory. I think that when it rains, maybe water is getting into the muffler because of the large opening, and causing the muffler to hang lower and raise the rest of the pipe up to hit the chassis. Is this far fetched? I gotta figure this out, its driving me NUTZZ!

Matt

[DyNastySi]

Man I thought I was the only one. I get the same vibration also. It only started to happen once I got my mid pipe put in. The guys over at 7thgen say it could be two things. Water hitting the cat is one, and also water getting in between the bushings. Try going to 7thgencivic and doing a seach on exhaust vibration.

[MetRx]

Hey, thanks for telling me about that site. I really thought i was alone with this problem. It pisses me off soo bad im ready to go traded this damn car in. If this problem doesnt get fixed i'll be driving something different this winter. Im not putting up with this!

Matt

[ALCT]

i had the same problem a week ago on a rainy day. I was cruisin on the highway suddenly I noticed this knocking sound coming under the car with some vibration. I thought I was losig the cat back. it was for 10 seconds and never happened again.

[LazyAzzAzian]

i have the exact same problem, i have a tanabe racing medallion and everytime it rains significantly the midpipe makes a crazy banging noise. it sounds like the midpipe is hitting the bottom of the car.

[chet]

Same for me. . .Thermal. Theory: The rainwater acts as a "conductor" of energy between two different vibrations--1) the chassis and 2) Engine+Exhaust, etc. etc. So, where you normally have "space", now you do not. And yes, I do need to quit smoking that shit:cool:

[ballsdeep]

Holy sh!t I'm not crazy. Its only happened twice but both times it was raining. Its sounds like its coming from undreneath the car directly below the emergency brake. It sounds like something is vibrating really bad but then I cant get it to do it again and everything underneath my car seems to be ok. I also have a midpipe.

[civicpimp]

So is there a solution to this problem because my Borla does the same thing. I guess this is happening with many of the aftermarket exhausts.

[MetRx]

This noise cant be my exhaust. I jacked the car up, and theres NO sign of rubbing, or contact anywhere. In fact, my thermal exhaust is on there soo snug, you cant even force it to hit the bottom of the car. So theres NO way rain is doing that. I just want to know what it is so i can fix it! Warranty, or not, that noise has gotta go. The next time it rains, im just parking my car, crawling under it while its running, and finding that damn noise. Man, it makes me soo angry i wanted to trade the car in. If im ever out driving when it rains again, im going straight to the dealer, and tellin the service guy to get in. We gotta figure this out. I might even just start my car up this week, and get out the hose. Have my buddy go to town sprayin the undercarriage, and motor compartment while its running. Any more thoughts on this. We all apparently have this problem, we gotta figure it out.

Matt:D

[simione]

i had the same problem and i had thermal on my 01 ex coupe and on the si too. whats happening is that the triangular flange on both of my cars did not seal completely. when i started the car when it was on jack stands i would put my hand near the flange and air was leaking out of it. thermal uses very thin flanges. i think when it rains water gets between this flange because when you let off of the gas it creates a vacuum right there and it sucks water up there and it gets into the exhaust. try puting the car up on jack stands anf feeling for a leak. that was my problem. i sol the thermal and got greddy and the greddy has never done it. the flange is substantially thicker too. hth

[02SilverSiHB]

Originally posted by simione
i had the same problem and i had thermal on my 01 ex coupe and on the si too. whats happening is that the triangular flange on both of my cars did not seal completely. when i started the car when it was on jack stands i would put my hand near the flange and air was leaking out of it. thermal uses very thin flanges. i think when it rains water gets between this flange because when you let off of the gas it creates a vacuum right there and it sucks water up there and it gets into the exhaust. try puting the car up on jack stands anf feeling for a leak. that was my problem. i sol the thermal and got greddy and the greddy has never done it. the flange is substantially thicker too. hth
that sounds exactly like what it is. My comptech exhaust did this. I was pissed, but I just went and bought a mr.gasket and put it in that triangular area of the flanges (between the cat and mid pipe) comptech doesn't come with a gasket and neither does the stock one.

[MetRx]

Ok, but what about the people on 7thgencivic that have stock exhaust and have the problem. I'll take a look and see if i have an exhaust leak. I just want it fixed. It pisses me off driving a new car that sounds like hell.

Matt

[02SilverSiHB]

Originally posted by MetRx
Ok, but what about the people on 7thgencivic that have stock exhaust and have the problem. I'll take a look and see if i have an exhaust leak. I just want it fixed. It pisses me off driving a new car that sounds like hell.

Matt
are these the 01 coupes/sedans? if so, I wouldn't compare to that since they have a different exhaust setup.

[MetRx]

Ok guys, this is crazy. Sooo many people with this problem, and soo many different solutions. On 7th gen civic, some guys are saying they changed the header, and it went away. While others are saying its the mid pipe, and that it needs to be bent differently. WTF????

Matt

[02SilverSiHB]

Originally posted by MetRx
Ok guys, this is crazy. Sooo many people with this problem, and soo many different solutions. On 7th gen civic, some guys are saying they changed the header, and it went away. While others are saying its the mid pipe, and that it needs to be bent differently. WTF????

Matt
well have you got under the car while it's running to see if there is an exhaust leak. Don't blame the car, you do have an aftermarket cat back exhaust on.

[MetRx]

Im not blaming the car, or anybody. I just want to know what the noise is. I hear soo many different theories on this problem. You really need to visit the other civic sites to hear what others have to say about it. For that matter, i'll go check for the exhaust leak right now. Do i think its possible that it can cause that noise? Not likely!

Matt

[MetRx]

I just went out and checked for an exhaust leak. We cant hear, smell, etc. any exhaust leak. We took the hose to the undercarriage of the car, no noise. Any other suggestions? We also popped the hood and sprayed EVERYTHING. No noise. What about the heat shields? Anybody ever tried removing them?

Matt.

[02SilverSiHB]

Originally posted by MetRx
I just went out and checked for an exhaust leak. We cant hear, smell, etc. any exhaust leak. We took the hose to the undercarriage of the car, no noise. Any other suggestions? We also popped the hood and sprayed EVERYTHING. No noise. What about the heat shields? Anybody ever tried removing them?

Matt.
hhhmmm, strange. This is a crazy idea and could be dangerous, but let the car run for a while, maybe even drive it around like crazy. Then get a water hose and start spraying under the car to see if you hear anything and maybe find out where it's coming from. I say dangerous because of the heat from the steam coming off the exhaust.
When this happened, did you only hear it when it was raining and you let the foot off the gas while either coming to a stop, or even just at a stop light and it started making the sound. And when you heard the sound, did you feel it in the car, and at some point it almost sounded like thunder?

[MetRx]

Well, i will try that next. If it rains, im going for a ride. Im gonna get out of the car, crawl under it, and find that noise. It happens when it rains, sounds like someone is rattling an aluminum baseball bat between the engine and the chassis. When im driving, it feels like its right under the car, between the seats. Oh, and when it starts doing this, it will do it while im driving, or at idle. Another note here, is that one time it did it from driving thru mud puddles on a bumpy gravel road. It wasnt raining that time, just wet roads. Any advice here is appreciated. This noise seems pretty violent when it happens, and i cant imagine it being good for the car. Other people on 7th gen say they sometimes get the noise when they are accelerating really hard. Mine NEVER does that. Only when wet. Its just bothering me because soo many people on other sites CLAIM they know what the problem is. I've heard soo many different answers, its driving me nuts. Example! Somebody mentioned motor mounts???? WTF! Explain that to me.

Matt

[simione]

put your stock exhaust back on and i guarantee that you will never hear the noise again