FinallyAC5

Hello,
Like a lot of people, I'm new to the forum and I have a question/concern!
When I take my foot off the throttle I can hear a rattling sound, almost as if there was a hose clamp or something like that lightly tapping on a metal pipe. It definitely sounds like metal on metal. I popped the hood but couldn't hear it from there, but from the sides or underneath the rear of the car I can hear it very clearly. It does it whether I'm driving or sitting still and just rev it. I think I can hear it pretty faintly when the car is idling as well.

I put the car in the air and shot a video, although it's sort of difficult to hear the rattle because the mic on the phone isn't that great and there is a loud exhaust right by it. I also shot a video earlier this morning after the Borla exhaust was installed, you can pretty clearly hear it in that video too.




Any ideas or thoughts would be great, thanks!

Rob 02

I'm just guessing. The middle exhaust mount. The one with the springs.
They are known to brake.

FinallyAC5

If I had to guess I'd say it's coming from that area. I looked it up on Google and I'm clearly not the only person that's had these kind of problems. I'll look into it further, but that seems like a plausible cause for the problem. Thanks Rob!

grantv

I feel the mounts are kind of overdone, making front or rear redundant. But yes, the spring mounts are likely the cause of the sound. The other common sound cause is the H pipe jingle.

FinallyAC5

Silly newbie question - how would you go about checking this? Jack the car up from the front and climb under the sides or front? Jack from the sides? Back? It may be sad or pathetic but I'm not only new to the 'Vettes but I'm also new to this kind of stuff, most of my other maintenance work is under the hood or simple brake jobs.

Also, would it be a good idea to pick up (or make) some ramps? I am considering a QuickJack lift because of price and size, but I would like to expend all avenues before pulling the trigger on that.

Rob 02

Whole car up on jack-stands. The problem is in front of the rear axles. You can make ramps if you want.

Silverwolf_pup

I have the same problem, I have Corsa Xtreme on mine, when I let off of the gas it has rattling or jingling sound, where is the spring mounts located?

Rob 02

At the front of the transmission.

Rob 02

FinallyAC5

Ok, now I have to go investigate, that's much closer to the rear of the car than I was thinking, it's been a busy evening and this is the first chance I've had to go take a long look.

FinallyAC5

After jacking up the rear of the car and using a flashlight to look, I can see that the mounts and bolts look pretty rusty as do the welds on the exhaust hangers. There is also the spring attached between the two springs, which tells me this type of thing has happened before. Is there a permanent fix to this? I'm having new wheels and tires mounted tomorrow/Saturday, is this the kind of thing that I can ask them to take a look at, or would I be throwing money out the window?

grantv

After I installed my headers I had an exhaust shop install some "standard" rubber isolated hangers. The front is only suspended from the headers.

photonhunter

My girlfriend used to freak out when I first got my 'vette because she could hear this metallic rattle every so often. Her level of despair was such that she thought the engine was about to explode.
I kept telling her it was just an ill-fitting center cap on a wheel but it took months before she stopped complaining about it.
My point (and I do have one <g>) is that your rattle may be extraneous to your exhaust.
Please post what was causing it when you find out the answer.
Good luck,

dan k.

FinallyAC5

I'll have to look into that, I was reading more about it online and found another post (apparently this is pretty common) that said it was a passenger side heat shield on the firewall that was rattling.

old stingray

You have one sweet sounding C5.

FinallyAC5

Thank ya!

So I had the wheels and tires mounted today and told the shop about the rattle. They had me come in and show them the rattle since they weren't sure about what I was referring to. They put it on the lift with a guy inside of it who revved it up while two of us walked underneath the car and listened. We listened very carefully to the area with the springs and it didn't seem to be making a sound.

One guy used a screwdriver held up to his ear to listen for vibrations and they were very apparent in the H pipe, but nowhere else. He thinks it's a faulty weld where slag is inside the H pipe bouncing around causing the sound. That sounds plausible, but I'm going to see if I can test that hypothesis by shaking the pipe while it's on the ground and the car is off. The idea of throwing parts at it is both expensive but fun, and something that I'd rather not do for a little bit. Any more thoughts/ideas?

Rob 02

Some people say that the H pipe sounds like there is change jingling inside of it.

Here is what one looks like inside.


There very well could be a piece of metal in it!

FinallyAC5

I laid on the ground this morning and used the handle of a hammer to lightly tap the exhaust while the car was turned off, I can definitely hear a jingling sound around the H pipe, but it's a little bit farther back, towards the rear of the car. I found the Borla 60087 X pipe on Amazon for $240 so I ordered that. It looks like a pretty straightforward install, just get the car in the air, use a sawzall to cut off the stock pipe/unbolt the catback then slip on the new one and clamp/bolt it up. Hopefully that solves the problem.

Rob 02

I wonder if there was broken cat material in there. I guess you will find out soon.

Silverwolf_pup

With my Corsa it makes a rattling sound, but the sound is coming out of the end of the pipes, to me it sounds like it is the tone and it sounds awful, some people told me it could be a broken baffle inside my Corsa, if I change the stock h pipe with a Corsa x pipe would that fix the tone?