FirstGen7

I just discovered this today...

When I rev the engine up to about 3500 or so and let the tach come down, at the lower rpm's I hear a little metal clinky sound...

Almost like a metal washer clanking around in a vibrating can...

I'm thinking it might be a blown cat? Sounds like it's coming from under the car...but it's kinda hard to tell.

It's not consistent either. Sometimes it happens, other times you can't hear anything...but I noticed it right in the middle of a rev, so I'm thinking something broke loose.

Any thoughts?

Blake

You need to be more specific. Is this happening in neutral, just free-revving, or in gear, on the road? Is there any vibration related to the noise? You said it happens as the RPMs go down, but then you say you heard it in the "middle of a rev". Which is it? Can you have a friend outside the car listen while you rev the motor?

The first thing I'd do is jack the car up and look for debri in the driveline (like piece of sting or wire), and check the exhaust heat shielding, which can rattle quite badly when loose. Is the tranny bell housing completely buttoned up? There are clutch inspection holes and such that usually have a plate or rubber plug. If one is missing, there is the possibility of a pebble or something getting in there and rattling around -- very dangerous, however unlikely. Lots of possibilities...

FirstGen7

Alright, I'll try to describe this in more detail...

I noticed it in nuetral, free revving. I haven't tried it in gear as of yet, though I will asap, and give you results.

In the middle of one of the revs from 3500, is when I FIRST heard it. That's when I thought something popped loose.

From then on I only heard it was coming down from a rev.

I've not noticed any added vibration in relation to the noise.

I'll be checking the clutch inspection holes...hopefully it isn't that.

I didn't figure the possibility of the exhaust heat shielding, it may actually be that. Once again, I'll check and report back asap.

Blake

Don't bother trying it in gear, since you've already eliminated a bunch of possibilities right there. Was this in nuetral with the clutch out or in? Have you checked your belts and accessories? Again, have someone outside the car listen for you, including under the hood. Since it's not in the driveline (other than the bellhousing possibility), all the likely culprits are in the engine bay. Hunting down noises is like detective work, as you solve the case by eliminating suspects (deduction). Try removing accessory belts one by one, except the water pump.

FirstGen7

So it couldn't be anything to do with the exhaust?

Gah...didn't want it to be in the engine bay, lol

Blake

Well, sure, that's a possibility too, but any rattling sound would likely be accompanied by a vibration...even a "normal" one, presuming something came loose. I suppose you should also check out your engine mounts, as excess movement would perhaps cause contact between the exhaust or shielding and the body.

I once had a hell of a time finding a similar rattle on my 2nd gen, though it only happened when driving. It turned out to be the lower main cat heat shield. Like I said, work by deduction. Check the easy/obvious stuff first and then move on the the rest one by one, methodically. It's a PITA, but you will feel better knowing what it is and eliminating the problem.

FirstGen7

Yeah, these little random things are hard to pinpoint...

I'm just nervous about driving it, I don't want to put extra stress on anything if I don't have to.

Which is why, as soon as it stops raining, I'll be absolutely violating my 7 to find out what the hell this little annoying rattle is, lol

*puts on latex glove* *snap!*

"Well hello there, RX...turn your wheel and cough please?"

FirstGen7

Well, Blake...I tried it in first, I tried it in nuetral, I tried it in nuetral with the clutch, I tried it in second...

It does it in every one.

I really think it sounds like something's rattling around inside the cat...

I mean, it sounds like there's something either in the piping of my exhaust or in the cat rattling around, ie a washer or bulb or something...has anyone else experienced something similar involving their cat? If it IS something with the cat...you think it'd really hurt to drive it around for a couple more days until I can replace it?

It probably wouldn't hurt to get a new one in there anyway...lol

I can't figure what it'd be in my engine bay...I mean, if it was a loose shield or something, it'd sound more open...but this sounds like it's inside of something.

I drove it around and didn't notice anything different...

Grrrr