Rattling noise coming from cat

[RyanGiorgio]

About a week ago I noticed that when my car is idleing at about 1500 RPMs when I first start it up, the catalytic converter makes a moderately loud vibrating noise. The car also does it around 3000 RPM's. Anyone know what the problem is? I think its either clogged or loose, but I have no idea. Thanks in advance.

[dlinvill]

Are you sure it's internal noise? The heatshield are just screwed on and could easily get loose enough to rattle. Also check where the exhaust bolts onto the tranny hanger. It doesn't seem like anything would get stuck in your exhaust near the cat without passing through the turbo (and making a big mess). The cat can break up but that would be very rare.

[dlinvill]

Sorry I was thinking WRX, i guess in the RS you might have something make it out the engine and get stuck. You could always unbolt that section of the exhaust and see if anything comes out.

[ragnarok720]

Ive heard of cats breaking up, rare but it does happen. Did you try to gut the cats by chance ever? Sometimes people dont get everything out and it rattles around but im not sure if it will make the noise you discribe. Might want to check your exhaust hangers and the bolts alongth cats as well as maybe checking the gaskets. Loose exhaust makes a lot of noise as ive found out.

[Diesel2NR]

yeah. I'd check all the hangers and everything. I've had a rattle that was somewhat like you're describing when I had my dakota. I went under it and tightened all of the bolts and everything and it was gone. If that doesn't help, it might be time to get a new Cat. (Note: by national law, these are supposed to be garenteed for 80,000 miles I believe)

[freakray]

There is a heat shield on the cat, have it checked or check it.
We had the same happen on our '01 Forester.

[RyanGiorgio]

Originally Posted by freakray

There is a heat shield on the cat, have it checked or check it.
We had the same happen on our '01 Forester.

I took it in, and it was indeed the heat shield. He just removed it. 30 dollars! I could've done it myself if I knew in advance.

[freakray]

Dang!

Calkins Subaru charged us $7 to re-fix the heat shield correctly.

It's amazing how some dealerships are in it for the money while others are customer oriented.

[SabreKhan]

Customer-oriented dealerships? I thought only Saturn had those... I've never been to a non-Saturn dealership that was really both friendly and helpful at the same time (a couple that were one or the other... but most were neither). The Mitsubishi dealership I went to last week (needed a part for my friend's GTO) acted like they couldn't even be bothered to acknowledge my presence, much less do their job. I haven't had too much experience with Subaru service, though, so I guess I shouldn't start talking yet.