Metallic Flutter Sound!!!
 

I have recently started to hear a sort of metallic fluttering sound coming from the rear right hand side of the car. It is mainly apparent when I'm in 1st thro 3rd gears, between 1000 - 3000rpm. Although it now seems to do it when the car is stationary and you just rev it. It is really apparent when the sound can bounce off a wall upon acceleration. I have read about this in the past on one forum but an in depth search has come up blank. I think it is something to do with the exhaust. Can anyone help?...........Oh it's a 2001 Boxster S with 33,000 miles.

Thanks :confused:

I have exactly the same problem on my newly purchased 2001 S(60,000mi). I brought it in for a state inspection and they did a quick check of the heat shields but couldn't pinpoint where the rattle originated. Now I have an appointment for next Thurs. Will update the result then.

Thanks dj1. My nearest Porsche dealership is 3 hours away, so therefore would appreciate any help diagnosing the problem.

I have the same on my -02 boxster s.. its the only boxster I've heard and thought this is the way they sound.. no?

Damaged cats?
Loose heat sheild?
Motor Mounts??

I am thinking damaged cats but surely they don't go after 30K and/or 6 years!!!

It's probably just a loose heat shield rattling a bit. Get under the car and check it out.

I have been under the car and can't find any loose heat shields, or any thing else loose for that matter. I only happens when the car is hot, after a sprightly drive. I would have thought loose heats shields would be constantly loose!!

Mmmm...are you sure it's not just the cats "popping" when they are hot? They will make metallic noises after you drive the car and let it idle or sit which is completely normal. If you are familiar with that noise and that is not it, what does it sound like exactly?

ok, just talked to my mechanic. both flutter and rattle are from cats. the explanation was a bit confusing(for a novice like me) but there's a crack on the cat where it connects to the manifold. because it passed emissions he says it's a tough sell to have porsche replace it, but a new one would get rid of the rattle. The other one he's taken off but couldn't reproduce the noise, so he's still checking it out. we talked about welding, which he says he's done in the past, but has found it to be relatively temporary as the high frequency vibration tends to crack them sooner than later. Bottom line - i know and trust these guys, so i'll probably go with their suggestions when they call me back with a quote. will keep you updated. dj

Thanks dj1, yes please keep me updated. Out of interest, iIs it a Porsche garage that has done your trouble shooting or just a Muffler Shop?? Will a general muffler shop have the experience to help with the diagnosis? I have a relatively local one as opposed to a Porsche garage which is miles away!!!

it's an independent that works only on porsche,audi,&bmw's. I did stop by a muffler place, and the mechanic happened to have had a number of years experience with porsches,and while he pointed out a few possibilities(as far as tack welding) he felt it's simply too specialized to not have a porsche guy deal with it (especially since you have a longer warranty on the cats).

Any news dj1??

It's in the shop. They ordered a new pass side forward cat - due in Mon - part $975, labor $230. Hope that'll be the end of that! Will let you know. dj1

Finally got it home. No more rattle. So apparently it all came from the forward cat. Wish it had just been a heat shield, but not my luck. I am glad I had a Porsche guy deal with it before I took everything apart piece by piece. Good luck Leathers.