noisy cats

[hjnc]

I have been plagued by noises coming from the rear - rattling, snare drum-like - two dealers have claimed its the heat shields and "fixed" the problem :P . Dealers couldn't make the noise go away. I removed the heat shields myself and the noise stayed. Finally, I tapped around with a rubber mallet and found the source of the noise: the catalytic converters. Something inside is loose. Does anybody have experience with this? I'm afraid if I go back to the dealer, they may start up with the heat shield thing again - I don't want to waste my time.

[Loren]

I've heard of a number of broken welds in mufflers but not the cats. Not to say the cats can't have a broken weld too...

[911h20]

My car has developed a rattle on the driver side exhaust. I checked the tip and it was fine. What did you finally discover as the problem.

[ron in sc]

Here's a photo of a cat with a hairline crack in the weld bead. It is off of a MB ML 320. The cat is not damaged, that is the inside of same has not come apart, there is no rattling. It's going to be TIG welded tomorrow and I'll reinstall it then. I'm sure that same can be done on a Porsche cat assuming the contents of the cat are not broken.

[Hotbasco]

My 2000 C2 has this "rattle" at cold start up at the passenger rear. Have not searched real hard for it since it goes away when system gains heat. First minute or two.

[Stefan]

I believe the Cats have a 10-year warrantee. You may want to have your dealer take a look at it (and fix it for free if that's the problem).

[REDLINE WINS]

I have been plagued by noises coming from the rear - rattling, snare drum-like - two dealers have claimed its the heat shields and "fixed" the problem :P . Dealers couldn't make the noise go away. I removed the heat shields myself and the noise stayed. Finally, I tapped around with a rubber mallet and found the source of the noise: the catalytic converters. Something inside is loose. Does anybody have experience with this? I'm afraid if I go back to the dealer, they may start up with the heat shield thing again - I don't want to waste my time.

<{POST_SNAPBACK}>

noise is from the mufflers...current tech bullentin on this issue.

[josefiii]

:cursing: This has been making me upset for weeks... the same rattling in my cat (yes, one of them-Passenger Side), and a check engine light, has the 996 going in for service... a day or two before any of this started-- the car was at the dealership, I don't know how coincidental this was, but I had them do an oil change and replace the airbox filter... how realistic is it to question that they knocked off a vaccum hose, or broke the O2 sensor or worse....?

The funny party is that the act like--hey its no big deal... the car had been drinking fuel.. and I mean drinking

You folks note the noise, but were you also getting a CEL?

[Danyol]

Josefiii,

What did your issue turn out to be? Coincidentally I have an exhaust rattle (nothing external) and had a check engine light PO430 "CAT system below threshold"

[Daiji]

I have been plagued by noises coming from the rear - rattling, snare drum-like - two dealers have claimed its the heat shields and "fixed" the problem :P . Dealers couldn't make the noise go away. I removed the heat shields myself and the noise stayed. Finally, I tapped around with a rubber mallet and found the source of the noise: the catalytic converters. Something inside is loose. Does anybody have experience with this? I'm afraid if I go back to the dealer, they may start up with the heat shield thing again - I don't want to waste my time.

3 months ago, my local dealer noticed a rattle in my Catalytic Converter and informed me that it would need to be replaced at an exorbitant cost. I searched around on the internet to find a used or replacement converter. What I found instead was a EPA Emissions Warranty that states that for cars 1995 and newer cats are under a emissions warranty of 8 years or 80,000 miles. I called my local dealer and he said he would look into it and get back to me. A few days later he called and said to bring my car in for a cat replacement at no cost to me. Sweet Deal

[Izzy]

I just had the same problem. A rattle sound from the mufflers after a day of DE at VIR. When I inspected by tapping with a rubber mallet, found that the cat sounded like it had loose marbles inside of it. Called our local dealer and he has replaced a few since the DE season started, apparently the vibration of running over the "gators" or rumble strips as you track out can loosen the welds. Warranty work.

[Danyol]

Guys,

Mine turned out to be a bad CAT on bank 2, it was noisy and the internal parts had come loose plugging the flow. I've gained back a whole bunch of power at the top end, and I have a beautiful sound back from the exhaust.

Incidentally it was a battle with the dealer to get it covered under EPA mandate warranty (8yrs, 75k). The excuse was my car is "modified", It has GHL headers and exhaust. If it had a Porsche sport exhaust they said it would be no problem. :unsure:

My local shop went to bat for me (Foreign Affairs, Pompano Beach FL) told them it's baloney, went to PCNA. Bottom line, they paid.