RamVA

Hey all -

I have an '01 C2, and the car is in the shop getting it's second new cat in less than a year (opposite side). It has about 50k on it, had maybe 46k when the other side was done last fall.

I asked my service advisor if this was common, and he said no. Should I be worried about any more significant upstream problems which may be causing this issue?

The car has no power mods, no changes to intake or exhaust. It's seen perhaps 15 track days since I got it two years ago.

TIA.

djantlive

what makes cats go bad other than poor gas? i'd think there is something worth looking into.

RamVA

I've had a few bad cats in other cars, and it was oil-burning (Miata) or coolant in the exhuast (S4). This 996 tends to burn some oil in track use (you can see it in the exhaust), but nowhere near the level my Miata did in normal driving.

Holger B

Check into the warranty on those, by law the emissions systems may have longer warranties than the rest of the car. I bet you can stick PCNA with the bill for those.

For example, my owner's manual says CA cars emission-related parts are warranteed for 7yr/70k miles.

RamVA

The emissions warranty for my model year and region is 8/80, and the direct issue is being taken care of - the cat itself is not my concern. I'm worried there's some root cause for the cat issues that is more serious and more expensive. I'm wondering if there's a common 996 issue that might be driving it. If not, so be it, I won't get too worked up about it.

Holger B

Gotcha.

I think it's rare for the cats to go bad so early, but I understand your concern since you've experienced it multiple times now. Not sure what the cause is, but I'd want to know also. Hope you figure it out.

Tim Wasmer

Only be worried if this was your mechanic

TD in DC

The Cats can go bad if unburnt fuel makes it to the cat, where the heat ignites it within the cat. When this happens, you can blow out the ceramic internals of the cat, which makes it rattle unless you are on the gas. One potential cause can be fouled plugs. Have you tuned your car up lately?

TD

RamVA

Thanks, good point. The car is running well and there's no other evidence of a rich condition, but I don't think the plugs have been touched. Appreciate the help.

Riad

Awesome!

Should I be worried about cats? These guys are worried too...

99firehawk

they tend to fail on tracked cars, they are covered for 8years/80k miles but i wouldnt worry anymore, they arent covered once you say "I have tracked the car 15 times.................

RamVA

Why not?

BruceP

Running rich over an extended period of time can cook your catalysts. Possible reasons for running rich (without running rich enough to get a CEL): Running exclusively on regular gasoline, driving exclusively in stop and go city traffic, too many short trips so that the cats don't reach operating temperature, using ethanol enhanced gasolines routinely (although the octane rating of ethanol enhanced premiums is higher, the engine doesn't see it that way and many cars ECUs will respond to ethanol combustion as if it was pre-detonation).