T-Smac

I bought my first s2000 (a 2001) last year and a couple months later, the catalyst inside the catalytic converter broke apart and made a god awful rattling noise. I bought a used cat replaced it, no big deal. Sold the car and now I have a 2004 s2000. Same thing happened. I was planning on upgrading the cat eventually, but not yet. Guess I have to.

Is this just coincidence? I'm not smacking my cat on the ground, bottoming out, or anything like that. Car is running clean. Bad luck I guess?

EDIT: Added a question in my most recent post. Will they give me warranty trouble because of my aftermarket intake/exhaust?

BowlofRice

I think cat is covered for 8 years. Take it in and they will replace it for free.

Mine has been replaced as well. Just happens.

slalom44

That's very strange. Unlike most cars, the cat on an S2000 is not ceramic. It's called a metal monolith. It's a corrogated sheet of high alloy stainless (18SR or equivalent)rolled up and sandwiched inside the clamshell housing with a ceramic fiber mat "blanket" surrounding the metal monolith substrate. The fiber mat holds the substrate in place.

Ceramic substrates can eventually get jarred enough for them to come loose, but metal substrate cats can take significantly more abuse. I doubt that your problem was caused by excessive vibration.

It is more likely that you had engine management problems. If you were running extremely rich you'd be dumping a great deal of fuel into the cat. The cat will catalyze any unburnt fuel with any remaining oxygen in the exhaust, giving you extremely high temps. This would melt your substrate, causing it to come loose and rattle.

I have seen this happen countless times on other cars. In a former life I used to help diagnose exhaust system failures. If your cat truly "broke apart", then you had an aftermarket ceramic cat that wasn't designed to take the abuse (and the heat) of a stock cat.

davidc1

This is actually a not uncommon problem in our cars. Search around and you will find many threads and scores of cars with the problem. If it's got less than 8ys and 80000 mi on it it'll be covered. If you let it go to long, it will chop off the nose of the O2 sensor as well. That's a $200+ item at the dealer, less than $50 for a direct replacement on the aftermarket.

cdelena

Nah, this is not unusual on the S2000. It is a poor design and if you run it hard and bounce the car around a little the element comes lose and damages the O2 sensor. I've had it on two cats, a 2000 and a 2003 and if you look around on the web you will see dozens more failures.

slalom44

Coming loose, yes. Breaking apart, no. Maybe the OP was using the wrong terms.

davidc1

semantics. After it comes loose, if you let it bounce around a long time, it'll break apart.

Saki GT

I replaced the cat and O2 (under warranty) earlier this year on my 2004. Substrate broke loose and was rattling about, which decapitated the O2 sensor.

Take it into the dealer and they will pull the O2 and reaffirm that the cat is bad. Just make sure they order the new O2 sensor at the same time or it will be two trips to get it fixed.

T-Smac

I suppose since it is warrantied I'll get the free cat. It could be "loose" inside of there and not "broken apart." Doesn't so much matter does it? It's junk either way. It's OEM not aftermarket.

Like I said, my car is running clean.

T-Smac

I have an appointment for them to verify it's the cat tomorrow. Guess they can't take my word for it. I have an aftermarket intake and exhaust on it right now. Are they gonna give me warranty trouble with those?