randomwalk101

What are some of the causes for catalytic converter rattle/broken (core)?
My car is still under warranty, 27K miles or so...Everytime I start up the car, there is a loud rattling under the car. I crawled down there, tapping around and sure enough, the rattle is right at the cat. It's not the head shield (they on tight). I tried to tap on the cat and there is like a core in there broken and moving around making the sound.

Anyways, took it into the dealer and it was the diagnosis and the new cat is on order (they don' t stock it).

Anyone has this problem before? No, I didn't hit anything (otherwise there will be mark/dent etc..but I know I didn't hit anything).

NJ Aegean 03

I actually have the same exact noise that you do. At first, I thought it might have been a leak (gasket) somewhere, as the sound only happens at idle. If anything, it would probably be cheaper to order aftermarket cats for the car and have them put on. Just out of curiosity, how much was the cat-con that you ordered?

NYZGREATST

deyum thats def weird

randomwalk101

i didn't order...Acura did..the car is under warranty so they should fix it free. anyways, its like $1000 or something...expensive!!!

mclarenf3387

The Catalytic Converter is covered under a 8yr/80k mile Federaly Mandated Warrenty Not to mention hes under the factory warrenty period so it would be worthless to go aftermarket.

And its strange that the core broke with so few miles on it, but it happens. I've seen cars blow the core straight out of brand new cats, granted these were boosted high power cars

fla-tls

Sounds like a mfg. defect (a rare one).

ResidualFreedom

Duh...

That what a cat sounds like when it goes... the honey comb-like core breaks and then there no fixin it... it's gone! The good thing is the cat is a safty/emmission item and it is covered by a government standard warranty. This allows all cat's to be warrantied for 5 years or 100 miles (pretty sure that's the numbers... I;m trying to convert from Canadian, and remember the wording I heard from the dealer. Oh, and yeah they are over a grand to buy..

Lawaia

Chances that the cat is defective is very very slim. The most common cause towards cat failure is the car running too rich. The unburned fuel contacts the heated catalyst in the converter causing it to ignite, thus overheating and melting the internals. You may want to check the O2 sensors as a failed sensor would cause the engine to run rich.

03CoupeV6

Does it rattle constantly at idle?

ResidualFreedom

If you hit the cat with a hammer and it rattles, like something is loose inside the cat bouncing around, then the cat is GONE... it doesn't really matter how it happened, people speculating and guessing why won't fiix it... Fact is, some cats just go, obviously if you are running double the HP through a stock cat it would go quicker, but even under normal conditions cats just go...

I had this happen on my S-10-ss, and just two weeks ago at my mechanics, I saw a VW bug up on the hoist, the owner, not to stereotype, was a really hot, ditsy, blond chicky, she didn't know what was wrong with her car, but she gave him a brief description of the car's symptoms.

My mechanic pulled the cat cover off, grabbed a hammer, and hit the cat. I heard an obvious rattle.. "Yep, your cat is gone, let-me call VW and check the warranty on this one.." . He called VW gave them the VIN number and and set up and appointment to get the cat swapped with a new one. The mechanic spent less time working on this bug than I am spending writing about it.


It's as simple as that, if the cat is rattling and it's not the cover, then it's gone. The cat is made up of a honey comb-like structure inside. If that honey comb breaks, it breaks, there's no way to fix it.. But like I said above, and Mclarenf3387 stated much clearer than I did, the cat is covered by a federal warranty, and it is most likely covered under warranty..

If not, it will be very expensive to get a new cat(+$1000) from Acura, so I would suggest a low milage cat from a junk yard.

randomwalk101

Thanks for the suggestion but it is against Federal law to buy/sell used catalytic converter.

ResidualFreedom

didn't know that... there's always an aftermarket high fow cat. they run from 300up, and pass emmission standards.

TunedTL

Are you saying all used cats (even if someone total a new car driving out of dealer's lot) get trashed? Got to double check junk yard for that...

Lawaia

Check out Magnaflow Car-Sounds Cats. You can get them for less than $150.

TunedTL

Is Magnaflow a bolt on for TL?

UnsanePyro

Did you guys who had cats go out get any sort of rattle other than at idle or at WOT?

I think mine is going, it makes a rattle, I'm not quite sure how to describe it, under acceleration and if I quickly let off the gas.

It has not made a noise at idle until the last few days, and at idle it is very quiet.

I had a mechanic say it was probably the cat, but he was not sure because he could not get it to reproduce the noise at the time, but now, I can almost all of the time.

I had an O2 sensor go out when I bought the car (15,000 miles ago) which, iirc, causes the car to run rich?