Catalyctic Converter

Luck, apparently. They can fail anytime, though under 50k miles it's a warranty replacement. At 123k, I'm on my third cat; the OEM lasted 60k, its JR high-flow replacement managed 55k.

What is an indication its gone and is it testable?

In my case, the first failure had a buzz resonance, like a broken heatshield. The second failure had a nastier raspy resonance, with clanking when shaken.

Another failure mode is clogging.

I have that too. I figured it was a heat shield somewhere, but I haven't had time to hunt it down. I'm also on my original cat, on my '93 with 104k miles

-- Tonyrama Crystal White '93 A

Yeah, that sounds about right. But first, eliminate other possibilities: gravel in heat shields, broken weld or crack in header or downpipe heatshield, etc.

Larry, excellent info. I believe my heat shield was removed by the service station where I had it checked a year ago. The downpipe sounds interesting.

"tonyrama" wrote

I tried to track down a loose heatshield on my wife's '90 for months. Finally got so bad I pulled the cat and sure enough, loose bits and pieces made it sound like a baby's rattle when I shook it.

For Pat - this almost 14 year old cat had 97,000 miles on it.

My '90 with 134K miles is still sporting the original cat and has been subjected to the stringent annual testing demanded by the state of Texas.

Jerry Houston Texas '90B Red "Baby Car" Sees Rev Limiter Frequently....

interesting.

As I said, there's the luck factor. Some last longer than others, and I don't know of a thing you can do about it.

I strongly suspect it has to do with fuel selection, though I can't definitively tell you why. I *do* know that MMT-laden fuel is likely a cat-killer regardless of what Ethyl or SOPUS tells us.

That doesn't stop me from preferring MMT-based boosters in my JRSC-forced Miata.

Hah!

Dana