What kind of catalytic converter do I have?

hisenthlay · May 17, 2006

Hi, I'm new here as you can see. Just bought my GMC truck last week!!! It's a 98 Sierra 1500 SL, 4x4, auto, 5.0L V8, gas engine, reg cab, long bed. I got it checked out at Midas before I bought it, and one of the things that the guy said it needed was a new catalytic converter, because it "rattles", so he thinks it's "broken up inside". Now, I know nothing about auto repair (yet!), but I just did a search on the web, and found that if I have a pelletized converter, it SHOULD rattle, but if I have a monolithic converter, it should NOT rattle. So I want to know which kind I have. Also, I don't notice any rattling noise when I drive the truck--seems to drive fine.

The guy at Midas said the converter would be $200 to fix, and I just talked to a local mechanic with a good reputation who said it would be $379 + $68 for labor. Does either one of those prices sound fishy to you?

Thanks!

P.S. I noticed that the mechanic is taking some time off, but I was hoping that someone would have the answer. If I should be posting this on another board, please let me know.

Draenor · May 17, 2006

Sure its not a loose heat shield rattling? Are you getting a SES light or throwing any codes?

Mark_in_Tulsa · May 17, 2006

If the truck is under 80,000 miles then that cat is free, through the dealership.

hisenthlay · May 17, 2006

Thanks for the replies!

The truck is at 112k miles, so no warranty left on it, unfortunately. And I don't hear any rattling or any other funny noise when I drive, which is what made me wonder whether there was even anything wrong with it. I'm not getting any lights or codes. I just talked to a local mechanic, and he said that the pelletized cats are the older ones, and that the truck almost certainly has a monolithic one. He also said that I wouldn't necessarily hear any rattling.

My next question is--is there anything wrong with me buying a universal cat off of the internet, and having the mechanic install it? Has anyone tried this and had problems? Apparently the first Midas mechanic gave me a price for a universal one, the second guy priced a direct fit one, and I called a different, more local Midas shop that said he'd have to look at the truck before he was willing to put a universal one on it, and even then he wouldn't install one that he didn't supply. Both of the first two guys were willing to install one I bought. I was looking at getting the Eastern brand one for $93.76 off of this site: http://replacement.car-stuff.com/parts/car...showdc=true#top (it's about halfway down the page). Any comments on that? It'll save me anywhere from $100 to $175, but the mechanics won't give me a warranty on the job.

Thanks again!!

Draenor · May 17, 2006

If no codes are thrown, I would not replace it. The best way I check is to crawl underneath and bang on the cat with my hand. I had the

'monolithic" one break up on me. I just took off the muffler and blew out the chunks. As for the universal cats, I am looking my self. I guess I'm too lazy and cheap to spend the money, I just polute the air for the meantime.