I'm 99% sure that I have a cat failure on my 98 5.4L Expy. I am a college student so I'm looking for the cheapest route possible. I was thinking about getting two universals (one per side) instead of replacing the 4 OEM's and spending big $$ doing it. Are there any potential problems with this route that I might be overlooking??

Thanks,
James

 

The cheapest route possible is to first be 100% sure you have a cat failure. If you change the cats and it doesn't help, then you've wasted a lot of money and effort.

Why do you think all 4 of the cats need replacing?

 

i don't know missouri's emmision laws or if you guys have inspections there, but the cheapest solution is to remove the cat's and hollow them out with a long prybar or other skinny long piece of metal, or just replace them with pipe. tell the hippies to go hug a tree.

 

FIrstly, from everything I've read, you don't want to get any universal fit cat. I can't speak from experience but it seems there are a lot of failures due to the universal ones and the cheap OEM knockoffs. It seems the only realistic thing to do is to buy a good direct fit or original equipment cat.

Anyways...

I didn't realize the 1998 had 4 cats... I thought it had 2. Hm. Where are the other 2?

 

If you remove the cats or hollow out you will have a CEL due to the O2 sensors will detect inefficient catalyst.

 

Yes, mine has 4 cats. I don't know what year range did that, but mine is one of them. There are 2 cats inline on each side of the motor before it Y's into the muffler. My ride has 186k miles and I believe all the exhaust is original components from the factory. I have already ripped the heat shield off of the muffler due to it separating from the rear side of the muffler and was buzzing. Then I heard a new rattle and when I got underneath the truck it was coming from the interior of the cat on the rear passenger side. I also noticed a sheared off stud on one of the headers. I'm thinking about just replacing the whole thing, headers all the way back to the tailpipe. It's gonna be expensive regardless, but it needs to be done! The OEM replacements I have seen were roughly $300 per side give or take. And that was just for the cats! I just put new pads and rotors all the way around and e-brakes, so the wallet is still recovering from that!

 

The universal cat that I was looking at was from Magnaflow at roughly $80 a piece.

 

Hmm. I'm going to have to go look under my truck and see what I see.

As far as the cat brand goes, I wish I coiuld find the site I was reading that was talking about the problems with universal fits vs direct fits. All I remember is that there was a lot of people mentioning that the universal fits wear out fast and need to be replaced a lot sooner.

Hmm. Obviously your luck will vary.

 

Cats 'usually' don't go bad. Something else causes them to go bed, so it is important to figure out exactly what caused your cats to go bad, otherwise its a good probability your new cats won't last very long.

 

i forgot to mention if you do replace you cats, take the old ones to a junkyard or metal recycler. they have platinum in them and you can get any where from 30 to 150 bucks a piece for them. it will help offset the cost of the new ones

 

Wierd. I have the same truck as you do. '98 Expy, 5.4 and I only have 2 cats that I can tell. Pipes out of the manifold, cat on left and right pipe, drivers side bends around and connects with passender side and they go into the muffler.

I just have to ask to be sure but you're not talking about O2 sensors are you?

 

Did the 1998 Expy originally come with 4 cats? I'm the 3rd owner so I don't know if they had been replaced in the past. I bought the truck with about 98k on it. Have 133k now.

 

I think they do come from the factory with 4, but I don't know for sure. Some of the OEM replacements that I've seen online have them setup for the driver side and passenger side with 2 cats each from the manifold to just past the Y connection. Which is identical to the way mine is setup. My folks bought it in 2000 and I bought it bought it from them a couple of years ago. No exhaust work has been done since 2000 that I know of. Since the truck was only 2 years old we got it, I am willing to bet that it came from the factory with 4, I would rather only see 2, but I didn't make that design decision. I do a little bit of towing with mine, so redoing the exhaust has always been on my list of things to do, but it looks like I'm gonna get to it sooner than planned.

 

My 1999 Expedition has 4 cats also. Does anyone think between those and the stock headers, there maybe be a lot of pressure that when released could give a decent power boost?

 

Hmm.. now I wonder if my exhaust was redone at some point. I'm not exactly sure how to tell unless I happen to see some sort of name on the parts but I've never noticed one.