I recently bought an '88 crossover pipe from the Fiero store and am having some problems getting it to seal up.

I have two Fel-Pro 60538 donut gaskets to go between the stock exhaust manifolds and the crossover pipe. They just slide over the flange and are fairly loose. Advance Auto shows the same PN. Is there a different part that fits right or can I use some high temp RTV to seal it up?


I also got a crossover to cat gasket, and it looks like it's the same diameter but with no sleeve inside. The bag doesn't have a brand but shows 521803 as the part number. I haven't tried to install it in case I need to bring it back although i think it will fit because the cat connection is bigger.

It looks like the opposite of this problem, the tin metal sleeve is too big.
https://www.fiero.nl/forum/Forum2/HTML/094886.html
Autozone has the 60650 part but I would have to order it and there are no returns on it. I want to know if it fits before I shell out $20 for two more gaskets.

Just to let you know...there are 2 listed cross-over to cat pipe donuts for V6 fieros from 85-88.

The is one for 85-86, and another from 87-88. I don't know if there is a major difference in size, but there is 2 different part #s as that goes for Fel-Pro...

I don't know if GM still has them available. I bought one from The fiero store for 87-88 V6 and the part was a fel-pro brand...going to have to see until I install it.
The one on my car right now is a GM donut gasket.

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fierogt28

88 GT, loaded, 5-speed

So there are no gaskets from the y-pipe to the manifold?


I'm pretty sure the one i got for the cat is going to fit

There are no gaskets between the manifolds and the Y pipe the tulip flare accepts the rounded manifold ends ..
sometimes you have to cut down the manifold flanges,,( I square them) for a good tight fit ,,just check for major flaws that would prevent proper fit

High Temp RTV on an exhaust pipe would burn on your first drive.

quote Originally posted by fierogt28: Just to let you know...there are 2 listed cross-over to cat pipe donuts for V6 fieros from 85-88. The is one for 85-86, and another from 87-88. I don't know if there is a major difference in size, but there is 2 different part #s as that goes for Fel-Pro... I don't know if GM still has them available. I bought one from The fiero store for 87-88 V6 and the part was a fel-pro brand...going to have to see until I install it. The one on my car right now is a GM donut gasket.

The V6 88s have their own exhaust design. The 87 has the same exhaust design as the 85 and 86... I don't believe that the Fiero Store is correct in dividing the production that way...

I just looked it up on RockAuto as well... how could the 87 with the exact same crossover pipe and cat pipe as an 85/86 use the same flange gasket as the redesigned 88 exhaust???

[This message has been edited by carbon (edited 03-04-2010).]

quote Originally posted by phonedawgz: High Temp RTV on an exhaust pipe would burn on your first drive.

Absolutely not!!!!!!! high temp rtv will be fine. I used an even bead about 1/4" wide in the cup on the y pipe ends to seal to the sprint headers, and for the donut at the down pipe, I used it on both sides of the donut . Regular orange exhaust rtv will not burn even if it is sitting right in the exhaust port. the stuff is incredible how much heat it will take. it is excellant for sealinng the exhaust manifolds to head, use a paper thin coat on both sides of the gasket, and if you have the rear heat shield on yours, you are actually making a gasket as there is none on one of the mounting surfaces. in that case the gasket goes to the exhaust log, then the shield, then the head.

I've used high temp rtv as long as it has been out and never had an issue with it burning up, even on my cat flanges gaskets. the current ultra-copper high temp is the best of the crop tho, as you cna dissasemble, and re-use your gaskets multiple times with some cleaning.

I have a new tube of the permatex ultra copper stuff, i'm going to give that a shot in the next few days. It's only going to need a little bit.


I thought the y-pipe ends would deform a little and form a seal on the manifold, but the tubing is too hard.

I just installed one about a month ago on an '88 V6 and got the donut gasket from NAPA, part number 521803-001 for CDN$17.00.

I also bought one from Advance Auto. I do not have the p/n, but the part was very inexpensive; I think $11-$12... BTW, I am talking about the y-pipe to down pipe (to cat) graphite gasket... The manifolds to y-pipe have no gaskets, as mentioned above...

I just thought I'd post an update

Both of the donuts fit on the catalytic converter connection. No problem there. I have an extra one laying around now
I had no problem with the trunk side connection, although I did put a dab of exhaust sealant on the mating surfaces. Nice solid connection, no leaks.

The backside connection basically doesn't fit. It's off by about half an inch so even when I do manage to get the flanges lined up, only about half of the flares end up touching each other. I'm perpetually left with a sizeable gap on one side or the other. I've tried installing that side first, and then the cat and 'front', but then those two aren't even close. I tried to bolt it to a board, stand on the board, and gently pull on the other end to try and get it to bend a little but no luck. It's good that it didn't bend because it would probably crack in the same spot the original one was. I'm tempted to go redneck and dump some high temp rtv on it, trim a thin band of steel to wrap over the gap, and put a big ol hose clamp on it.

Beyond the fact that it doesn't fit right, I haven't exactly been pleased with this y-pipe. The overall quality isn't quite what I expected for $220. There is a some welding slag trapped under the heat coating. I realize that is a hard thing to control, but this is like dripped down the length of the pipe and not by the joints. The welds are very nice and smooth, however. It's rusting all over. Worst of all, it's not shiny like the picture on the website. I would send it back, but I bought it a while back and I doubt the Fiero Store would take a return on something like this anyways.

edit: typos

[This message has been edited by mechcd (edited 03-17-2010).]