Plastic Spacers for use with the Exhaust Manifold??

I got all the parts I ordered for my broken exhaust studs. The parts catalog listed a spacer that is to go on the studs, and take up the difference in diameter between the stud and the large holes in the exhaust manifold that fits over the stud.

Thing is, the spacers that came are plastic, we'll maybe nylon, eitherway, I'd think anything short of metal would melt away if it was in contact with the exhaust manifold. I double checked the part number, its the correct number.

Anyone have a clue?

*Is this a plastic spacer just for installation, it melts away and does no damage during use?

*Is this some space age plastic that can stand up to the heat?

*Must it be a incorrect part, because there is no way a plastic part should be in contact with the exhaust manifold?

BTW, its 1995 2.5L I4.

In the 95 FSM, the spacers are mentioned as necessary ("use new spacers") but they do not describe them. Can you pry out whatever is left of your old spacers and see if you can figure out what they were made of?

No, the exhaust studs were snapped off at the head when I bought the vehicle. Nothing was left, no nuts, washers, spacers, just the end of the studs deep in the head.

Now that I think about this. The bolt hole in the exhaust manifold is probably way oversized to allow expansion & contraction without snapping off the stud or cracking the manifold. As the manifold expands and contracts, it can slide back and forth under the nut, and it doesn't hit the studs.

BUT, if the bolt holes in the manifold are oversized, you can tilt or get the manifold misaligned during install. The spacers may only be for install, to line up the manifold, they're suppossed to melt away after the install. That makes sense, I guess. Where does the melted plastic go?

I would hope they werent just supposed to melt away, as plastic will catch fire with high enough temperatures. Could be potentially dangerous that close to gasoline. Unless it is a more heat resistant plastic, with a higher melting temperature, that will not catch fire?

Well the area is sealed up. One side is the head/gasket, and the other is a nut and washer that totally cover the bolt hole in the exhaust manifold. So not much air going to get in there to support combustion.

The spacers look more like nylon, maybe they can resist high temps, but I don't think anything short of metal is going to withstand the temps of the exhaust manifold for long.

I honestly don't know, but I would fathom a guess and say they are used just as installation spacers for alignment, and are to be removed before all the bolts are tightened down.

Rass

esrasmu2001 said:

I honestly don't know, but I would fathom a guess and say they are used just as installation spacers for alignment, and are to be removed before all the bolts are tightened down.

Rass

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According to the manual, the spacers are meant to stay there. I think it would be a good idea to call a dealer and double-check that these are the right ones.

An alternative, I suppose, would be to take one of the spacers and stick it against a hot stove burner or something, and see what happens. If it doesn't melt, use it.

Odd thing here I just did my 96 not too long ago and I dont remember spacers at all..(I do see them on the part diagram now)

FWIW The Flange doesn't get quite so hot as other parts of the exaust -- it could be some high temp plastic.