witch plenum gasket

[joeshiff]

got a 99 4.0 ohv non egr. have a cracked plenum. the new one has the o rings installed in the bottom. napa showes a 1/4 inch gasket for the bottom. is this fords fix so the plenum does not sit directly on the engine and crack again? should i use it or just put it back the way it was.

 

[cr_the_machinist]

Are you talking in regards to the gasket between the lower intake and the fuel rail?

 

[joeshiff]

no, the plastic air plenum to the intake manifold. the plastic plenum has o rings at the mating surface. i installed it and it leaks. should i use silicone or the thick gasket

 

[982WDRanger]

On 98+ OHV the lower intake uses same style lower gasket that mounts to the valley in the block. But where the Fuel manifold and lower meet there is a thick gasket between them. its a fuel manifold gasket, fel-pro makes one. Use that one in between the lower and the fuel rail.

 

[holyford86]

On 98+ OHV the lower intake uses same style lower gasket that mounts to the valley in the block. But where the Fuel manifold and lower meet there is a thick gasket between them. its a fuel manifold gasket, fel-pro makes one. Use that one in between the lower and the fuel rail.

You post stuff?

If you are using the proper thick lower gasket and everything is installed properly you should have no issues with sealing, if you have a leak between the plenum and rail, something is bent or improperly installed.