Question : RTV Intake Manifold?

[pgtr]

When replacing the intake manifold gaskets on an '84 GM 2.8L V6:

Q: Should RTV be put on BOTH sides of the water jacket area of the gasket? Or one particular side (head or intake side)?

Q: Should any RTV be applied to other areas of the gasket such as around the intake runners?

Q: Do any of the bolts have special considerations such as applying sealant to their threads?

Which RTV would be best? I have black and gray. (black seems to cure a little softer - the gray is popularly spec'd for some import applications and seems to cure harder )

thanks

[geoffinbc]

Only use it on the intake valley ends. Not on the gasket. Be sure you are using the heavy duty Felpro gaskets. They are metal with seals at each port and the water jackets.

No sealant on the bolts but GM specs thread locker so they don't back out. You absolutely MUST torque every bolt to spec with no exceptions. If you don't do it do not expect anything to last.

[1988GTU]

I would suggest new bolts IF you can find them (GM should have them) . Make sure there's no pitting and that the surfaces are true while also really clean. Dont use the RTV that comes in the kit (box), use the GM recommended sealant or high temp black rtv. It doesn't hurt to dip the bolts in some teflon goop, but if you should need to do it over again, cleaning the holes and bolts will not be easy.

[geoffinbc]

No the bolts should use thread locker. There is no reason to use a thread sealer they do not enter a water jacket.

[pgtr]

OK - thanks, appreciate the responses!

Q: What harm would be in applying RTV to the water jacket opening?

[When working on Chevy SBs I used to always apply a small layer around the water jackets on those engines. I discarded the rubber 'valley' gaskets. But apply a bead across the valleys instead. Let it skin over a little. And drop the manifold on]

A: Yes I have the Felpros. I don't know if they are the same ones mentioned above but it 'looks' like there is metal sandwhiched between gasket material on both faces.

[geoffinbc]

Because old gaskets were paper and seemed to work fine without or without RTV. But the new gaskets are "rubber" (for lack of a more accurate term) and RTV will inhibit their sealing.

[1988GTU]

Just use RTV on the valley section where the gasket doesn't cover. Install a dry gasket with no coating on it anywhere else.