RTV on head gaskets = how bad?

[mo_dingo]

I know it's a bad idea. But I am just curious if anyone has actually done it and can report actual problems or lackthereof.

I was helping a guy at work try to get his motor back in his blazer after being rebuilt. Just when we get the motor mated to the transmission, I noticed a bit of blue stuff coming out from the deck surface. I just went and asked him "WTF is wrong with you???" So we yanked the motor after all that work to redo the heads.
Scott

 

[94Blue302GT]

that stuff can't hold the pressure of a cylendar. Normally, i get the felpro gaskets with the sticky already on them. HOwever, i haven't run them with the turbo yet.

 

[mo_dingo]

that stuff can't hold the pressure of a cylendar. Normally, i get the felpro gaskets with the sticky already on them. HOwever, i haven't run them with the turbo yet.

Plus the heat. I doubt it would withstand 600*F temps; even the high temp stuff.

But I am still curious.
Scott

 

[AznStanger3v]

it will stand the heat. ive used orange rtv as a gasket replacement on my old bosses run around truck and it work beautifully. using it on the head gaskets isnt a bad idea.... its a horrible idea.

 

[mo_dingo]

it will stand the heat. ive used orange rtv as a gasket replacement on my old bosses run around truck and it work beautifully. using it on the head gaskets isnt a bad idea.... its a horrible idea.

Thanks for the reply. I wonder how long it will last.

Yeah the orange stuff is the high temp stuff that I always use, better than the blue he used.
Scott

 

[OrangeMustangGt]

yeah, BAD idea.

although my felpro mls gaskets use some type of rubber on the metal surface.....must be super high temp, but hell it works!

 

[zZsKyZz]

We have tons of permatex stuff at work.. The stuff that says 600* RTV silicone or gasket maker does <B> _NOT_ </B> do well under heat. A customer came in with some of it on a piece of metal and I was able to burn it off with a lighter.

Doubt a lighter gets up to the temp. of your heads.

 

[rulesR4suckers]

using it on the head gaskets isnt a bad idea.... its a horrible idea.

funny and true

 

[Brozz]

No type of sealant/RTV should ever be used on head gaskets. The only time I've ever seen such a thing is when hackers are trying to compensate for a warped head/deck.

 

[Richter12x2]

Some idiots that did the last headgasket swap on my wife's car apparently used dots of RTV to hold the gasket in place (As if the locating dowels weren't enough!) It makes a lovely circular char mark on the block that takes forever to get off with a razorblade. They also told her that they were installing copper gaskets so that they would never blow again, and they charged her $150 for them. When I pulled them off you can still see the blue stripes from the $12.00 Felpro gaskets! That's why I don't like to let anyone else work on my cars.