I am still having problems with my intake manifold leaking in the back. This is the second fix in a year. I thoroughly clean both the mating areas with carb cleaner and then lightly sand the areas. I then rub it down with alcohol and make sure that it's completely clean. I use a generous amount of bronze permatex sealant, but I am still having problems.

My question is this: Am I doing something wrong? Is there a better way?

Another question: I am considering using a cork type gasket that comes in a sheet roll. I was thinking about cutting out a piece to fit the areas and use gasket sealant. Has anyone tried this? Is it a good or bad idea. Please share your thoughts and/or experiences. Thanks.

 

use black RTV, apply some to the area after you cleaned it with brake cleaner, don't sand anything, set the intake down on top - don't slide it into place - put your bolts in but don't torque them, just snug them up then wait for a little bit for the RTV to set up then torque the bolts to spec

 

I used a felpro gasket for mine and used the same permatex sealant that you used and mine doesnt leak. Are you possible sliding the intake onto the sealant and pushing it back off of the surface? I also let mine set up without the intake on there for a bit then put it on.

 

Yes, I didn't slide the manifold-just placed it on top as carefully as I could. Also, I waited about 5 minutes after applying the rtv sealant before putting the intake manifold back on. I also waited about 10 minutes before torquing down the manifold bolts. But somehow it still manages to leak.

What do you think about the sheet type gasket made of cork?

I am wondering if anyone has used this and had success.

 

I've never been a big fan of cork, the manifolds came from the factory without any type of gasket just rtv at the ends - do a dry run and see if there is any type of misalignment, like the intake is warped or there is a dent/chunk out of the intake or block, if the intake isn't torqued in proper sequence then it might be twisted, kind of an outside chance but that may be the problem - also are you using LT1 intake gaskets? not regular small block gaskets, maybe some of the other guys might have some suggestions

 

I would use the RTV only for the ends. I can't imagine why yours keeps leaking if done right.

 

I like the right stuff

 

I used a very generous amount of sealant on my Saturn pan as well... thing leaked all over the place. Took it off today to reseal and saw where it was leaking from. I apparently allowed the bead of sealant to "fold" or "wrinkle" in one area.

Summary - just because you applied enough sealant doesnt mean it will smooth out when you close the gap. You need to make sure there's no peaks or valley's or squiggley's when you apply it or those folds could create a path for leakage.

Fully inspect the leaking bead upon removal and you will see the problem. Guarenteed.

 

very good suggestion

 

I had another thought about this earlier today, are you sure it's the manifold and not the oil sensor & associated fittings that are leaking?

 

The other thing is, don't use carb cleaner - It leaves behind an oily residue. Use brake cleaner, or acetone.

 

I use laquer thinner.......I like how it smells, thats why

 

That, and I do not fire up the car for at least 24 hours after the install.

 

Also be careful on how you place the manifold back on the heads/block. It's so awkward to get it back there without it contacting the back surface and rubbing the RTV off the sealing surface. Definitely easier with two people, one on each side of the car so you can lift it straight back and then drop it straight down.

 

use the Right Stuff as mentioned before.

it is VERY Strong and doesn't even have to have a perfect mating surface to seal.

it is what GM uses as the fix for Northstars.