Manifold gasket leak

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Manifold gasket leak

Postby Monzadude » Sat Apr 12, 2008 10:15 pm

I put the intake manifold on but when I filled the rad with coolant I noticed that the manifold gasket is leaking. A very slow dribble. It's leaking from near the front bolt on the drivers side. It's a new gasket and the bolts are all tightened to the specs in my shop manual. Certainly tight enough.

What now? I tried to tighten them just a little more but it made no difference. The motor isn't running yet and it leaks just sitting there. I've never used silicone gasket with the metal one. If I remove the intake is the gasket garbage or can I maybe add a bead of silicon and re-install it?

I checked and the intake, the block and the heads they were all clean before I installed it. Everything looked clean and straight. Also double checked before I installed it to make sure it's the right gasket.


Bill
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Postby Sirshredalot » Sat Apr 12, 2008 11:40 pm

JUst depends on the type of gasket that was used.

The blue felpros with the steel cores can be reused if theyre not too crushed.
Also...Did you torque it in sequence?...Like a wheel needs to be torqued or a head, the intake has a specific torque sequence.

I always use sealer on my intake manifolds...some say its ghetto...but the only time I didnt use sealer...it leaked.

I coat both sides of the gasket with RTV...preferably copper or grey. and then smooth it on real thin with a finger...I also never use the front rubber seals if your engine is so equipped....I use a thick bead of RTV and then let it set up for about 15 minutes before setting the intake.

If you take the intake off...Set a flat/straight edge on the head surface of the intake and see if its warped....just because its iron doesnt mean that it wont warp...if you ask me iron warps easier than aluminum.

Does the 3.8 use a valley pan? Never had the manifold off one...if it does that you should be able to reuse it.

God bless
-Shred
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Postby Sirshredalot » Sat Apr 12, 2008 11:40 pm

JUst depends on the type of gasket that was used.

The blue felpros with the steel cores can be reused if theyre not too crushed.
Also...Did you torque it in sequence?...Like a wheel needs to be torqued or a head, the intake has a specific torque sequence.

I always use sealer on my intake manifolds...some say its ghetto...but the only time I didnt use sealer...it leaked.

I coat both sides of the gasket with RTV...preferably copper or grey. and then smooth it on real thin with a finger...I also never use the front rubber seals if your engine is so equipped....I use a thick bead of RTV and then let it set up for about 15 minutes before setting the intake.

If you take the intake off...Set a flat/straight edge on the head surface of the intake and see if its warped....just because its iron doesnt mean that it wont warp...if you ask me iron warps easier than aluminum.

Does the 3.8 use a valley pan? Never had the manifold off one...if it does that you should be able to reuse it.

God bless
-Shred

PS: Your carb will ship tuesday.
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Postby Monzadude » Sun Apr 13, 2008 12:20 am

Yes the 3.8 does use a valley pan. The intake's aluminum.

Come to think of it, I started to use the torque pattern but had to get longer bolts. The factory bolts were too short for this intake. I thought they were long enough before I started but they only grabbed a few threads.Can't remember if I continued after getting the new bolts. I might not have.

I wonder if maybe I just undo them all and re-torque making sure to use the proper pattern.

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Postby cammerjeff » Sun Apr 13, 2008 8:12 am

Oh is a 3.8 Huh, Well then if you are putting an intake on a used engine, Not only would I use sealant on the colling passeges, I would also throw out the rubber seals at the front & rear of the intake, and use a product called "The right stuff" Sort of like thick black RTV. It is the only way I have been able to keep my Aluminum Intake from leaking oil at the rear flange.
Also anouther problem area on a 3.8 or 4.1 with aluminum intakes is the thermostat housing seeping, try to get the heavy cast iron on they but on the later 3.8's with the aluminum intake's. It solved my seeping problem.
Anouther thing to consider is the intake new or used? If used it may have been milled to fit a specific set of heads, I always etch how much was taken off each side, but most people don't bother. You may have to double gasket if this is the case.
Good luck with it!!!
Jeff R

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Postby Monzadude » Sun Apr 13, 2008 2:38 pm

So I took of the intake and cleaned it up again. Checked everything and it all looks fine. This time I used Permatex red high temp gasket maker. I put a thin coat on the heads then put the gasket back in. Then put a thin coat on the gasket and put the intake back on. I made sure to tighten it useing the proper torque pattern. So far everything looks great. No leaks!

Hopefully when I get the motor running and the pressure builds it still doesn't leak.

Turns out the thermostat housing was leaking a bit too so I just put some gasket maker in there and it looks good now.

The front and rear rubber intake seals already had gasket maker on both the top and bottom of them so they won't leak oil. I've had that problem before and knew to prevent it this time.

Thaks for the help

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