lower intake leaking coolant.edl lower and tfs heads

Wow, that sucks.
Does the leak develop on both sides?
Did it leak before you had the heads milled?

Milling the heads down can have this affect. I believe the intake can be shaved to correct for this though.

Have you checked the clearance between the head and the intake without a gasket in place? This should give you a good idea whether or not the there is a mis-match between the head and intake.

best of luck
hope this gives you some ideas
jason

Have you retorqued the lower intake bolts with the engine hot/warm after running the engine a bit after the install???

This has been a problem for many and usually takes more than a few lower intake retorque sessions.

I`ve retorqued mine now for the third time to eliminate a minor leak at the front coolant ports.

OT,just a tip.When installing the lower intake manifold I use 4, 4"x5/16" bolts with the heads cut off as guide pins.Lines up perfect the first time.

just use silicone or rtv sealant for the end seals, dont use any gaskets on the front or back ends of the block.

You can use Hylomar gasket sealer around the ports...beautiful stuff with unlimited assembly time and better than silicone in this application.

But as I said,it may take more than a few retorque attempts before the gasket finally compresses fully and seals up.

I had my gasket slip down on me when I dropped the intake on before (see above pic). For me it caused a vac leak to the lifter valley. With different port patterns, gasket shift could cause coolant leaks. The studs I used help, but I had to use silicone to keep the gasket from shifting during assembly. Just a couple dabs, then let it set up for a while.
The above advice on re-torques is sound. I haven't needed to re-torque since converting to studs though. I am sold on studs for the intake. Then again I don't break out the torque wrench for the lower intake, so they are probably all over torqued.
:Word:

vristang said:

I had my gasket slip down on me when I dropped the intake on before (see above pic). For me it caused a vac leak to the lifter valley. With different port patterns, gasket shift could cause coolant leaks. The studs I used help, but I had to use silicone to keep the gasket from shifting during assembly. Just a couple dabs, then let it set up for a while.
The above advice on re-torques is sound. I haven't needed to re-torque since converting to studs though. I am sold on studs for the intake. Then again I don't break out the torque wrench for the lower intake, so they are probably all over torqued.
:Word:

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Hylomar gasket sealer that I mentioned will hold your gaskets in place like you wouldn`t believe.

ok try this.....pull the intake, clean it and the heads. if you dont have studs, make a couple and install them on opposite sides of the lifter valley in the manifold bolt holes.
get some grease, and put a bead of grease maybe an 1/16 inch thick, or about what the gaskets would be plus some silicone.....put that all around the mating surface on the heads.
then, slide the manifold down on the studs untill its seated firmly, then pull it back up and look to see if the grease is flatened or where maybe it hasn't been touched, and that should give you an idea of maybe where you need to put more sealer or atleast mabe where the problem is.....and how far off it isn't making contact.....hope this makes sense.....
you can also put a complete skim coat of silicon on the manifold mating surface, and also on the heads under the gasket to help thicken it up some and maybe shore up any low spots.....this i have done before with no problems. i have also heard of people who don't even use intake manifod gaskets, they only use a certain type of silicon around the ports and water jackets and dont have problems...although that method i have not personally tried......but it's a possibility.....to do that i believe you put the sealer on then lightly set the manifold on, let it dry for awhile before torqueing it down.

cool idea with the grease!

The white paste used for checking rear end gears comes to mind.

You may be able to see a difference in gasket thickness after removal as well, assuming it comes off in one piece.

The next time I have to pull the manifold I will try some Hylomar, thanks 8950ho.