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Front and rear valley oil leak from intake manifold.
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Front and rear valley oil leak from intake manifold.
When I built my engine I used some aftermarket aluminum heads that were made and drilled to accept both vortec and non-vortec intake styles. My first manifold was a victor jr. 4x4 (non-vortec) and it always had a small persistent lead from the passenger rear of the valley (where the intake meets the block). It was installed using the gasket-maker as the sealant in the valleys (from everything I have read this is preferred to the rubber gaskets in the kit). Late last summer I re-installed the intake the same way and while the rear was sealed I started having a small oil spray leak from the front of the valley at high RPM's.
At this point I decided to try an use another new in box intake that I had around. The Victor was used, and I really had no idea how worn it may be or if it was warmed in some way. So late last week I installed this new intake (non-vortec style as well) and once again used the sealant for the valley gaskets. Yesterday I fired it up and at idle everything seemed perfect. However, as soon as I took it out for a spin and got back I saw that it was leaking from both the front and rear...bad!
Just wondering if anyone has ran into this problem before and has a solution. I know that there are going to be some to say get the vortec intake and go that route, and honestly, I may have to end up doing that. However, I would like to find a solution if I can, I mean the heads were made to take both intakes so it has to be possible. To me it seems that the intake itself is sitting too high off of the valley area causing it not to seal. I am using regular old fel-pro gaskets and I was thinking maybe they are too thick. I looked it up though and angle of the head doesn't change between vortec and non-vortec, so that may not be the answer either. I have also thought about redoing it and essentially putting a "great wall of sealant" on the valley areas to having it squeeze out real good when I put the intake on. Unfortunately, this seems like it may lead to trouble as well. Just looking for some insight.
Re: Front and rear valley oil leak from intake manifold.
Originally Posted by TTOP350
What I use. Dont drive the car for atleast 12hrs after.
Used ultra black for the first two installs. This last time I went to Ultra Blue, because I saw some people saying they had better luck with it. Guess I'm out of luck wither way.
Re: Front and rear valley oil leak from intake manifold.
I re-did mine twice. the first time used black rtv. second time I used motorcraft sealant from work and put it on thick. like a stack of dimes across. and has not leaked since. The biggest thing is putting intake on straight and not moving it. I used Indian head to hold intake gaskets in place then use silicone across front and back
Re: Front and rear valley oil leak from intake manifold.
The color doesn't matter, any more than the color of a car makes it faster.
Personally I prefer the "Right Stuff" stuff; not so much because it's "better", as much as, I'm lazy, and letting it kinda ooze itself outta the can all by itself rather than me having to squeeeeeze the tube, just appeals to my lazy nature. Butt hay....
The trick to getting it to work, whichever poison you choose, is:
First get the surfaces ABSOLUTELY PERFECTLY FLAWLESSLY SPOTLESSLY IMMACULATELY CLEAN with a razor blade, scraper, sandpaper, Scotchbrite, wheel of death, etc. Then STERILIZE the block and intake with lacquer thinner. Then smear a nice schmear of sealant on the block, maybe .030" - .050", then let it sit for a few minutes. Then lay a bead straight outta the tube on top of that, round, the same height as the width of the "china wall". Then you let that sit for about a half hour if it's hot out, up to about 2 hours if it's freezing. Then splooot a splooot in each corner and set the gaskets onto the head flanges and secure them, and add another sploooot on top of the corners. Then schmear about the same amount you did on the block onto the intake surfaces, and set the intake on, start the bolts, and tighten em about screwdriver hand-tight. (5 ft-lbs MAX) Then wait about another half-hour (or up to 2 hours, depending on the ambient temp). Then torque it down.
The wait between laying the thick bead on and setting the intake on is THE KEY.
I use clear box tape in the spaces near the exhaust crossover to hold the gaskets in place.
Re: Front and rear valley oil leak from intake manifold.
And the trick to keeping the seal in place after it's been dried and torqued is to make sure you have a 100% functioning PCV system . A blockage of the air inlet , with a source of vacuum still being applied to the PCV valve can cause the seal to be sucked in . A blockage of the vacuum source , coupled with a bit too much blowby , can push the seal out .
02-09-2016, 10:01 AM
And the trick to keeping the seal in place after it's been dried and torqued is to make sure you have a 100% functioning PCV system . A blockage of the air inlet , with a source of vacuum still being applied to the PCV valve can cause the seal to be sucked in . A blockage of the vacuum source , coupled with a bit too much blowby , can push the seal out . 
