sbc rear intake manifold oil leaks
 

whats the best to seal the intake ? I've been using red silicone for years , but the last two engines have leaked badly , I Even redid it and it still leaked, is the red silicone no good ?

Re: sbc rear intake manifold oil leaks
 

I was having this issue on my super gas sbc. I used black gasket maker (Permatex) and smeared it liberally across the back of the china wall after a thorough cleaning. Hasn't leaked since.

Re: sbc rear intake manifold oil leaks
 

Well at least it doesn't leak out of the back of the manifold anymore. The engine leaks like a sieve, just not from there lol.

Re: sbc rear intake manifold oil leaks
 

Ford TA-31 RTV silicone. Ive used it for years.

https://www.amazon.com/Genuine-Ford-TA-31-Silicone-Sealant

Re: sbc rear intake manifold oil leaks
 

G.M. 10-2006 engine sealant is good stuff also.

Re: sbc rear intake manifold oil leaks
 

Good morning to all,
I've been using the Permatex " Right Stuff " for a couple of years now.
The engine in my Suburban I recently went over the valve adjustment and found a couple of wet area's on the valve cover gaskets - I cleaned and used the Right Stuff on them and that oil leak is solved. No more oil smell while sitting in traffic. I use that on all my small block and big block china walls - zero leaks. It dries quick enough while dyno testing as well. I also use the Permatex Grey silicone with great success as long as you have time for it to properly cure. Make sure the surfaces are CLEAN and OIL FREE.
I found that to be very important in the curing process.
I hope that helps.

Respectfully,
Henry Kunz 1534 H/SA

Re: sbc rear intake manifold oil leaks
 

Permatex Right Stuff!. I’ve never had an intake manifold, water pump, water neck leak on any engine using this stuff for decades and I’m convinced you could lift the engine from the intake manifold without any bolts in it.

Re: sbc rear intake manifold oil leaks
 

permatex ultra gray here. Make sure its not the oil gauge fitting back there. There is no pressure on the back of the intake. Never had a leak there.

Re: sbc rear intake manifold oil leaks
 

thanks for the ideas , will take it apart and give it a try ,

Re: sbc rear intake manifold oil leaks
 

Yup, use the Permatex "Right Stuff" and install the manifold with it wet, don't let it "skin" over. It won't leak.

Re: sbc rear intake manifold oil leaks
 

Mike: after you clean the manifold, do a dry fit to check how much gap you have. Don't assume it's near OEM tolerences. You may need to lay an extra thick bead.

Re: sbc rear intake manifold oil leaks
 

If you are using the rear oil pressure port by the distributor, ensure the fitting is not cracked. I chased a leak for quite a while, and then whola, it broke in my hand while reaching behind to feel for the leak.

Re: sbc rear intake manifold oil leaks
 

Ultra grey or black will not leak,both will cure in oil, sob to clean off but works. been using for years. Also works great for gasket substitution for timing chain, water pump, fuel pump cover, 4sd covers and tailstock etc.

Re: sbc rear intake manifold oil leaks
 

I'll second what Dirk said, good stuff!

Re: sbc rear intake manifold oil leaks
 

I have had great results with Permatex ultra black. Clean the surfaces with lacquer thinner, use a thick enough bead, etc. as others posted.

Re: sbc rear intake manifold oil leaks
 

With all due respect
My limited engine bolting experience have found Right Stuff is awesome seals great is expensive, Ultra works great does the same job is lower cost.
The difference is Right Stuff cures quickly when you need to get the engine running now, Ultra takes a while to cure you have to have some time to let it set up.

Both are great products.


If the china wall or back of intake have been milled for port alignment you will need to apply a high amount of either product to seal. Make sure the distributor opening is clear when it squishes a finger swipe may be required.

Re: sbc rear intake manifold oil leaks
 

In the past I have had problems with this area when the head gasket was a little short of reaching the edge of the cylinder head at the 3 point junction of the china wall cyl. head and the intake manifold. When applying sealant it would not push into the gap left by the slightly short [.020-.040] head gasket by itself. It would leave a gap the thickness of the head gasket under the head at that junction point of the 3 surfaces. Since then I make sure to put a dab of rtv on the inside of the block and using a finger make sure there is sealant forced into that spot before applying rtv to the china wall for the manifold. hope this helps. Dan