oil leak?

[74chev4x4]

74 chev 350 4x4, been tracking an oil leak for a while now, finally found that its coming from the passenger side on the back of the motor.  It leaks down onto where the tranny and motor meet and then onto the starter and headers.  The intake is brand new so my question is would it be likely to be coming from the dist?  It only seems to happen when driving cause if I let it idle it will not leak till I start driving then she leaks pretty good.  Is there anything else back there that could leak, oil sender is fine I checked.  Any ideas would be great.

[beastie_3]

If it only leaks when you drive it, I would wipe it clean and look at the area while someone else holds the engine at a higher rpm.

[74chev4x4]

yea I did that, the oil is brand new and clean so its hard to see, I think it just dribbles out and runs down then makes a mess, what would ur best guess be as to where its coming from up there?

[74chev4x4]

anyone have a pic of the back of the motor where it meets the tranny, I cant get a good look.

[74chev4x4]

if its at the rear of the intake can I just use some rtv around the leak to seal it up?

[beastie_3]

no because you need to get rid of all the oil on the surface first. you wont be able to do that unless you pull the intake and clean the surfaces real good.

[Swims350]

most oil sending units are on the ds beside the dist. it could leak from the dist. but I'd bet intake unless it's a valve cover, they can leak down and get in the same spots as you mentioned.

[74chev4x4]

No its dry behind the valve cover, wet behind the intake on the seam I will look again to be sure!

[Swims350]

see if a gasket was used or only silicone/rtv, or if the gasket is pushed out or sucked in, that happens sometimes. You might slow it down a bit by using brake kleen or something to spray in there to clean it, then rtv it, but you aint gonna stop it unless you take it off and redo it.

[74chev4x4]

I put a brand new edelbrock intake on before I put the motor in used there gaskets too. If I recall there were no gaskets for the front or rear I used rtv.

[Swims350]

that's probably your leak then. Some ppl use the gaskets others don't I use em, but they can push out or suck in esp. if you don't drop the intake exactly dead on the first time. Same goes for rtv it has to sit dead on the first time or the rtv bead gets moved around and spread out. Personally I never trusted a bead of silicone only to seal it up. esp. not when you can have 60 psi or more oil pressure.

[Captkaos]

There isn't 60lbs of oil pressure under the intake.  I never use the seals as they generally leak.  You also should run the bean on the ends and let it skin before dropping it on.
If it isn't coming out of the sending unit I would suspect the silicone seal though.

[Psycho71]

Interesting thread. I like seeing new and different ways of doing something.

  (As I learned from my dad)- I always used  the rubber gaskets on the end of an intake. I rtv them the to (cleaned) block, let sit overnight, then a light coat of rtv on top of the gasket and a good dab in each corner, then very carefully place the intake on and tighten it down. Always worked for me. But it is cool to see others' ways of skinning the cat.

[Swims350]

That's almost exactly how I do it, I thin coat rtv on the clean and oil free block, usually use my gasket removal things on the right angle air grinder, then brake kleen it off with a rag, smear a thin coat on, stick a good dab in each corner, throw the gasket on right away, dab the corners, smear a thin coat on top of it, and throw the intake on it right away. I also use dabs of rtv to hold the side gaskets in place and rtv the bolt threads to try and stop the oil seeppage.

[74chev4x4]

Got the leak guys it was the manifold for sure, put those new front and rear gaskets on siliconed it let is sit over night put her back together and no leaks thank you.