Are rear exhaust manifold bolts open to crank case or oil passages?

[67CBodyGuy]

Are the rear exhaust manifold bolts prone to leak oil? I see smoke coming from under the very end of the exhaust manifold on the passenger side (cyl 8). I haven't seen this before there. I have new rubber valve cover gaskets with steel liner. I had a problem like this on the driver's side, I flattened the surface of the cover around the bolt holes and put permatex ultra-black on it, it stopped smoking after I did that. Now I'm seeing this on the passenger side, I don't think I'm seeing oil leak down from the valve cover, but maybe it's happening now.

I'm just wondering if there's any way that oil gets past the rear manifold bolt holes.

 

[Kendog 170]

Small block? Just coolant. Is it steam not smoke? Most add sealer on threads of front and rear exh. manifold studs.

 

[RustyRatRod]

Neither. They are open to the water jacket.

 

[Oldmanmopar]

I use studs with sealer on all 4 even with headers.

 

[67CBodyGuy]

Well, maybe someone can explain something here. I'm seeing what looks like oil in the white circles. The lower one is just a bolt and probably coming from above. This is looking up on the passenger side. Is this a head gasket leaking? I took the oil pressure switch out a couple weeks ago and screwed in a gauge there (temporarily) just to measure oil pressure. Cold pressure at fast idle was 65 psi, at warm normal idle was 60 psi. This is new oil, 10w30. Is this pressure to high? I read all sort of things about what is normal oil pressure. Anyways, this leak drips onto the exhaust pipe and is smoking, it's not much. Is there an easy fix?

 

[mygasser]

it'll either be the rear of the intake or the valve cover gasket and running down from there.
neil.

 

[4spdragtop]

Oil psi isn't too high, mine has 80+ cold and driving. Warmed up 65 driving. Pcv hooked up? For any of my bolts leading to liquid I used Permatex hi temp. Pricey but leak free!

 

[Rocket]

it'll either be the rear of the intake or the valve cover gasket and running down from there.
neil.

Aside from the above recommended items to check, I would also check the oil sending unit near the distributor and the base of the distributor itself at the back of the block for oil leaks.

 

[67CBodyGuy]

Yea, it appears to be coolant that's leaking out the outer manifold bolts (studs) on the passenger side. I think both studs. Only when hot / running. I'm going to drain a gallon or two of coolant and then take these studs out. I had the manifolds off a few months ago to get cleaned and coated, I recall that one stud of the 4 came out but I don't remember which side.

I would have said this was burning oil by the smell / smoke, I guess that 50:50 antifreeze smells and smokes just as bad as oil on a hot manifild?

Do I have to worry about the other bolts leaking coolant or is it just the outer studs?

Unless there's any objections I plan on using Permatex 592 thread sealant.

 

[4spdragtop]

I used Permatex Hi temp sealant on all manifold bolts. Expensive but it works

 

[67CBodyGuy]

What's the difference between these two? One is what Permatex has on their site, the other is what Canada Tire sells. Different Permatex P/N ?

 

[4spdragtop]

Good question, chk Permatex website out?

What's the difference between these two? One is what Permatex has on their site, the other is what Canada Tire sells. Different Permatex P/N ?

View attachment 1716314156View attachment 1716314157

 

[67CBodyGuy]

I tried some of this thread sealer stuff on a relatively new nut and bolt. After 24 hours, the stuff that was exposed was still soft, same as it came out of the tube. But the stuff that was on the threads must have cured - I can't twist the nut by hand. So I guess it does work...

 

[RustyRatRod]

What's the difference between these two? One is what Permatex has on their site, the other is what Canada Tire sells. Different Permatex P/N ?

View attachment 1716314156View attachment 1716314157

I don't use that kinda stuff. I've seen it dry up and flake off and start leaking. I use the Permatex (store brand) red high temp RTV. Never had a leak.

 

[4spdragtop]

Did u find out the difference between the 2 Permatex? I'll chk which # I have when I get home.

I tried some of this thread sealer stuff on a relatively new nut and bolt. After 24 hours, the stuff that was exposed was still soft, same as it came out of the tube. But the stuff that was on the threads must have cured - I can't twist the nut by hand. So I guess it does work...

View attachment 1716315336

 

[67CBodyGuy]

Did u find out the difference between the 2 Permatex? I'll chk which # I have when I get home.

If you do a search for Permatex 59206, all you find are links to Canadian retail pages. Permatex website has nothing on that P/N.

 

[4spdragtop]

59234 is what I use. W/p, v/c, exhst bolts, all leak free on fresh 340.

 

[67CBodyGuy]

I think 59234 is the P/N for 50 ml tube, and 59206 is P/N for 6 ml tube. Same stuff otherwise. Both are likely Canada-only P/N's.

From Permatex.com Catalog-Canada: