Hi
I have a '64 Cutlass, recently I noticed an oil leak above the valve cover gasket. Oil was pooling in one place. (see pics below) I had the valve cover gaskets replaced but it is still leaking in the same spot. I had someone look at it who suspects that the intake manifold gasket needs to be replaced. I spoke to another person who says that there is no oil in the intake manifold and
does not think that is the issue. The car has a throttle body ignition, so the Intake manifold was replaced at some point. I still have the original. I am attaching pics. First pic is the general location of leak, second pic is closeup, third pic is intake manifold gasket which does look somewhat chewed up.
So what do you think?



Oil leak is here

Oil pooling next to bolt in middle of pic

Intake Manifold Gasket

 

Remove that bolt, clean the threads on the bolt and hole, put some thread sealant on it and reinstall.

 

Eric,
Thanks for getting back to me. Are you talking about the bolt in the second picture next to where the oil is pooling?

 

Yes

 

Great, thanks I will give that a try.
Rick

 

Looks like you have burn through at the exhaust crossover heat riser passage. Remove the intake and replace the gaskets with the style that has block off shims.Use Teflon thread sealant on all the bolts.

 

Wouldn't that result in an audible exhaust leak?

 

Eventually if it gets worse, just basing it on the discoloration pattern shown in picture.

 

Hi
Thanks for the feedback. I have done as Eric said and removed the bolt, it came out pretty easy and is not messed up at all.
I put it back with some sealer, we'll see if that solves the issue for now.
If not guess I will be trying this. Don't know the what block off shims are though.
Do you have a recommendation as to exact gasket to buy?

 

Look into Fel pro for gaskets and Mondello Performance has block off plates, I'm sure there is more info on this subject elsewhere on this site.

 

Still having problem with this oil leak, I am now being told based on new pictures that the oil is probably leaking from the head. I can see where it is leaking out below where the valve cover attaches to the head. So apparently I have to remove the head to see if it is cracked and if so find a new head. Can anyone see anything in these pictures that might know more about this? I know it will be a big job. Appreciate any advise.




After running the engine for a few minutes the oil starts leaking down from below the valve cover.

 

I can't tell from your pictures,but is the crankcase ventilated in some fashion? IE: breather, pcv valve? It still looks like a leaking valve cover gasket.

 

The valve cover gaskets were already changed, it is still leaking from the same spot.

 

The oil leak is NOT coming from the head, at least not from a crack. There are no pressurized oil passages in the head. Oil to the rockers flows up through the inside of the pushrods. Any leakage flows back down into the valley through the pushrod holes by gravity. That leak is oil from the valve covers. Aftermarket aluminum covers are notorious for this. Remove the covers, clean the mating surfaces thoroughly with lacquer thinner, use new gaskets, and glue everything in place with Permatex ultra black. DO NOT overtorque the valve cover bolts. Let the Permatex cure overnight before firing the engine.

 

Thanks for the reply Joe. It's a relief to know that I won't have to deal with the head.
It is a little confusing though. I am supplying the same picture again but if you look, the green arrow is the bottom
of the valve cover and the red arrow is where the leak seems to be coming from. There is that black strip of metal (dark grey actually) between
the bottom of the valve cover and the head, and the oil seems to be coming out of the bottom of that strip on the head side. I'm not sure what the strip of metal is.

Either way I am taking it back to the guy who did the valve cover gaskets in a few days.
Thanks Again.

Green: Bottom of valve cover Red: Where leak is coming from.

 

The strip of metal is the metal intake gasket. Gravity makes it puddle there, If it is actually coming up from there, it's splash from the valley seeping past the intake. That is highly unlikely, but check the torque on the intake bolts. The reality is that any looseness there would cause rough running that would be a bigger problem than this leak.

 

Thanks I will check it out. I still have the original valve covers, maybe I should put them back on.
They were replaced, I assume, along with the original intake manifold (which I also still have) when they put the Howell Throttle body injection system on,
before I bought the car.

 

Hi,
Just thought I would follow up on this topic. It did turn out to be the intake manifold gasket. I had it replaced and the oil leak is gone.
Car is running a little better as well so there may have been an exhaust leak there. Thanks to everyone who helped me diagnose the problem and get it fixed.
I have another question I will post to this forum now (there is always another question.)