The Stovebolt Site Forums The Shop Area The HiPo Shop GRRRRR oil leak

After getting the SBC fired up I had an oil leak back near the firewall on the left hand side. Pulled the intake manifold and put new gaskets and RTV on. Put it back together and the oil leak is still there! Tomorrow I pull the left cylinder head and replace the head gasket. Near as I can tell looking in a mirror with a flashlight the oil is coming from between the block and head. I hate doing things over again!

check your oil pressure sender [or tube] closely before you pull a head

Bill

Make sure you don't use the end seals that come with your intake gasket set. Just use a 3/8" bead of silicone. Also, make sure your valve cover gaskets are on properly. There isn't much pressure up in the heads except for the push rods. Everything else is drain back.

On the left side are a few pressure ports. Usually with plugs or the sender. You also have the filter on that side. Make sure all your plugs are tight.

Sometimes your mirror will show some assembly residue. One way to find the leak is to dry everything with a degreaser, then run the motor through a heat cycle.

I chased mine for 3 years until some installed the intake manifold gasket properly I replaced everything previously to no avail.

Did you seal the bolts on the intake manifold ?
I had oil leaking from there, and flowing along the lip of the valve cover, then dripping down the left rear side of the block.

MNSmith is right don't use the rubber seal that gose between the heads load it up with a good bead od silicone. I see that problem alot.

Found the problem. There is supposed to be a 1/4NTP plug in the back of the block (under the cyl head but near the oil sender) that allows the oil gallery for the sender to be drilled. During a previous lifetime, some idiot had jammed a 3/8-16 plug into it. I pulled it out and tried to seat it and could tell things were not fitting correctly so I ran a 1/4-14NTP tap in the hole. What do you know? It fit correctly. Then I measured the plug and could see that it was a 3/8-16.
Got the correct plug and everything is fine now. Kind of scary what some nimrods will try to get away with.

One day I was doing some welding on my '49. I had to pull the motor to do it. When I got the thing high enough, I found that the 327 had cracked water jackets, right between the freeze plug holes, that were patched with JB Weld or similar. Well, it didn't leak antifreeze, so when I was done welding, the motor went back in. Never had any leaking antifreeze issues so I just ran it and ran it.

Glad you found the leak and were able to take care of it.

Thanks. When it first started puking oil I was thinking "C'mon, how did I screw this up?" Was kind or relieved that it wasn't my doing. I know how hard it is chasing oil leaks down.