Manifold oil leak

68 vette with a 400ci engine. Problem! I noticed oil leaks around some of the manifold bolts. and it also burns a little oil.

The burning oil can be either rings, valve seals, or PCV system. Check out the PCV first. Then see if the car produces oil smoke when first started. If it does and then clears up the problem is the valve seals. If it smokes later, it's rings. If it doesn't smoke it's harder to tell.
The bolt leaks can be sealed by loosening the bolts one at a time, using brake parts cleaner to remove the oil, and putting a small amount of silicone sealer on, then retorquing the bolt. Do it one at a time.

Ken Styer

i have the same problem with my 79- gonna try that too
thanks

just to add to what Ken said. Be sure to chase the threads in the manifold.

Chase the threads? Are you saying tap it? or silicone the manifold threads as well?

Great tip to stop manifold leaks, just want to make sure I do it correctly.

Bret

Chasing the thread means running a tap down the existing thread to clean them and make a good gripping surface with out damage. Bad threads cause increased friction when tightening the bolts. This would throw the torque off and leave the intake gaskets a bit loose. Clean the holes as well, before installing the bolt. Compressed air works well. If you use chemicals, make sure the hole is empty and dry before installing the bolts.

Ken Styer

I found a neat little tool thingy at my local fasteners store. Vermont American makes a thread cleaner set. Very similar to a tap and die, but not as aggressive. It's inexpensive and does a great job of cleaning existing threads whether rusty or grungy. Much cheaper than a tap and die set. I've gotten to where I use it on almost everything I take apart. Sometimes I even put the stuff back together!

Thank you both, Ken and Dave.

I will look for the hole cleaner kit you mentioned.

Bret