Does anyone in the registry have an engine in their C3 that doesn't leak oil from the front main seal? I have rebuilt the 350 in my '75 twice, (had to do it a second time because of machine shop screw up) and it leaked oil both times from the front main seal. What is the secret to building an engine that doesn't leak oil? I would love to know.

Is the harmonic balancer original? If it is, then there is probably a groove worn into it where the seal rides. One of 2 ways to cure it.
1: Pull the balancer off and have a machine shop put a "wedding band" on it. It's basically a metal sleeve that gets pressed on. This gives the seal a new surface to ride on.
2: Put a new balancer on.
And I always put a dab of RTV black around the keyway area before putting in the bolt & washer in on the end of the crankshaft. (but after you slip the balancer on.)
This will help prevent oil from seeping past the keyway and out the front of the balancer.
Good Luck!
Sarge

I agree with sarge, plus a new way. The latest front cover gasket set I bought came with a front seal 1/8" longer than stock so it sealed against a new part of the dampener. Just make sure the area is clean and smooth. Joe

BTW, those sealing sleeves are available at NAPA with a $5 tool to drive them on. Cheaper than paying a shop to do it.

Thanks for the tip guys, but both times I put a NEW repair sleeve and NEW seal on it and it still leaks. I even replaced the front main seal in the 350 in my GMC Truck and used a repair sleeve and new seal....Still leaks. I am very meticulous about my vehicles and the work I do on them, so the parts were good and clean and I was careful to not damage the seals when installing them. But they still leak! Any other suggestions? Thanks.

Mate over here in Oz we have a car called a ford Falcon i think you have them over there To anyway they had a problem from brand new and what we did at the dealership was take the coil spring out of the back of the seal and cut it twist it back together to make it smaller dont take a lot out it wont need much this sould work. Its worth a Try practise on an old one 1st Hope this has helped!! chers Mick

I think Micko is on the right track. Did you have the front cover off to install the seal? If not, be sure to fill the cavity around that spring with vasaline or lithium grease to keep it from popping off-and be very careful not to beat on the cover too much. If the cover was off be sure it is not bent/warped. If the cover is warped, it will have the seal cocked in effect and it will leak. The front seal leaking is not nearly the problem of the rear main seal-they are notorious for weeping until they changed to 1-piece seals in the mid 80s. With a clean, straight cover and a correctly installed sleeve you should not have had a problem.

|UPDATED|8/4/2003 7:19:44 AM|/UPDATED|

Guess I must be lucky. When I first bought "The Toy" it didn't leak a drop. Then I began to notice a couple of drops after it had sat for a few days, then a few more drops. The last time I had it up on ramps changing the oil I put a socket on the oil pan bolts - end of drips.

There is hope, my '69 350 actually leaks less than my '97 maxima.

Actually, I don't think the 350 leaks at all.

Hi
When you install any new seal,be sure to smear some
grease on the surface rubbing on the seal so it doesn't
tear the seal!
Steve

Hi
All 25 year old cars

leak oil somewhere!
Steve