Front main seal still leakinh

So i just replaces my front main seal due to.a oil leak. I noticed that i still have a leak after installing the new seal. Im pretty amiture at mechanics. But i am learning i followed YouTube all the way. I know I did the job correct. What could I be missing. Was there something I should have checked. The videos did not mention. Another possibility

Year, model and engine would be a big help. Leaks as well as other problems can be talked about if we know what particular thing we’re discussing.

Often times, it isn’t just the seal itself which is bad–the old seal has dug a groove into the mating surface of the crankshaft. If this is deep enough, a new seal will continue to leak. Hopefully, replacing the seal alone will at least reduce the oil leak to a manageable level.

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You could have nicked the new seal with the end of the crankshaft when putting the transmission in or the crankshaft may be worn as bcohen2010 said.

You can try transmission stop leak which may swell the new seal.

I have seen mentioned a sleeve for the crankshaft but I don’t know what is involved in installing it or if it requires a different seal.

How many mikes on this engine?

What about a groove on the balancer . . . ?!

You may want to try installing an offset crankshaft seal.

An optional design available for several Chevrolet engines has an offset sealing lip. This can be used when the point of contact of the previous seal has worn a groove into the crankshaft sealing surface. The offset lip contacts the shaft at a different point than the original equipment seal, preventing oil leaking through the groove and eliminating the need for expensive crankshaft repair or replacement.

FEL-PRO sells them.


If the harmonic balancer has a wear groove in it then a new seal will leak also. That is when these items are needed. You may need to redo this job to stop the leak.

A wear groove on the harmonic balancer is fairly common, in my experience

You just heard from 3 of the most knowledgeable posters on the site. Hint; I am not one of them, no DIY does enough work to gain the experience of a good pro.