I need to ask a question. Is there a bit of a groove and/or ring mark in the crankshaft where the journal spun against the seal? If there is, there is a chance that the new seal could leak too. After a hundred million revolutions, the seal will wear down, but it can wear a bit of a groove in the crank too. I once replaced one in a Jeep 4.0 straight 6, and there was a pretty good groove in the crank. After several hours of nasty, dirty work, the new seal leaked also.
