General question about crankshaft seals.

[Thom Pintello]

How long do they last? Is their longetivity a function of time? Or is it mileage? Thanks in advance.
Thom

Well, it's dependent on both time and mileage. Also temperature will play a part in how long they last. I've replaced them at under 50,000 miles(warranty work) on some cars. Why do you ask? What model do you have?
Regards,
Randy D.

[Thom Pintello]

Randy,
Thanks for the response. I've just taken possesion of a 1969 280 SEL and the thought just crossed my mind. Actually it was my experience with a 1972 220 that made me ask. It leaked oil like a sieve and left me permanently traumatized.
Thom

Hi Thom,
Okay, I understand now. On the older cars(like mine)the rear crankshaft seals are considered a last resort unless the engine needs a lot of work anyway. I think anything over 150K to 200K miles is lucky. But they can "seep" for years and years. They usually have to be leaking real bad to warrant replacement.
I pulled the engine out of my 6.3 two years ago to fix the rear seal with 140,000 miles on it. Mine was leaving puddles. Of course I needed to get all the stuff on the engine re-plated and replace some other pieces as well, but I really don't like the old "rope seals". They are a serious pain to do!
Regards,
Randy D.