Rear Crankshaft Oil Seal

[david.g.chapman]

In the course of my work on the engine, I have noticed that the rear crankshaft oil lip seal has gone hard over the last 18 years, but the front seal has stayed soft over the same time.
I am changing both seals of course, but I am wondering why the rear seal deteriorated so much, probably due to heat?
I suppose heat soak from the combustion chambers and the hot oil have done the damage. The engine has spent its life with 80 to 90 degree coolant, but I'm not sure about the oil temperature.

Have other owners had the same experience?

Dave Chapman.

[h20hamelan]

I suppose the clutch and heat transfer, exhaust.
Scary stuff anyway