There are 2 crank seals. The rear main is in the back and must have the transmission removed to replace it. The one sometimes changed during the timing belt service is in the front of the oil pump. That one and the 2 cam seals are usually only replaced if they are leaking, which is rare for these engines.

 

They leak past 200k or if the engine sits too long, I got burned from that. Rear main is it something that usually fails and the front is so easy to do it should be done with TB