There is plenty of information about how to replace engine oil seals (camshaft, intermediate shaft, crankshaft front & crankshaft rear) on Brickboard, since all seals will leak as they age, but of the seals mentioned, which ones can suddenly go bad, dumping the engine's oil and leaving you stranded by the side of the road? Or if most of the oil is in the oil pan and below the level of the crankshaft seals is catastrophic oil loss not possible. (I don't want to be stranded 100 miles from a city with my leaking front crankshaft seal going really bad - currently I'm just topping up the oil when driving around town).
Also, with the front crankshaft seal, is the only way to remove the crankshaft pulley main bolt either use an impact wrench or remove the starter motor and jam the ring gear with a screwdriver and then use socket with breaker bar on the crankshaft? Then can a (cheap) standard puller with three claws wrapped around the edge of the pulley be used to remove it or do I need some (expensive) Volvo special puller?