I have a 1993 850 and my rear main seal leaks. Waht can this be caused by?my car has 136K on it. The dealer wants 850 to fix it. Any thoughts on why it went and how often do they last?

Doug,

FWIW, I agree with P Dwyers comments and the price quoted is indeed to high. They remove the battery, air box and connecting air duct, then they seperate the engine from the tranny. This is nothing new to them as they have done it many times as 850s are famous for rear engine seals going. My mechanic did it in less then two hours, the part is around $30 Canadian. Interesting to note, the replacement part (OEM) had additional foam like material attached to the ring (the part is a round 5"-6" diameter rubber gasket), unlike the original. Volvo improvement?

Doug: the most common reason for the rear main seal leaking is excess crankcase pressure, the best reason to check and clean your PCV system, including the flame trap on non-turbos; also, when switching from a 'dino' oil to a synthetic (like Mobil-1 or Amsoil), the cleaning action of the synth gets rid of the crud and goop that are on the seals, and the seals leak, not because the synth caused it, they just made evident a problem that was ongoing but not visible...yet. They have to drop the tranny to get at it, but $850 sounds excessive, IMHO, even in Canadian dollars.--PD.