Hello Brickheads:

The inevitable has occured. The rear main seal in my 1996 Volvo 850 -non turbo (81,000 miles)is leaking oil. There is no way this should even begin to happen until way after 100,000 miles. The rate of leakage is 1 quart of oil at highway speeds 70 mph plus per 150 miles or one half quart per 2 weeks driving around city streets. I am aware that this is a common problem in the 850 due to an inferior original rear main seal which Volvo installed in this vehicle and others. After reviewing the archives in this forum, I noted references to "excessive crankcase pressure" as and additional cause of seal failure. I noticed that the engine valve cover is seeping oil also. I am saving up my pennies for the $500-$800 rear main seal an valve cover seal job and am not a happy camper. I suspect this problem is caused by multiple factors and want to repair them now.

Does anyone know the cause of this reported "excessive crankcase pressure"? I do not want to go through this expense again. Please note, I change the oil myself (and do not overfill) every three thousand miles or three months. I examine and clean the flame trap (pcv system) at every oil change. It has never been plugged.

Your in input is appreciated.

Dan