I had the exact same problem on my 855T5A (72,000km then), and mine took a while to figure out.

Some time after an oil n filter change, i began noticing little pools of oil appeared under the car overnite, later i narrowed the occurence down to it "leaking" only after a hard drive. Much later, after a hard(er) drive on the highway i noticed engine oil all over the top of the engine. but on all occassions i checked the oil level to make sure it was sufficient, and it was.

after a while i began to suspect overfill, with the oil spurting out of the dipstick funnel. if i recall right, the dipstick was showing some half cm above the max mark. next service, i replaced the engine oil and ENSURED the mechanic filled only to the halfway mark. (them mechanics seem to always think the oil level will go down a lot once the engine's started and they "compensate" by overfilling) no more problem ever since.

hopefully this is the cause of your oil leak cos the solution would be so simple.

rgds

jeff

95 855T5A, SAM chip, IPD swaybars, full S/sprint exos, Bilsteins

Wild-ass-guess, but here goes..

There should be some one-way valves in the crankcase ventilation tubing, so it will suck the vapors directly into the intake manifold when not under boost, but the valve closes when under boost and the vapors are redirected to the turbo intake side (still a little pressure-drop).

If the valve from the intake manifold is broken (blown or something), then the intake boost pressure will probably pressurize the crankcase..

Hope this helps..

Bye, arno.

Have you inspected all the vacuum hoses and other PCV related hoses? Take a good look at the vacuum hose from where it connects to the intake manifold behind the PS pump at one end and where it exits near the turbo inlet (intake air hose by a lower sensor) at the other end. If that hose leaks, you'll build too much boost and that could contribute to your problems.