This may or may not be related - not sure. My 89 760 B230 turbo has had what I thought was pretty bad crankcase pressure, pushing oil past the cap and sometimes out the dipstick. It is a worn engine - not really sure how many miles. I had replaced the O ring on the cap, replaced the breather box and cleaned all the hoses and orifices, and it still had the pressure prob.

About 3 weeks back I was on a trip, and it lost all it's umoopth - bogging down if you gave it too much gas - just like it had a hole in one of the turbo hoses. I nursed it back home (well over 100 miles) and pulled all the hoses to check for an air leak. In doing so I found the CBV valve just barely on - the bolts about to come out. The gasket was gone. I pulled it off, cleaned everything up good, and made me a gasket.

Car now runs right, but the big thing I have noted is my valve cover does not have an oil streak down it. Oil consumption is down too. As I said, this does not seem to be related for some reason, but I thought I should share.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (158K), '94 940T (240K), 85 245 (219K)