one thing i noticed in my dads shop.every and i mean every ford we had in that had to have the valve covers pulled,were full of a whitish/brown snot on the insides of the valve covers.also this was made worse if they used pennzoil.also fords had an uncany knack in the winter of freezing up the pcv valve and would blow oil out the weakest link,which more often then not was the rear main seal.i can't say that i have ever seen a bmw with this issue but my guess would also be condensation.the thing needs to be driven.as in "the ultimate driving machine"which i really thought my 96 740il was.damn i miss that car!