I had similar symptoms with my 560SEL. The smokescreen would go away after a mile or so. The problem was ultimatly shot valve guides. What happens is as the motor warms up, the loose guides expand and seal up their fittings and the severity of the leak lessens. My car would burn about a quart of oil every 100 or so miles.

I hope yours is less involved. Mine required a valve job, and while i was there I replaced the timing chain, air intake hoses, fuel injectors, and a couple of other goodies. I gotta say, having an almost-new 560SEL is pretty sweet, not alot of non-korean cars I could have bought for the same $$$


Good Luck!