Definitely option B. the car will blow smoke after long periods of idling...good example is a long red light, and that's only some of the time. It has never smoked when the car is fired up in mornings after sitting all night. If my wife hops in fires the car up and goes, you never see it smoke. But, I've sat in the driveway idling for long periods of time, then stab the gas and white smoke rolls out the exhaust. I can also smell oil burning from the leaky valve covers dripping on the exhaust.

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2004 545i