I bought my 528xi in July, and have steadily had to add a quart about once a month (approx every 1500 miles). Had it in for an oil change, and the dealership said they saw no leaks. I have no leaks under the car, and the exhaust tips show no sign of burned oil exhaust. WTF? I've never owner a car, BMW or otherwise, that required that much additional oil between changes.