I never had a problem with this car until the engine seized and died one day. I had the car towed to BMW and a few days later they said I had sludge and that caused the problem which will cost around $7,000 to fix. They said that I was overdue for my initial oil change and although I had it changed twice since the problem occurred I was responsible even though it is still under warrenty. BMW North America has been no help in trying to resolve this problem and I have been without the car for a month while we argue back and forth.