My production date is 11/04.

What advantage is offered by lighter oil? Higher operating temperature?

I got the service rep to admit that this is a common problem in our climate although he was not terribly forthcoming with information. He told me that there are always a few towed vehicles sitting in the lot after a really cold weekend. I guess it's hard to get a BMW dealer to admit that "The Ultimate Driving Machine" isn't so Ultimate when you live in a cold climate!