I think that's part of the point though. BMW's goal was to design a specification that lubricated the engine efficiently in all parts of the world year round.
Originally Posted by bimmernut3
It will work fine year round unless you live in Fargo.
I highly doubt 0w and 5w were chosen for fuel efficiency though. For the most part a 0w-30 and a 10w-30 will have similar viscosities at operating temperature. 0w/5w/10w will only make a difference at temperatures below freezing. So there really is little disadvantage to using a 0w-30 or a 0w-40 over a 10w-whatever. It's the other end of the spectrum that will have a larger impact on fuel economy - which is why many cars have 5w-20 as the recommended oil. I've even heard of a few cases where 5w-20 is recommended in the US while the RoW gets a Xw-30 recommendation.
Would most be fine with a 10w-30? Yes. But unless you get a super deal on it, I see no reason to use it.
Last edited by TerraPhantm; 10-11-2012 at 02:32 AM.