0W-40 is the regular oil. The older high-revving M-cars use 10W-60... not so sure about the new ones.The BMW LL-01 5W-30 is "almost" a 5W-40. It's high temperature viscosity is higher than the minimum for an SAE 5W-30. They do make an LL-01 0W-40, It's used in M cars. I think Castrol makes a LL-01 certified 0W40 and it's sold at Walmart, and it's cheap. Not all Castrol's are BMW LL certified, so you need to read the back of the jug.
I think the turbo-charged M's use LL-01 0W-40. My E46 M3 required 10W-60. The E39 M5 could use either 5W-30 or 10W-60.0W-40 is the regular oil. The older high-revving M-cars use 10W-60... not so sure about the new ones.
It's the same reason the S85 engines were seeing so many rod bearing failures. 10W-60 is like really thick maple syrup... molasses, even. When you have an engine with ridiculously tight tolerances and manufactured with extreme precision, the oil needs to be a little thinner than molasses before you can start driving it like it needs to be driven. A slew of people bought those high-revving M cars and drove them like Toyotas or Hondas... 4,000 RPM right off the bat.I think the turbo-charged M's use LL-01 0W-40. My E46 M3 required 10W-60. The E39 M5 could use either 5W-30 or 10W-60.
The very early E46 M3's (model year 2001, produced from maybe March through September of 2001) came with 5W-30. But, after they were blowing up left and right, they recalled them and switched to 10W-60. The MY 2002's came with 10W-60, but they were blowing up even more than the MY 2001's. It took a while for BMW to get this straight.