Just got to think this morning as it was -23C and I was starting the car with the Castrol 10-60 that's the only factory recommended grade to be used with BMW M models....
As it is a 10W, what M3 owner's supposed to use when the temperature dips below -25C? eg. Montreal frequently dips below this...or many parts of MN, ND, etc... Is there another factory recommended grade? Anyone know?