Because the manufactures usually specify 10w40 or 20w50.quote:
Originally posted by JonS:
Why are there no 15w-40 MC oils? Is this telling us something? If 15w-40 is better than 10w-40 (less vis improvers) Why are ther so many 10w-40's?
I've used Delvac 15W-40 in motorcycles since the 1980s, well before using 15W-40 in gas engines became a fad.quote:
Originally posted by JonS:
Why are there no 15w-40 MC oils? Is this telling us something? If 15w-40 is better than 10w-40 (less vis improvers) Why are there so many 10w-40's?