What do you think of using 5w 40 where 0w 40 is called for? Mercedes Benz, 2001 SLK 320.

This message has been edited. Last edited by: prtdvl,

Other then the better winter cold start flow of the 0w40, I'd say that the 2 are interchangeable. Some say that the 0w40 oils shear too much and that the 5w40 are better performing. Since most 5w40's are full synthetic, cold performance will still be very good and not worth worrying about.

I had a shearing problem with M1 0w-40 and will never use it again. Granted, it was on trips between San Diego and Phoenix in the summer, but I expected more from Mobil 1.