Quote: You may have guessed-no degree here. Tell me more about the reason that the new 5.7 Hemi calls for 5-20 instead of the 10-40 recommended by the builder of my 440. Is it the tolerances? Is this why the make-up of the synthetic can clean/loosen buildup that can lead to a leak? Is it the passage ways themselves that are too tight for the 40 weight?
I've heard that, in part, it's because of the MDS system. A heavier oil prevents the cylinder deactivation from working.
