I am coming up on my oil change on my Hemi. It will have 90000 at the oil change interval. I go 10000 miles between oil changes with Mobile 1 5W20 and my analysis on it says that mileage is just fine. I keep seeing Mobile 1 in a 0W20 weight that says increases fuel mileage. I don’t understand how it will save mileage because the only difference is at start up and at temp it is at a 20wt. Can anybody explain the theory and if I should just stick with what I have been using or give the 0W20 a shot.

Ronnie