Copperhead
Veteran Member
The reason for the 0W20 is called for in the newer engines is because of the tight engine component tolerances. Using heavier weight oil will limit the flow to critical areas in the engine. I have two vehicles that call for 0W20 and that is all I use...in fact I only use 0W20 synthetic.
Not convinced of the closer tolerances argument. There is not that much difference in component manufacture between something like a 2016 GM 5.3L engine that 0w20 is recommended compared to a 2016 GM 6.0L that has a 5w30 recommendation. Same can be said of every engine in every brand. Not like some of their engines are done on 1960's machinery and others are done on 21st century machinery. Viscosity is not thickness, it is fluid flow resistance. You need a certain level of resistance so that oil is not squeezed out of high pressure bearings and such too quickly.