5w-20 motor oil : who's using it ? ...

[SilverGlow]

Originally Posted by TheSilkySmooth

Just as an example BMW M engines have been failing running our API SL, SM 10W-30. Also Chevrolet (corvette) pulled its mobil1 recommendaion and factory fill last year due to the oil NOT staying in viscosity grade throughout the OC service interval.

NO oil stays in viscosity during it's life.

ALL oils will eventually shear down in viscosity, and often this shearing is not much because oxidation of that oil can actually thicken the oil.

Spends some time at bobistheoilguy.com and learn how oil works...otherwise your opinions are based on nothing scientific.