Diesel oil, however, is a little different as it's engineered to work best in an engine that burns diesel fuel. The biggest differentiator is that it is much thicker than traditional oil ...

Ford has supplied an SAE viscosity grade chart for the 6.7 Power ... Ford recommends Motorcraft 0W-40 diesel oil. For severe duty uses, the best oil for your Ford 6.7 Power Stroke is Motorcraft ...