In the summer time, why would you use 0W30? I've never seen people here say that they use 5W20, but 5W20 is a thinner oil at operating temperature. 0W30 has the same viscosity as 5W30 or 10W30 at operating temperature, while 5W20 is thinner than all those. All Ford fuel injected vehicles changed to 5W20 from '01, even in the new 3L Duratec equipped vehicles. Maybe we should run 5W20 if we're just after a lower viscosity?
