Thinner=more mpg. Ok, I am using high mileage because of the leaking rear main, or whatevers leaking. Ill stick with 10w-40 or 30 or whatever.

 

i think the type of oil you use should have more to do with where you live and according to the tempatures you get there. i use 5w30 in my 318 and 10w30 in my power steering pump(it use to leak ).

 

i used 10w30 all winter and my truck has not once had a slow start. and i live in MA on the coast so the wind chill can make its REALLY cold, but it doesnt affect my truck and i have plenty of oil psi. So why not just stick to 10w30? we're mostly through winter already.