Originally Posted By: Oil Changer
Convenient for you that you can't prove anything you wrote.
Originally Posted By: fredfactory
Fram Ultra beats any M1 oil filter in ISO 4548-12 efficiency and capacity testing.
M1 0w-40 is a thick oil that will return about 1%-2% less gas mileage compared to using a good synthetic SN-GF5 5w-30 or M1 0w-30 oils. For that car, I'd use Castrol Edge Extend Perf 5w-30, M1 0w-30, or M1 Extend Perf 5w-30 for plenty of wear-deposits protection without the worse gas mileage you will get with the thicker 0w-40.
Troller from Michigan!!! Mad about Detroit maybe?
Proof comes in the form 4548-12 testing published, and many, many engineering studies that show more highly viscous oil eats more fuel, can vary by engine, so its always been in the range of 1% to 2%. Nice try trolling. Better luck next time.