Thanks for the mini-education, Kevin. I took a look at Castrol Syntec. The 0W30, 5W30, and 10W30 meet ALL the GF-3 requirements. 10W40 lists GF-2 (but does not say all). 5W50 meets the "engine protection requirements of ILSAC GF-3 for API Certified Gasoline En... Login to read more.