OK. SOMEONE PLEASE ANSWER THIS QUESTION: I know, I know, that Castrol Syntec is not a "True" synthetic oil. However, I have used Castrol GTX before I became a Mobil 1 and Amsoil boy. I know the story with regards to the suit filed by Mobil. However, I would like to know. WOULD SOMEONE PLEASE GIVE ME A SCIENTIFIC REASON WHY NOT TO USE CASTROL SYNTEC. I was thinking about the 5w50 or 10w40 for summer. Has anyone ever done a Virgin sample on this oil? How does the numbers compare to Mobil 1 or any other off the shelf motor oil? I really don't care what anyone wants to call Syntec, **** if they found out that Olive Oil held better numbers I would use it. So please, hold the PAO bias, and give me a reason why this oil wouldn't perform well in my truck.