yep i read the same s***,thats why i stopped using it.i did a lot of research before i started using Amsoil.goldstar said:Since this is a thread about synthetic oil, I have to mention that Castrol Syntec is NOT a true synthetic oil although, for reasons I won't go into now, it can be marketed as one.
Of the five classes of oil base stocks recognized by the American Petroleum Institute (API), Groups I-III are classified as mineral oil base stocks and Groups IV and V are recognized as synthetic base stocks.
Castrol Syntec is derived from a hydrocracked Group III petroleum-based stock, while Amsoil and Mobil 1 are derived from the Group IV, polyalphaolefin (PAO) synthetic base stock and Red Line is formulated from the Group V Polyol ester synthetic base stock.
goldstar said:Since this is a thread about synthetic oil, I have to mention that Castrol Syntec is NOT a true synthetic oil although, for reasons I won't go into now, it can be marketed as one.
Of the five classes of oil base stocks recognized by the American Petroleum Institute (API), Groups I-III are classified as mineral oil base stocks and Groups IV and V are recognized as synthetic base stocks.
Castrol Syntec is derived from a hydrocracked Group III petroleum-based stock, while Amsoil and Mobil 1 are derived from the Group IV, polyalphaolefin (PAO) synthetic base stock and Red Line is formulated from the Group V Polyol ester synthetic base stock.
urbanbiker said:goldstar - castrol rates the 10w30 as well as 5w30 as group IV on their website here is the link
http://www.castrol.com/castrol/genericarticle.do?categoryId=82915470&contentId=6006933
either things have changed or you got some wong information from someone
matt