Sorry Pauly, over 27,000 combined miles on sleds in my group over the last 5 years. No problems at all, none. If an oil meets or exceeds the highest standards in the oil industry, which Citgo Sea and Snow does, I will use it. Especially when it is 12-15 a gallon. If you want to keep using Amsoil, hey, that is great! By the way, you are right, the manufacturer's say to use full synthetic, they also say to use THEIR full synthetic.