I'll tell you what...I live in northern minnesota and it is below the freezing mark every day, alot of the time below zero. I have two motors that do this same thing. In the heated garage, the engines will run great, with an os 8 glowplugg and 15% nitro fuel. Outside, in the cold. I have to use 30% heli fuel along with the same plugg. I was told by the techs at horizon, ( you have to make sure the head stays at a certain temp, or the motor WILL die.) I do most of my flying in the winter and can assure you, this approach works.