I'm not sure who invented this in the first place but I have read that Germans learned it from Russians.
Ok, "Kaltstart" i.e. 15% gasoline in engine oil which vaporized quite quickly when the engine was running. However, it was prohibited to put any load on the engine during warm-up or the engine would seize-up. Once Rudel was in such a hurry that he didn't have time to wait sufficiently and he ended up ditching a FW190 due to engine failure. I'm not sure who invented this in the first place but I have read that Germans learned it from Russians.-C+