Impala64ssa wrote: “The old Hudson Hornets, when temps got that cold they’d recommend adding a pint of kerosene to the crankcase to thin out the oil. Of course you had to remember to change the oil to a thicker viscosity as soon as the weather got warmer. These were the days before multi viscosity oils.”
The Luftwaffe on the Eastern Front in the winter would put a small amount of gasoline in the crankcase. Or, so a former Luftwaffe pilot told me. Also, the tires would freeze to the ground.
The Germans must have learned that from the Soviets who did that to their tank engines.