Coolant Heater

[Geoff Winnington-Ball (RIP)]

This likely stemmed from experience in the Korean War where vehicles froze solid in intense cold unless they were started and warmed every couple of hours. It makes sense. The Germans had the same experience in Russia during the endless months of the winter campaigns; there are many stories of having to build fires underneath the engines of vehicles and aircraft alike, just to enable them to be started. In the 40's and early 50's, the answer was to dilute the oil with diesel fuel, but that obviously wasn't a successful remedy, especially in terms of engine longevity.

I'll look into this some more.