Many years ago, my father was a long haul truck driver. He made trips across the northern states and Canada. Back then truckers carried a home made pan fashioned from a piece of tin or sheet metal, which was hammered into a shallow bowl.
In the morning, he would light a small fire in the pan and place it directly under the trucks oil pan. After 10 mins or so, the oil was warm enough to flow freely when he cranked the engine.
He told me that was only good to -30. Any colder than -30 and he would just leave the truck running all night. Diesel was insanely cheap back then and the cost of the fuel used over night was better than lost time the next day trying to get his rig running.
Good old days.
