For much of the U.S., the concept of an engine block heater is a foreign one. Even areas like the mile-high city (Denver), which faces its fair share of winter cold, are considered mild in comparison to states that border Canada. For example, in Grand Forks, Minnesota, the average temperature is below freezing for as many as 5 months each year. This kind of extreme cold is hard on an engine. (Read More at Autos.Yahoo.com)