Electrically operated heaters are often available as optional equipment on cars and light trucks. The heater may warm coolant with a heating element located in a coolant hose or in the engine block, or the heater may be located in a position that warms the engine oil.
Engine heaters help to provide easier starting in extremely cold temperatures.
The engine heater should be checked every fall to make sure that the heating element still works. With the engine cold and not running, plug the heater into an outlet. Wait several minutes and feel the location of the heater. It should feel warm to the touch. You may have to wait a little longer to feel the heat from an engine oil heater; it depends on the location and the heating ability of the heater's element. Replace the heater if bad