Abstract: A self-contained portable heating system for preheating the coolant in an internal combustion engine to aid in cold weather starting. The heater and associated fuel supply are mounted on a portable cart, and connected to an engine to be preheated by hand operated quick disconnect fittings.The heating system incorporates thermal powered automatic controls to control the coolant temperature, and allow the heater to automatically start at a prescribed time. A pressurized gas burner having a mixing nozzle and baffle system, provides a clean burning stable heat source, even in windy or gusty conditions.