Abstract: A heater for heating the coolant in a liquid-cooled internal combustion engine including concentrically arranged inner and outer casings defining a water chamber which communicates with the water in the engine block together with a coil in the interior of the inner casing having one end communicating with the water chamber and one end with the engine block so that fluid in the coil heated by hot gases from a propane gas burner provides circulation of heated water through the water chamber and engine block maintaining the block in a heated condition for easy starting.