Snow groomer with a propulsion system in which an endothermic engine is accommodated in an engine compartment adjacent to the cabin and provided with a liquid cooling system provided with a radiator coupled to a fan configured to suck an air flow into the engine compartment. An electronic control unit controls the on/off cycle of the fan based on a signal T.sub.Water that is a function of the measured temperature of the cooling liquid in the radiator and a reference signal T.sub.Water_ref representing a target temperature. The control unit processes a further control signal Tc relating to the amount of the heat flow from the engine to the cabin and compares the control signal Tc with a reference signal Tcref to control the start-up of the fan to generate the intake of air at room temperature into the engine compartment and the expulsion of hot air from the engine compartment.