A cooling circuit comprises a regulating valve, the moving shutoff means of which is actuated by an electric motor the feed current of which is subjected to the action of an electronic control system sensitive to various operating parameters of the internal combustion engine. A safety thermostatic wax capsule is located in a chamber of the valve so as to act on the moving shutoff means so that hot cooling liquid coming from the internal combustion engine is conveyed at least for the most part, towards a radiator only in the case where the temperature of the cooling liquid in the chamber exceeds by a predetermined amount, the temperature for which the electronic system is set.