A cooling circuit for the thermal engine of an automotive vehicle includes a main loop that includes a first exchanger for collecting the heat from a first heat source, a first radiator and a pump connected in series by ducts for the circulation of a cooling liquid, the temperature of the cooling liquid being kept under normal operation conditions at a temperature lower than or equal to a predetermined threshold value. The cooling circuit includes a first bypass of the main loop in parallel relative to said first radiator, the first bypass including sequentially, in the circulation direction of the cooling liquid, a second exchanger for collecting the heat from a second heat source and a second radiator connected in series by ducts for the circulation of the cooling liquid, the temperature of said cooling liquid at the outlet of said second exchanger being set, under normal operation conditions, at a temperature higher than or equal to the predetermined threshold value.