Cooling system comprising: - an engine block of an internal combustion engine, - a radiator provided with fan, - a cooling circuit in which a coolant flows, said cooling circuit comprising a first conduit that goes from the engine block to the radiator and a second conduit that goes from the radiator to the engine block, - a pump to pump the coolant in the cooling circuit towards the engine block, - an electrical motor that actuates the pump, - a first temperature sensor disposed in the first conduit at the outlet of the engine block to detect a temperature of the coolant at the outlet of the engine block, - a second temperature sensor disposed in the second conduit at the outlet of the radiator to detect a temperature of the coolant at the outlet of the radiator; - a control unit connected to the first temperature sensor, to the second temperature sensor and to the electrical motor of the pump to actuate the electrical motor of the pump according to the temperature values detected by the first temperature sensor and the second temperature sensor; characterized in that the pump is disposed in the second conduit; said control unit has a memory in which reference temperature difference values (Ta, Tb, Tc) that decrease gradually are stored, in such manner to define four intervals of decreasing temperature differences T 1 − T 2 > Ta Tb < T 1 − T 2 < Ta Tc < T 1 − T 2 < Tb T 1 − T 2 < Tc; and said control unit being configured in such manner to compare the temperature difference (T1-T2) detected by the temperature sensors with the four intervals of temperature differences stored in the memory and control said motor of the pump accordingly with four different modes; wherein said control unit has a memory in which reference temperature values are stored, comprising: a target temperature (Ttarget) set by the user for a correct operation of the internal combustion motor, a warm-up temperature (Twarmup) calculated as a percentage of the target temperature, a threshold temperature (Tthreshold) calculated as percentage of the target temperature and comprised between the warm-up temperature and the target temperature, and a maximum temperature (Tmax) higher than the target temperature; in such manner to form difference temperature intervals; said control unit being configured in such manner to compare the temperature detected by the first sensor with the difference temperature intervals stored in the memory and control said motor of the pump accordingly with said four different modes. - an engine block of an internal combustion engine, - a radiator provided with fan, - a cooling circuit in which a coolant flows, said cooling circuit comprising a first conduit that goes from the engine block to the radiator and a second conduit that goes from the radiator to the engine block, - a pump to pump the coolant in the cooling circuit towards the engine block, - an electrical motor that actuates the pump, - a first temperature sensor disposed in the first conduit at the outlet of the engine block to detect a temperature of the coolant at the outlet of the engine block, - a second temperature sensor disposed in the second conduit at the outlet of the radiator to detect a temperature of the coolant at the outlet of the radiator; - a control unit connected to the first temperature sensor, to the second temperature sensor and to the electrical motor of the pump to actuate the electrical motor of the pump according to the temperature values detected by the first temperature sensor and the second temperature sensor; characterized in that the pump is disposed in the second conduit; said control unit has a memory in which reference temperature difference values (Ta, Tb, Tc) that decrease gradually are stored, in such manner to define four intervals of decreasing temperature differences T 1 − T 2 > Ta Tb < T 1 − T 2 < Ta Tc < T 1 − T 2 < Tb T 1 − T 2 < Tc; and said control unit being configured in such manner to compare the temperature difference (T1-T2) detected by the temperature sensors with the four intervals of temperature differences stored in the memory and control said motor of the pump accordingly with four different modes; wherein said control unit has a memory in which reference temperature values are stored, comprising: a target temperature (Ttarget) set by the user for a correct operation of the internal combustion motor, a warm-up temperature (Twarmup) calculated as a percentage of the target temperature, a threshold temperature (Tthreshold) calculated as percentage of the target temperature and comprised between the warm-up temperature and the target temperature, and a maximum temperature (Tmax) higher than the target temperature; in such manner to form difference temperature intervals; said control unit being configured in such manner to compare the temperature detected by the first sensor with the difference temperature intervals stored in the memory and control said motor of the pump accordingly with said four different modes.