Engine cooling system

The invention relates to the technical field of engines, and discloses an engine cooling system. The engine cooling system comprises a main cooling fan, a main radiator, a controller, a temperature sensor, a secondary cooling fan and a secondary radiator, wherein the main radiator is communicated with a water chamber of an engine; the secondary radiator is communicated with the water chamber of the engine; the secondary cooling fan is arranged on a side face of the secondary radiator; a pipeline between the secondary radiator and the water chamber of the engine is provided with a switching valve; the temperature sensor is used for detecting water outlet temperature of the water chamber of the engine and transmitting a water outlet signal to the controller; the controller receives a water temperature signal and judges whether the water outlet temperature is greater than a preset value; and if the water outlet temperature is greater than the preset value, the controller controls the switching valve to be opened and controls the secondary cooling fan to be in a working state. The heat dissipating capacity of the engine cooling system is matched with that required by the engine.