A radiator with a fan is arranged at a forward tilt under the footrest floor part of a cab floor of a cab-over-engine vehicle. The fan confronts the front of the engine. The fan is connected with the radiator through an air duct, a central axis of the air duct rises rearwardly. The fan has at its center a boss shaped into a truncated cone, the extremity of each of the blades in its longitudinal direction being parallel to the axis of the boss. The air duct has one opening end shaped into a cylinder which partially covers the blades of the fan.