A cooling fan assembly operable for cooling a radiator of a vehicle includes a brushless motor and a fan element having a plurality of fan blades. The brushless motor includes a stator and a rotor. The fan element is attached at the rotor such that rotation of the rotor by the motor imparts rotation of the fan blades to enhance air flow at the radiator of the vehicle. The rotor is a molded polymeric rotor formed by injection molding a thermoplastic material. During injection molding of the rotor, a plurality of magnetic elements are at least partially overmolded by the thermoplastic material to establish the magnetic elements at the molded polymeric rotor. The rotor may have a bell-like shape, and the magnetic elements may be disposed at an inside facing surface of the rotor.