The present invention provides a rotary axial fan and a stator fan for moving air through a heat exchanger for an internal combustion engine cooling system. The fan includes a hub and primary fan blades extending radially from the hub. An annular shroud is attached to the primary fan blades and supported coaxially with the central axis to limit the radial flow of air along the primary fan blades. A plurality of secondary fan blades are interposed between the primary fan blades and each have a first end attached to the annular shroud and terminate in a second end that is not attached to the hub. The stator fan includes a shroud with an array of stator fan blades supporting a hub for the radial axial fan. The size, orientation and material characteristics of the stator fan blades improve sound reduction and heat transfer of the rotary axial fan assembly.