Abstract: A radiator for dissipating heat transferred from a liquid cooling medium contained therein and that circulates by convection around and absorbs heat energy from an internal heat source. The radiator has a housing that contains the liquid cooling medium and that has two upright end walls and four finned rectangular side walls that define a prism of advantageous aerodynamic form supported with its axis horizontal. The four side walls of the prism intersect in a horizontal plane and a vertical plane, both of which form diagonal planes of the prism. The finned side walls are adapted to transfer heat energy to the surrounding atmosphere and to establish convective flow in paths with minimum flow resistance, that extend upwardly from the intersection of the two lower side walls (i.e., at the nose of the aerodynamic form) at the bottom of the housing and across the entire surface area of the finned side walls to absorb heat energy transmitted to the finned walls by the liquid medium.