An automotive headlamp assembly having a closed-loop cooling circuit. The headlamp assembly includes a housing cooperating with a transparent lens cover to define a chamber. At least one light source is located within the chamber. The cooling circuit has at least one cold plate thermally coupled to the light source. A radiator is fluidly coupled to the cold plate by a plurality of tubes. The tubes are oriented at least partially upwardly and configured to circulate a fluid through the cooling circuit as a result of heating and cooling of the fluid therein.