A float wall heat shield for use on an endwall of a stator vane used in a gas turbine engine. The heat shield includes an attachment extending from a center of the heat shield to secure the shield to the vane. A plurality of ribs formed on the inside surface of the shield forms cooling channels extending in the streamwise direction. The leading edge of the shield curves downward over the leading edge of the endwall and forms a cooling air inlet. The trailing edge of the shield forms a cooling air exit extending in a straight direction to provide purge air for a rim cavity of an adjacent rotor blade assembly. The heat shield includes pressure and suction sides that conform to an outline of the airfoil of adjacent vanes, and forms cooling air exit gaps so that the cooling air passing through the channels can discharge to prevent inflow of the hot gas flow. The heat shield eliminates the need for film cooling holes.