A heat exchanger for cooling a component is coupled with a cowl at least partially surrounding the component. The cowl defines a cowl plenum and a peripheral gap for receiving the heat exchanger. The heat exchanger includes a housing defining a heat exchange plenum for receiving a cool fluid stream and a plurality of heat exchange tubes passing through the heat exchange plenum for receiving a hot fluid stream. A discharge manifold defines a discharge plenum that provides fluid communication between the heat exchange plenum and the cowl plenum through a fluid outlet. In addition, an impingement baffle at least partially defines the discharge manifold and defines a plurality of cooling holes for impinging cooling air on the component proximate the heat exchanger.