A gas cooler and heat exchanger assembly comprises a gas cooler, including a cylindrical inlet header and a cylindrical outlet header, and a heat exchanger, including a first tank and a second tank, with at least a portion of each of the tanks being cylindrical and being an extension of and integral with each of the associated and aligned headers. In the first embodiment, the entirety of each of the tanks is cylindrical in shape and extends from the associated header. Each of the tanks is bisected thus defining a semi-cylindrical hot chamber and a semi-cylindrical cool chamber. In the second embodiment, only the cylindrical hot chamber of each of the tanks is cylindrical in shape and extends from the associated header. An additional box-shaped structure defines a box-shaped cool chamber disposed along and inwardly of each of the cylindrical hot chambers.