Abstract: A gas heat exchanger for the exhaust gases of an engine including a plurality of parallel tubes that are arranged inside a casing and through which flow the gases to be cooled by heat exchange with a coolant, the coolant inlet and outlet conduits being each arranged at an opposing extremity of the casing on a single side of said casing, is disclosed. Each tube has a protuberance opposing the direction of the gases, it being possible to assemble said tubes by stacking them such that the protuberances of the respective tubes form a barrier, in the form of a deflector, intended to create a predetermined pathway guaranteeing an appropriate distribution of the coolant flow from the inlet of same to the outlet of same about the tubes and along the entire length of the exchanger. The distribution of the coolant flow passing through same is improved without the need for conventional deflectors.