The present invention relates to a multifunctional module for an internal-combustion engine, forming a structural assembly and incorporating the functions of cooling the exhaust gases, regulating the re-injection of the exhaust gases and regulating, at least in part, the circulation flows in the cooling circuit of said engine, said structural assembly being in the form of a constructional and functional unit intended to be fitted to the engine block and incorporating, on the one hand, at least a portion of an exhaust gas recirculation circuit and a heat exchanger for cooling said gases and, on the other hand, at least a portion of the engine cooling circuit, with at least the water-outlet housing, multifunctional module characterised in that the heat exchanger has a tank arranged in the region of an end of the constructional and functional unit and made from a synthetic thermoplastic material.