The invention relates to an operating fluid tank (1) for a motor vehicle, comprising a tank body which is composed of two mutually complementary, injection-molded shells (2) which are made of thermoplastic material and which are welded circumferentially to one another to form a substantially closed hollow body, wherein at least one shell (2a, 2b) is formed at least in certain regions from thermoplastic materials of differing strength and/or elasticity, wherein at least one partial region is formed from a thermoplastic material which is elastically deformable, and wherein the shell (2a, 2b) has been obtained by a co-injection process during injection molding.