Operating fluid container made of thermoplastic for a motor vehicle, with the following features: the operating fluid container has two openings in opposite container walls of the operating fluid container, and a stiffening element extending through both openings; and two stiffening element ends engage behind the container walls from the outside, such that the stiffening element counteracts a deformation caused by internal pressure of the operating fluid container, wherein the operating fluid container is characterized by the following features: a stabilizing element is arranged between at least one stiffening element end and a container wall; the stabilizing element has a through-opening through which the stiffening element extends; the stabilizing element has a first and a second thermoplastic; and the stabilizing element is welded to a container wall.