A thermostat valve includes a housing with several cooling fluid connections, at least two hollow valve elements mounted rotatably next to one another in the housing on a common rotational shaft, each having at least one opening selectively couplable to one or more of the cooling fluid connections by way of rotation of the valve elements, and a rotational drive for a first of the valve elements can be driven rotationally in the housing, a second of the valve elements can be selectively coupled to or decoupled from the first valve element, the second valve element driven rotationally, when it is coupled to the first valve element, and a coupling element mounted axially movably on the rotational shaft, and a coupling drive by way of which the coupling element can be moved axially on the rotational shaft between a coupling position and a decoupling position.