A rotary valve comprising a housing with a valve chamber, wherein the valve chamber has at least one inlet and at least one outlet, wherein the inlet and/or the outlet are at least partially closable, as required, by a valve body which is rotatable about an axis and is arranged in the valve chamber, wherein, on that side of the housing facing the valve body, the inlet and/or the outlet is enclosed by a sliding seal, and wherein the sliding seal bears sealingly, under elastic preload, against that surface of the valve body facing the housing.