Rotary slide valve for a cooling circuit with a housing comprising a cylindrical inner contour, a control body which is rotatably arranged in the housing and comprises a cylindrical outer contour and at least one through-flow opening, at least one first connection opening at the housing, at least one second connection opening (30; 32) at the housing, which is arranged perpendicular to an axis of rotation of the control body and can be fluidically connected to the at least one first connection opening via the at least one through-flow opening of the control body, and at least one sealing element, which is arranged radially between the control body and a cylindrical housing inner wall surrounding the at least one second connection opening (30; 32), and comprises a base plate with an opening, which is configured to correspond to the second connection opening (30; 32) in the housing, wherein the base plate rests at least partially against the control body and comprises two axially extending side surfaces which are arranged opposite two projections which extend parallel to the axis of rotation and are configured at the cylindrical inner wall of the housing, wherein the sealing element in the unassembled state is slightly more strongly curved than the outer contour of the control body and a sealing lip extends from the base plate, which sealing lip is aligned in cross-section in a V-shape with respect to the base plate, wherein the sealing lip extends from an opening edge of the base plate bounding the opening in a preloaded manner against the cylindrical inner wall of the housing. a housing comprising a cylindrical inner contour, a control body which is rotatably arranged in the housing and comprises a cylindrical outer contour and at least one through-flow opening, at least one first connection opening at the housing, at least one second connection opening (30; 32) at the housing, which is arranged perpendicular to an axis of rotation of the control body and can be fluidically connected to the at least one first connection opening via the at least one through-flow opening of the control body, and at least one sealing element, which is arranged radially between the control body and a cylindrical housing inner wall surrounding the at least one second connection opening (30; 32), and comprises a base plate with an opening, which is configured to correspond to the second connection opening (30; 32) in the housing, wherein the base plate rests at least partially against the control body and comprises two axially extending side surfaces which are arranged opposite two projections which extend parallel to the axis of rotation and are configured at the cylindrical inner wall of the housing, wherein the sealing element in the unassembled state is slightly more strongly curved than the outer contour of the control body and a sealing lip extends from the base plate, which sealing lip is aligned in cross-section in a V-shape with respect to the base plate, wherein the sealing lip extends from an opening edge of the base plate bounding the opening in a preloaded manner against the cylindrical inner wall of the housing. the base plate rests at least partially against the control body and comprises two axially extending side surfaces which are arranged opposite two projections which extend parallel to the axis of rotation and are configured at the cylindrical inner wall of the housing, wherein the sealing element in the unassembled state is slightly more strongly curved than the outer contour of the control body and a sealing lip extends from the base plate, which sealing lip is aligned in cross-section in a V-shape with respect to the base plate, wherein the sealing lip extends from an opening edge of the base plate bounding the opening in a preloaded manner against the cylindrical inner wall of the housing.