Cooling louvre, in particular for an automobile for controlled ventilation of the engine, with a frame in which at least two discs are rotatably mounted in such a way that they can be moved by a completely closed position (approx. 0°), in which the louvre blades of the louvres are arranged substantially parallel to the frame plane and either partially overlap or lie close together in the adjacent area, so that the frame opening is substantially closed to the air flow, into an open position (approx. 90°), in which the blades of the louvres are arranged essentially perpendicular to the frame plane, so that the frame opening is essentially maximally open for the air flow, can be swivelled, whereby the discs are mounted in bearings on two opposite sides of the frame, wherein a motor is provided in or on the frame on a motor side of the frame, which drives a single slat, and wherein a coupling element is provided on the same motor side of the frame, which synchronously transmits the rotation of the driven slat to the other slats (8, 10-11), and wherein a locking element (18-21, 60, 63) is provided for each slat on the mounting side of the frame facing away from the motor side of the frame in the region of the mounting of the slats provided there, and wherein the locking elements (18-21, 60, 63) are coupled directly or indirectly in such a way that, if at least one of the locking elements (18-21, 60, 63) does not rotate synchronously with all the other locking elements (18-21, 60, 63), the rotational movement of the locking elements (18-21, 60, 63) is blocked in at least one direction, preferably in a force-locking and/or form-locking manner characterised in that the locking elements are designed as locking discs (18-21, 60, 63) or as locking elements (60, 63) with at least one engagement pin that is radially offset with respect to the axis of rotation of the discs, wherein the engagement pin extends parallel to the axis of rotation of the discs and performs an arcuate movement synchronously with the disc when the disc rotates, and wherein the engagement pins of all locking elements are coupled via a common locking rod extending perpendicular to the axis of the discs, and wherein the locking discs have a shape which, if at least one of the locking discs does not rotate synchronously with all the other locking discs, blocks the rotary movement of the locking discs in a force-locking and/or form-locking manner. with a frame in which at least two discs are rotatably mounted in such a way that they can be moved by a completely closed position (approx. 0°), in which the louvre blades of the louvres are arranged substantially parallel to the frame plane and either partially overlap or lie close together in the adjacent area, so that the frame opening is substantially closed to the air flow, into an open position (approx. 90°), in which the blades of the louvres are arranged essentially perpendicular to the frame plane, so that the frame opening is essentially maximally open for the air flow, can be swivelled, whereby the discs are mounted in bearings on two opposite sides of the frame, wherein a motor is provided in or on the frame on a motor side of the frame, which drives a single slat, and wherein a coupling element is provided on the same motor side of the frame, which synchronously transmits the rotation of the driven slat to the other slats (8, 10-11), and wherein a locking element (18-21, 60, 63) is provided for each slat on the mounting side of the frame facing away from the motor side of the frame in the region of the mounting of the slats provided there, and wherein the locking elements (18-21, 60, 63) are coupled directly or indirectly in such a way that, if at least one of the locking elements (18-21, 60, 63) does not rotate synchronously with all the other locking elements (18-21, 60, 63), the rotational movement of the locking elements (18-21, 60, 63) is blocked in at least one direction, preferably in a force-locking and/or form-locking manner characterised in that the locking elements are designed as locking discs (18-21, 60, 63) or as locking elements (60, 63) with at least one engagement pin that is radially offset with respect to the axis of rotation of the discs, wherein the engagement pin extends parallel to the axis of rotation of the discs and performs an arcuate movement synchronously with the disc when the disc rotates, and wherein the engagement pins of all locking elements are coupled via a common locking rod extending perpendicular to the axis of the discs, and wherein the locking discs have a shape which, if at least one of the locking discs does not rotate synchronously with all the other locking discs, blocks the rotary movement of the locking discs in a force-locking and/or form-locking manner.