A fluid friction clutch includes a drivable housing having a working chamber and a reservoir, at least one opening between the reservoir and the working chamber configured to provide fluid communication between the reservoir and the working chamber, a driven disk supported for rotation in the working chamber, and a rotor mounted in the reservoir and rotatably coupled to the driven disk for rotation about an axis of rotation, the rotor having a plurality of arms, separated by a plurality of gaps, projecting away from its axis of rotation.