Disclosed is a fluid friction clutch, preferably for driving the fan in an automotive cooling system, comprising a driven disk member; a drivable housing member surrounding the driven disk member in such a manner as to provide a working chamber therebetween for receiving a fluid capable of transmitting rotational force between the driven disk member and the housing member; a reservoir separate from the working chamber for containing the fluid; a selectively openable and closable inlet orifice providing fluid communication between the reservoir and the working chamber; a return conduit providing fluid communication between the working chamber and the reservoir; and a supplemental disk member rotatable with the driven disk member and positioned within the reservoir so as to be wetted by the fluid at least when the fluid friction clutch is at rest.