Abstract: A hydrostatic fan drive for internal combustion engines is disclosed, having a primary unit that can be driven by the internal combustion engine, and having a fan motor by means of which a blower fan can be driven. A hydraulic reservoir is disposed at a high-pressure line connecting the primary unit to the fan motor. A hybrid fan drive for internal combustion engines is thus provided, allowing fan operation even if the internal combustion engine is switched off. An increased maximal available power of the internal combustion engine is available in transition, despite the fan operation, because the fan motor can be supplied with pressurized media by the hydraulic reservoir in such cases (in transition).