A control valve for adjusting fluid flow has a cylindrical housing bushing with a first and a second flow opening. A control bushing is arranged coaxially in the housing bushing and adjustable between control positions opening and/or closing the flow openings. A first spacer disk and a second spacer disk are arranged axially spaced apart at the housing bushing and surround the housing bushing. At least the first spacer disk is arranged eccentrically at the housing bushing by eccentric displacement relative to a longitudinal axis of the control valve. A first side of the housing bushing has a larger radial spacing relative to an outer rim of the first spacer disk than a second side of the housing bushing. At least one of the first and second flow openings is arranged at the first side of the housing bushing. A cooling system is provided with such a control valve.