Abstract: A fluid cooling device in the form of a modular unit has a motor which drives a ventilator wheel and a hydraulic pump which takes fluid from an oil reservoir and delivers it to a hydraulic work circuit. The circuit heats the fluid and sends it to a heat exchanger from which the fluid returns, cooled, to the oil reservoir. The oil reservoir, being shaped like a trough and surrounding at least part of the motor and the hydraulic pump and having high walls in the manner of a half-shell, results in a relatively high-volume oil reservoir with is a part of the fluid cooling device with a compact, space-saving structure by at least partially containing parts of the fluid cooling device to save space.