Abstract: The oil side-flow cleaning device includes a heating unit (11) installed between the oil tank and the filter unit (10) so that, when the oil temperature is below a defined limit value, oil flows through the filter unit (10) in such a way as to bypass the filtering function and is heated; and so that, when the oil temperature is above the defined limit, oil flows through the filter unit (10) so as to be subjected to the oil filtering function. In addition or as an alternative, the oil side-flow cleaning device comprises a backflush unit including a backflush collecting tank (17) and a backflush nozzle (18), wherein, when the device is in backflush mode, oil flows through the filter medium (16) in a second, opposite direction as a function of the position of the backflush nozzle (18) relative to the filter medium (16).