A filtering system (9) includes a filter head (12) and a replaceable filter (10). The filter head (12) has a feed line (66) and discharge line (62). The replaceable filter (10) is removable and replaceably mounted onto the filter head (12) by a rotational and/or plug connection (15) and includes a housing (17) with at least one inlet (26) for oil to be filtered and at least one outlet (28). The inlet (26) communicates with the feed line (66). The outlet (28) communicates with the discharge line (62). The housing (17) has a filtering element (34) that sealingly separates the inlet (26) from the outlet (28). The filter head (12) includes an auxiliary oil line (60). The replaceable filter (10) has a flow control element (53) that automatically closes or releases the auxiliary oil line (60) dependent on an operation and/or assembly condition.