is a strong suction vacuum pressure 600 the pressure 610 in the crankcase must be correspondingly higher in order to for the membrane 320 to again be lifted off from the valve seat 52 against the suction vacuum pressure acting on the outside thereof the oil separator 200 may have an overpressure valve 800 fig1 for safety reasons this overpressure valve may be configured for example as is described in de 10 2013 005 624 a1 fig8 illustrates the components of an embodiment of a filter element 100 according to the present invention this filter element 100 is configured for the crankcase ventilation system illustrated in fig1 the filter element 100 has a cover element in particular an end plate 40 this end plate 40 covers the covering surface 30 see fig3 of the filter medium 10 facing the clean fluid outlet 212 and is connected sealingly thereto so that the fluid flows through the filter medium 10 into the interior 12 of the filter medium 10 the filter element 100 is an annular coalescence element for this purpose the filter element 100 has as preferred a filter medium 10 configured as a non woven fabric that is wrapped repeatedly and thus in a plurality of layers annularly around the central tube 70 also called a support tube the central tube 70 allows for flow therethrough and therefore has openings this can be realized for example by a lattice shaped configuration u2014 as shown in fig8 u2014 by means of a perforated plate or the like the filter medium 10 is a non woven wrap for stabilization.