Abstract: In an oil reservoir tank having a tank body and a tank cover, an air/oil separator includes a filter media pack, arranged radially symmetrically about an axis, a bottom end cap secured to one end of the filter media pack, and a top end cap and flange member. The top end cap and flange member is made of a moldable material and has a top end cap portion and a flange portion. The other end of the filter media pack is embedded in top end cap portion. The flange portion extends radially outwardly from the axis for mounting the separator between the tank body and the tank cover. The top end cap and flange member is formed of a sealing material. The top end cap and flange member is a single unitary member forming both flange and the end cap, which eliminates separate flange and trough members which must be welded or brazed together. In addition the flange portion of the top end cap and flange member eliminates the need for additional separate sealing members, such as O-rings.