Liquid filter with a drain for residual liquid

A liquid filter comprising a housing with an inlet and an outlet for a liquid to be filtered, said housing having a downwardly facing, filter cartridge installation opening and a screw on cover for closing said cartridge installation opening, a filter cartridge disposed sealingly in said housing between said inlet and said outlet such that liquid from said inlet must pass through the cartridge to reach said outlet, a support tube disposed within said filter cartridge, a releasable snap connection for connecting one end of the support tube to said housing, wherein said screw-on cover is provided with a drain through which the liquid may be discharged from said housing before changing the filter cartridge, wherein said drain comprises a drain opening disposed on a central axis of said housing and cover and extending through said cover, said drain opening being sealingly closed by a valve stem which is fixedly attached to the other end of the support tube and is axially movable in said drain opening when said screw-on cover is moved.