Closure cap, especially for closing the connection of an oil filter

Closure cap, especially for closing the screw neck of an oil filter connection in motor vehicles, wherein in the closure cap an elastically expandable nut element is arranged, which is suitable for being mounted on screw necks of different diameter, such that the nut element engages with the outer thread of a screw neck, wherein the nut element is designed in the form of a two- or multi-arm spring clip formed from a strip of resilient material which is positioned in a rotation-proof way in the closure cap and has spring arms for engagement in the thread of a screw neck, wherein on free ends of the spring arms, a portion is bent inwards for forming an inclined surface, to which a horizontal portion is connected whose free edge is inclined relative to the longitudinal axis for engagement with the thread of a screw neck.