Oil filler cap for combustion engine

To fix the centering component (12) onto the fastening section (11), a holding clip (20) is fitted to it (11). The clip has an annular opening (21) with fastening lobes (22) projecting inwardly and angled with respect to the base (5). These grip the fastening section in the manner of a spire clip. The centering component has a drip projection (24) directed away from the base. The inner circumferential surface of the centering component makes area contact with the fastening section. Its outer circumference (14') makes area contact with the inner surface (19) of the support (1B), against which it rests.