The invention relates to a device that comprises a closure element (20) that closes the opening (18) of a fuel tank (12) and that has a pot-shaped recess (22) open towards the exterior of the fuel tank (12) in which the fuel filter (24) is inserted. Said recess can be closed by way of a lid element (36) that can be detachably fastened on the closure element (20). An elastic sealing ring (46) is braced between the closure element (20) and the lid element (36) and seals off the recess (22). The closure element (20), in the zone of the sealing ring (46), has at least one opening (52) that links the recess (22) with the interior of the fuel tank (12). When the lid element (36) is fastened on the closure element (20), the sealing ring (46), starting from an undeformed basic shape, is elastically deformed in such a manner that it closes the at least one opening (52). When the lid element (36) is detached from the closure element (20), the sealing ring (36) is deformed back to its basic shape in which it releases the at least one opening (52). In this way pressure is reduced towards the interior of the fuel tank (10) when the lid element (36) is detached. |