A venting and/or air admission valve for an operating fluid reservoir having the following features: - the venting and/or air admission valve comprises a hollow valve housing, which can be fastened in an interior of an operating fluid reservoir; - the valve housing comprises at least one communication opening for fluid exchange between a valve housing interior and the interior of the operating fluid reservoir; - the valve housing comprises a ventilation opening for gas exchange between the valve housing interior and a ventilation line; - the venting and/or air admission valve comprises a valve body arranged in the valve housing interior; - in the installed position of the venting and/or air admission valve in the operating fluid reservoir, the valve body is at a distance from the ventilation opening when an operating fluid level within the interior of the operating fluid reservoir is below a shutoff level, with the result that the valve housing interior and the ventilation line are in fluid communication; and - in the installed position of the venting and/or air admission valve in the operating fluid reservoir, the valve body is subject to a lift from the operating fluid in the valve housing interior such that the valve body closes the ventilation opening when an operating fluid level within the interior of the operating fluid reservoir is above the shutoff level, with the result that the valve housing interior and the ventilation line are not in fluid communication, wherein the venting and/or air admission valve is characterized by the following features: - the venting and/or air admission valve comprises an adapter (31, 32), which can be fastened on an inner face of an operating fluid reservoir wall; and - the valve housing can be fastened on the adapter (31, 32) in such a way that the adapter (31, 32) is arranged between the operating fluid reservoir wall and the valve housing. - the venting and/or air admission valve comprises a hollow valve housing, which can be fastened in an interior of an operating fluid reservoir; - the valve housing comprises at least one communication opening for fluid exchange between a valve housing interior and the interior of the operating fluid reservoir; - the valve housing comprises a ventilation opening for gas exchange between the valve housing interior and a ventilation line; - the venting and/or air admission valve comprises a valve body arranged in the valve housing interior; - in the installed position of the venting and/or air admission valve in the operating fluid reservoir, the valve body is at a distance from the ventilation opening when an operating fluid level within the interior of the operating fluid reservoir is below a shutoff level, with the result that the valve housing interior and the ventilation line are in fluid communication; and - in the installed position of the venting and/or air admission valve in the operating fluid reservoir, the valve body is subject to a lift from the operating fluid in the valve housing interior such that the valve body closes the ventilation opening when an operating fluid level within the interior of the operating fluid reservoir is above the shutoff level, with the result that the valve housing interior and the ventilation line are not in fluid communication, - the venting and/or air admission valve comprises an adapter (31, 32), which can be fastened on an inner face of an operating fluid reservoir wall; and - the valve housing can be fastened on the adapter (31, 32) in such a way that the adapter (31, 32) is arranged between the operating fluid reservoir wall and the valve housing.