As an example, this oil seal has a part number that corresponds to a Shaft Size of 3”, a Bore Size of 4”, a Width Size of 0.625”, a Style of TB2, and is made of Viton material. Conversely, the same size oil seal in Metric has a Shaft Size of 76.20 mm, a Bore Size of 101.60 mm, and a Width Size of 15.88 mm.
Unthinkable in the list of seals are oil seals, which provide a seal against splashing oil. The most important oil seals are used for rotating shafts and valve stem seals. Oil seals are intentionally never completely sealed to lubricate the seals and prevent wear.
Lubricant can be retained in the space between the main lip and the minor lip.
Selecting the Right Spark Plugs for Motor Vehicles
Smear a little gasket sealant round the cover flange and fit the new gasket to it. Make sure it is flat and straight.
NBR, also known as nitrile rubber or nitrile, is the most popular material for an oil seal because of its good resistance to many oils and greases, such as mineral grease and hydraulic oil. Depending on their composition, synthetic oils and greases, such as those based on glycol, can damage NBR rubber materials. Depending on the amount of glycol, a PTFE lip seal may be the best choice. NBR is also unable to cope with contact with acids and solvents. The rubber is suitable for oil and grease at temperatures from -35 °C to 100 °C.

Outer case
In addition to these standardised types, the following special types are also available: