The other way oil seals work is by stopping outboard materials that can damage the machine or contaminate its lubricant. The outboard materials that the oil seal will need to stop depend on the application. However, the most common kinds are dirt, moisture, and the particles produced during manufacturing.


The rubber material used in the oil seal should be selected based on the operational temperature and substance to be sealed.
Table 5 lists the major rubber materials along with their operational temperature ranges.
Note that it is necessary to check the compatibility with fluids.
<N.B.>
Extreme pressure additives are compounds added to the lubricant. They are activated by heat and chemically react against rubber, which deteriorates rubber properties. For this reason, it is necessary to check for compatibility with rubber materials.