Article originally published on Noria.com
Petroleum base mineral oils have some limitations, depending upon the type of base stock used, the level of additives blended and the operating conditions encountered. The main service difficulties within mineral oils are:
- The presence of waxes, which can lead to poor lubrication at low temperature.
Poor oxidation stability at continuously high temperatures, which can lead to sludge and acid buildup.
The dependence of viscosity on temperature, which can cause the base oil to thin excessively at high temperature.
A natural high temperature application limit of about 320°C (608°F), above which the base oil decomposes and begins to coke (turns to a sooty substance). Under severe operating conditions, such as extremely high temperatures, or in very cold operating climates, the difficulties noted above are important factors in the selection of lubricants. Very often, the only solution is the selection of a synthetic oil.