Article originally published on Noria.com
Temperature has many strange effects on lubricant states, performance and condition. Like many things in life, when it comes to lubricant temperature, there's a need for control and moderation. In other words, you can expect problems if you have too little or too much. Find the temperature sweet spot and the performance and service life of your lubricant can be extended manyfold. Of course it's all so easy to say, but in practice can be oh so difficult to do.
How cold affects lubricants
When exposed to cold temperatures, lubricants can chemically degrade, separate into phases and exhibit altered physical states.
Some examples of how cold affects lubricants include:
- Blended base oils can begin to separate into phases
- Certain additives can become insoluble, resulting in settling, flocculation and formation of deposits
- Many additives that depend on heat-induced chemical reactions fail to perform
- Oil can become too viscous to circulate and grease too stiff to feed
- Contaminants by-pass filters as thickened cold oil opens relief valves
These are only a few consequences of cold lubricants.
How heat affects lubricants
On the opposite end of the spectrum, heat can also negatively affect lubricants. Once they've exceeded their base activation temperature, lubricants will degrade (oxidize) twice as fast for every 10°C (18°F) increase in temperature.
Some problems with too much heat include:
- Accelerates additive and base oil decomposition
- Some additives will volatilize and escape into the atmosphere
- Heat collapses oil films, causing accelerated abrasion and scuffing conditions
- Hot oil shortens the life of filters and seals and accelerates corrosion
- Grease separates faster (oil from thickener) at elevated temperatures'