As oil temperature decreases, viscosity increases, friction increases and excessive heat is generated. Regarding temperature, as oil temperature increases, viscosity decreases resulting in lower volumetric efficiency, overheating and wear.

“Either way, when you use an oil with an incorrect viscosity, you reduce the life of the machine-in some instances rather quickly,” Ruffin said. In today’s tighter clearance situations, oil with a viscosity that is too high can clog at or near the clearance and provide almost no protection for affected components.

Oil that’s too thin, however, can lead to insufficient oil pressure, an inconsistent lubricating film, metal-to-metal contact and wear.Ĭircumstances where a higher viscosity oil makes sense are just the opposite: high load, low speed and a higher operating/ambient temperature. A lower viscosity oil makes sense in circumstances where there is low load, high speed and a lower operating/ambient temperature. As long as they provide adequate surface coverage and separation, these oils reduce internal friction better than higher-viscosity oils. Today’s advanced machinery is trending toward much tighter clearances between components, enabling the use of lower viscosity oils. The concept can be confusing, but you can think of viscosity this way: water has a kinematic viscosity of close to zero centistokes (cSt) while something like molasses is well over 1000 cSt.” TestOil Field/Data Analyst Dwon Ruffin explains, “ Viscosity is the single most important physical property of a lubricant. CLEVELAND Ma- TestOil, the industry leader in lubricant analysis, explains viscosity, viscosity index, the considerations for selecting industrial oil with the correct viscosity and oil analysis testing that pinpoints issues resulting from viscosity.

Oil viscosity test kit