How to Determine When Oil Has Reached Its Temperature Limit

Lubricants are formulated with base oils and additives to function under the conditions expected for the intended application in terms of speed, load, temperature, oil change interval, etc. These formulas may be designed for compressors, turbines, engines, gearboxes, etc. When their properties or performance are diminished as a result of contamination, temperature changes or additive depletion, the lubricants must be modified.

Operating temperature is a significant factor in determining a lubricant’s lifespan. The higher the operating temperature, the shorter the lubricant’s service life. This is because the lubricant oxidizes, or reacts with oxygen in the air, changing its chemistry and lubricating characteristics. At higher operating temperatures, the oxidation process speeds up.

A well-known principle that pertains to lubricants is called the Arrhenius Rate Rule. It states that for every temperature increase of 18 degrees F (10 degrees C), the lubricant life is cut in half. This rule is applicable to both high- and low-quality lubricants. Even though the comparative lifespans of high- and low-quality lubricants may be different, the principle of their life being shortened with temperature is similar. Therefore, although synthetic lubricants generally have a longer life and greater resistance to temperature than mineral oils, the law of reduced life with increased temperature still applies.

While there typically is no exact maximum temperature for a lubricant to operate, very high temperatures can result in a fire hazard or require the oil to be changed too frequently.

Oxidation also produces acid compounds in the lubricant. As long as the oxidation process continues during lubricant use, the acidity of the lubricant will increase to the point where it would be recommended to change it. An acid number test can be performed to establish if the oil is still in the proper condition for operation.

Fourier transform infrared (FTIR) spectroscopy can be used to measure various compounds in the oil, including the oxidized portion. In the field, oxidation can be detected by oil darkening and its characteristic odor. However, these parameters are somewhat subjective, so it may not be easy to decide if the oil has oxidized enough to change it.

Other effects of oil degradation due to high temperatures include damage to the additives in the lubricant formula, as well as the formation of sludge, varnish and lacquers in the equipment. These factors can be identified by an internal inspection of the machinery and additional laboratory tests.




  • 25 MT daily
    production

    Our facilities have 500 mt of base-oil storage capacity and 3,000 m2 of finished products warehouse capacity. Our annual capacity is 8,000 mt of lubricants and greases.

  • 30 years of
    experience

    We have 30 years of lubricants and greases market experience. Our portfolio contains more than 200 formulations for lubricants and greases and over 600 available packaging options.

  • High Quality
    Products

    We have quality control with in-house laboratory. Our suppliers for base oils and additives are selected European companies. Half of our sales is in the neighboring export market.

KNOW MORE