What signals indicate that it’s time to change the lubricating oil?

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It is very important to understand the condition of your lubricant in order to ensure the proper operation of your machinery. This can be achieved through thorough oil analysis, which allows for the tracking of a range of oil characteristics related to wear by comparing them with previous analysis reports. This level of analysis can identify issues such as contamination, degradation of lubricating oil, and general mechanical wear. It can also change the lubrication schedule from time-based to condition-based, reducing unnecessary replacements. Today, let’s talk about the signs that indicate it’s time to change the oil. 1. Total alkalinity: Measures the oxide content in the lubricant from the start of operation up to this point. It can detect the condition of the lubricant, or identify signs that it is time to replace it. As lubricant is used, it is exposed to air, causing the level of oxides to increase continuously and the efficiency of the lubricant to decline gradually. If the total acid value exceeds its initial value by a large margin, it is a warning sign of problems with the lubricant. Equally important is the particle count in the lubrication system. This indicator tells people the cleanliness of the lubricating oil and the performance of the filtration system. Impurities and other stains continue to accumulate, reducing the efficiency of the oil. A high-performance filtration system can extend the time available for testing. However, if the particle count is far above its initial value, this is also a good sign that it’s time to change the lubricant. 2. Water: Water is the natural enemy of lubricants. Especially in humid environments, where the lubricant is exposed directly to water or water vapor, the performance of the lubricant containing water is significantly reduced. Different lubricants have different tolerances for water content. For example, polyglycols are more sensitive to water than polyα-olefin products. Each type of lubricant has recommended guidelines for acceptable moisture content, which can be obtained from the lubricant supplier. No matter what lubricant you use, an excessive water content is a serious warning sign: change the oil immediately! 3. Metals: Metal analysis can reveal wear data in the lubrication system as well as the performance of certain additives. The metals in lubricating oil are the result of both additives in the fluid and wear, depending on the type of lubricant and the system design. Typical oil samples are bonded to metals in ordinary engines, such as copper, aluminum, and iron, which allows for the detection of the amount of metal that has been \"absorbed\" by the lubricant. Just like moisture content, different lubricants also have varying tolerances for metal content. Furthermore, plant managers should consult their lubricant suppliers for the best solution after conducting metal testing and determining that oil change is necessary. 4. Particle analysis: Particle analysis can help detect metal contamination and ensure that the lubrication system has proper filters, thereby **extending** the time between oil changes. 5. Viscosity: Perhaps the simplest parameter in lubricant wear tests is the dynamic viscosity of the lubricant, which can also be considered as its concentration. By tracking the lubricating oil in quantitative operations, it is easy to detect that its viscosity is increasing. An increase in viscosity is directly related to lubrication wear. Remember the most important rule: once the viscosity of the lubricating oil increases by 10%, replace it immediately.