What are the five indicators of lubricating oil testing?
2 Answers
Lubricating oil testing involves five key indicators: mechanical impurities, flash point, viscosity, water content, and base number/neutralization value. Mechanical impurities: Mechanical impurities refer to insoluble substances or colloidal suspensions present in lubricating oil that do not dissolve in solvents such as ethanol, gasoline, or benzene. Flash point: For oils with the same viscosity, a higher flash point is preferable. Viscosity: Viscosity measures the internal friction of a fluid in motion and indicates the oil's ability to resist flow at specific temperatures. Without additives, higher viscosity means poorer fluidity but greater oil film strength. Water content: The presence of water in lubricating oil can disrupt the oil film formation, reducing lubrication effectiveness. Base number and neutralization value: Acid number indicates the presence of acidic substances in lubricating oil, categorized into strong acid number and weak acid number.
I remember the first time I took my own lubricant for testing, the technician introduced five key indicators: viscosity testing to see if the oil is too thick or too thin, as both can affect engine protection; flash point testing to determine the temperature at which the oil ignites—too low and it can easily catch fire in summer heat; water content check to see if there’s any water mixed in, which can cause rust and corrosion; total acid number (TAN) to measure the oil’s aging—higher acidity means worse lubrication; and insolubles content to check for metal shavings or other contaminants, reflecting internal wear. Back then, my car was making a lot of noise, and the test showed excessive insolubles. After changing the oil, it immediately became much quieter. Regular testing can help detect issues early, extend the car’s lifespan, and save on repair costs.
