What are the testing indicators for lubricating oil?
2 Answers
Lubricating oil testing indicators are as follows: 1. Viscosity: Viscosity is the most important single performance indicator of lubricating oil, forming the primary factor of the lubricating film and thus determining the load-bearing capacity of the lubricating oil. Viscosity can be divided into kinematic viscosity, dynamic viscosity, Engler viscosity, Redwood viscosity, and Saybolt viscosity. Among these, kinematic viscosity is the most commonly used representation of viscosity for lubricating oils. 2. Viscosity index: An experimental value used to indicate the degree to which the oil changes with temperature. The viscosity of a liquid decreases as temperature increases; the higher the viscosity index, the less the oil changes with temperature. 3. Density and specific gravity: The density of a liquid usually refers to the mass per unit volume at a temperature of 15°C (commonly measured in kg/m3); specific gravity, also known as relative density, refers to the ratio of the density of the liquid at 15°C to the density of an equal volume of water at the same temperature. 4. Pour point: The lowest temperature at which the cooled oil can flow. 5. Flash point: A comprehensive indicator of the fire hazard of a substance, generally it should be 20-30°C higher. 6. Demulsibility: The ability of the oil to separate from water, also known as water separation. 7. Neutralization value: The neutralization value actually includes total acid number and total base number. Generally, the neutralization value refers only to the total acid number, and its unit is also mgKOH/g.
As someone who frequently maintains my own car, there's quite a bit of know-how when it comes to lubricant testing indicators. First is viscosity, which measures how thick the oil is and directly affects engine startup and smooth operation. If it's too thick, the engine struggles to start in winter; if too thin, it provides insufficient protection in summer—requires professional instruments to measure. Next is water content—if water mixes into the oil, it turns white and emulsifies, accelerating wear, so a simple dip with test paper can reveal this. Then there's contamination level, like metal shavings and dust—testing equipment can detect fine particles, indicating severe internal engine wear. Additionally, oxidation stability matters, testing whether the oil degrades or turns acidic too quickly. If the acid value is too high, the oil corrodes parts. Before every oil change, I have professionals check these to ensure my car stays trouble-free. Regular maintenance with the right oil keeps the car running smoothly, fuel-efficient, and safe.
