Identifying degraded lubricant

Several quick and simple methods to determine the quality of lubricants. 　　1. Oil flow observation method: Take two measuring cups, pour the lubricant to be tested into one of them, place the empty cup on the table, and slowly pour the lubricant from the filled cup into the empty one. Make sure to hold it 30–40 centimeters above the table at an angle, and observe its flow. If the quality of the lubricating oil is good, the oil flow will be thin, uniform, and continuous ； If the lubricant flow rate fluctuates, with large amounts of it flowing down at times, it indicates that the lubricant has deteriorated. 　　2. Manual lubricant rubbing method: Rub a drop of lubricant between the thumb and index finger repeatedly. A lubricant that provides good lubrication, produces few wear particles, and causes no friction is of high quality ； If you feel a significant friction, such as the sensation of sand between your fingers, it indicates that the lubricant contains many impurities and can no longer be used. 　　3. Oil droplet trace observation method: Take a clean white filter paper, drop a few drops of lubricant on it. Once the lubricant has seeped in, good quality lubricant does not contain any powder; it feels dry and smooth to the touch, with yellowish traces remaining. If there is black powder on the surface and a feeling of obstruction when touched by hand, it indicates that there are many impurities in the lubricant. 　　4. Sunlight exposure method: On days when there is sunlight, use a hard object to lift the lubricant at an angle of 45 degrees to the horizontal, and observe the oil droplets against the sunlight. Under lighting, if there is too much wear debris, it indicates low-quality lubricant ； It is good to see no wear debris in the lubricant.