During the working process of the engine, the performance of lubricating oil is constantly declining. If it is not replaced in time, it will cause damage to the engine. Therefore, we should master some simple methods to identify the deterioration of lubricating oil.
Oil Flow Observation Method
Take two measuring cups, one containing the lubricating oil to be checked, and the other empty on the table. Lift the measuring cup full of lubricating oil 30-40 cm away from the table top and tilt it, let the lubricating oil slowly flow into the empty cup, and observe its flow. If the oil flow is suddenly fast and slow, and sometimes large pieces flow down, it means that the lubricating oil has deteriorated.
Hand twisting method
Twist the lubricating oil between the thumb and index finger for repeated grinding. There are few chips and no friction. If you feel a large friction such as sand between your fingers, it indicates that there are too many impurities in the lubricating oil and can no longer be used. You should replace the new lubricating oil.
Lighting method
On a sunny day, use a screwdriver to lift the lubricating oil at a 45-degree angle to the horizontal. Observe the oil droplets against the sunlight. In the light, you can clearly see that there is no wear debris in the lubricating oil, which is good and can continue to function. If the wear debris is too much, the lubricating oil should be replaced.
Oil drop trace method
Take a clean white filter test paper, drop a few drops of oil on the filter test paper, and after the lubricating oil leaks, If there is black powder on the surface and there is a sense of astringency when you touch it with your hands, it means that there are many impurities in the lubricating oil. A good lubricating oil has no powder, and it is dry and smooth to the touch with yellow marks.