Engine lubricating oil (also called lubricating oil) has the functions of cooling, cleaning, sealing, rust prevention and vibration absorption. The quality of engine oil plays an important role in the normal operation of the engine. However, with the increase of use time and the emergence of machine failure, the lubricating oil will lose the lubrication performance because of the water, fuel and metal particles, which leads to the deterioration of the oil. Deterioration of lubricating oil will result in a decrease in lubrication performance, which will aggravate the wear and tear of the engine parts, thereby affecting the power, economy and emission of the engine. After the oil deterioration, the cold car will not start easily. In winter, the lubricating oil increases, the fluidity is poor, the glue is easy to be bonded and the acidification is aggravated, thus increasing the wear of the engine cylinder. After the oil is deteriorated, the cleaning function will be reduced, and the deteriorated oil not only does not lubricate the surface of the parts, but also accelerates the wear of the surface of the machine. After deterioration of oil, the sealing performance will be reduced, which will directly affect the power performance of the engine. Therefore, we should check in time and find out the problems in time, so as not to affect the use and lead to greater losses.