The common misunderstandings in the use of air compressor lubricating oil are mainly the following:

       1. The more air compressor oil you add, the better. The main function of air compressor oil is to lubricate the machine, reduce friction and wear. When the oil is insufficient, it will accelerate the deterioration of the lubricating oil, and even cause adhesion and abnormal wear of parts due to lack of oil. However, too much lubricating oil is not advisable for two reasons: first, too much lubricating oil will enter the combustion chamber from the gap between the cylinder and the piston to cause carbon deposits; second, it increases the mixing resistance of the crankshaft connecting rod, which increases fuel consumption. Tests show that when the refueling amount exceeds the standard by 1%, the fuel consumption will increase by 1.2%. Therefore, refueling must follow the principle of “small amount, frequent refueling” to keep the oil level between 2/4-4/4.

       2. The higher the viscosity of the air compressor oil, the better. Many people think that the higher the viscosity of the air compressor oil, the better. The higher the grade of the air compressor oil (the number of centistokes of kinematic viscosity at 100°C), the better. In fact, this understanding is one-sided. The higher the viscosity, the thicker the oil film between the friction surfaces of the moving parts. Although the thick oil film is conducive to preventing the wear of the friction surface, the friction resistance is also large, and the power loss increases. Foreign data show that a decrease of 1 centistokes in the viscosity of the air compressor oil can save about 1.5% of fuel. In addition, experiments have also shown that when the viscosity of the air compressor oil exceeds the requirements, it will also increase the wear of the parts, because about 2/3 of the wear of the parts occurs at the beginning of the start. Using a lubricating oil with high viscosity and starting at low temperature, because after a period of shutdown, the smooth oil on the friction surface has been lost, and the viscosity is high and the flow is slow, it cannot be replenished to the friction surface in time to form a smooth oil film, so the parts will be in a dry friction and semi-dry friction state for a long time, which will lead to increased wear of the parts. Therefore, the viscosity of the air compressor lubricant is not the higher the better, but the lower the viscosity of the lubricant should be, the lower the viscosity of the lubricant should be.

       3. When should the air compressor oil be replaced when it is used up? Some people think that the lubricating oil does not need to be replaced as long as it is not used up. If the amount is small, just add some new oil. This practice is unscientific, because the quality of lubricating oil is a key factor affecting the reliability and service life of the air compressor. Timely replacement of lubricating oil is the guarantee of reliable lubrication of the air compressor. During the use of lubricating oil, due to pollution, oxidation and other reasons, the quality will gradually decline, and there will also be some consumption, which will reduce the amount. Continuously adding some new oil to the lubrication system can only make up for the lack of quantity, but cannot completely compensate for the loss of lubricating oil function. With the extension of time, the function of lubricating oil will become worse and worse, which will have a serious impact on the air compressor, such as a sharp increase in sediments in the air compressor, a decrease in power function, and early wear of parts, which will eventually lead to functional failures. In order to ensure the normal operation of the air compressor for a long time and reduce wear, the lubricating oil must be replaced in time according to regulations.