Hydraulic jacks have clear instructions to clean the oil filter every two months, clean the oil tank every six months, and replace with new oil. The hydraulic circulation system of the hydraulic jack belongs to a closed structure, and the hydraulic oil does not come into contact with the outside world. So why replace the hydraulic oil with a new one?

There are two reasons for replacing hydraulic oil. Although the hydraulic oil does not come into contact with the outside world, the change in hydraulic oil performance does not necessarily involve impurities. The change in viscosity will directly affect the circulation smoothness of the hydraulic system. The change in viscosity of hydraulic oil is mainly caused by temperature, and the viscosity changes, which seriously affects the transmission efficiency. Naturally, there will be difficulties in pressing the handle and a decrease in lifting speed.

Another point is that a small amount of hydraulic oil evaporates. Although the hydraulic jack is a sealed structure, it cannot be guaranteed that a small amount of hydraulic oil will overflow under huge pressure. Over time, the hydraulic oil in the hydraulic jack will only decrease without increasing, which will directly lead to a decrease in the load-bearing capacity of the hydraulic jack. Therefore, it is necessary to add hydraulic oil in a timely manner. However, mixing new and old oil will change its viscosity, so it is more important to choose to replace the new hydraulic oil.