The air mixed in hydraulic oil will escape from the oil and form bubbles in the low pressure region. When the bubble moves to the high pressure region, it will be crushed by high pressure, and when the bubble is broken, it will receive a large amount of heat and cause the oil temperature to rise. Accompanied by hydraulic noise.
If the above phenomenon occurs, check whether the hydraulic pump inlet joint is tightened, whether the seal is reliable, and if there is any problem, fasten the seal. At the same time pay attention to each oil change to exhaust the air in the system.