The oil temperature of four column oil pressure shall be appropriate. The oil temperature of the oil tank shall not exceed 60 ℃. It is more appropriate to control it within the range of 35 ~ 55 ℃. From the point of view of maintenance, too high oil temperature should also be absolutely avoided. If the oil temperature rises abnormally, it shall be checked.  
 
Common reasons are as follows:  
1. The viscosity of oil is too high;  
2. The oil quality deteriorates and the resistance increases;  
3. The performance of the cooler is poor, such as insufficient water, scale in the pipeline, etc. 4. The air in the circuit shall be completely removed. After air enters the circuit, because the volume of the gas is inversely proportional to the pressure, the movement of the hydraulic cylinder will be affected with the change of load, so air mixing should be avoided in particular). In addition, air is an important cause of oil deterioration and heating;  
 
Pay special attention to the following items when the oil temperature of the four column oil press rises:  
① After the inlet filter is blocked, the suction resistance increases greatly, and the air dissolved in the oil is separated, resulting in the so-called cavitation phenomenon;  
② Pay attention not to leak air at places below atmospheric pressure such as suction pipe and pump shaft sealing part;  
 
When the four column hydraulic press starts the hydraulic pump for the first time or does not run for a long time, pay attention to the following matters:  
① Fill the pump with working medium;  
② Check whether the rotation direction is correct;  
When starting the hydraulic pump of four column oil press at low temperature, pay attention to the following matters:  
When starting the hydraulic pump in cold areas or winter, it should start and stop, reciprocating several times to increase the oil temperature, and enter the formal operation after the hydraulic device operates flexibly.