注塑机温升过高会导致部件工作质量变差，油中溶解空气逸出，产生气穴，致使液压系统工作性能降低。  液压系统的理想工作温度应介乎45度－50度之间，原因是液压系统是依据一选定的压力油粘度而设计，但粘度会随着油温的高低而变化，进而影响系统中工作元件，如油缸、液压阀等，使控制精度和响应灵敏度降低，对于精密注射机的情况尤甚。同时温度过高亦会加速密封件的老化令其硬化、碎裂；温度过低则加工能量消耗大，使运转速度降低。因此密切注意液压油的工作温度是十分必要的。油温过高的原因多样，但多归于油路故障或冷却系统的失效等。
High temperature rise of injection molding machine will lead to poor working quality of parts, air dissolved in oil will escape, resulting in cavitation, which will reduce the working performance of hydraulic system. The ideal working temperature of the hydraulic system should be between 45 ℃ and 50 ℃, because the hydraulic system is designed according to the viscosity of a selected pressure oil, but the viscosity will change with the oil temperature, which will affect the working components of the system, such as oil cylinder, hydraulic valve, etc., and reduce the control precision and response sensitivity, especially for precision injection molding machines. At the same time, if the temperature is too high, it will accelerate the aging of the seal and make it harden and crack; if the temperature is too low, the processing energy consumption will be large and the running speed will be reduced. Therefore, it is necessary to pay close attention to the working temperature of hydraulic oil. The causes of high oil temperature are various, but most of them are due to the failure of oil circuit or cooling system.