油箱在第一次加满后，经开机运转应该向油箱内进行二次加油，并使液压油到油位观察窗的上限，以确保油箱内有足够的油液循环。在使用过程中由于液压油氧化变质，各种理化性质下降。因此，应及时更换液压油，其换油周期可按以下几种方法确定。

1、综合分析测定法。依靠化验仪器定期取样，测定主要理化性能指标，连续监控油的变质情况。
Laboratory equipment regularly rely on sampling, measurement of key physical and chemical properties, continuous monitoring of the situation of oil deterioration.
2、固定周期换油法。是指按液压系统累计运转小时数换油，通常按使用说明书要求的周期进行更换。
By hydraulic systems operating hours accumulated oil change, usually required by manual replacement cycle.
3、经验判断法。通过采集油样与新油相比进行外观检查，观看油液有无颜色水分沉淀泡沫异味黏度等差异，综合各类情况作出外观判断和处理。
By collecting oil samples compared with new oil visual inspection, whether the color of the water to watch the oil viscosity and other differences in precipitation foam odor, appearance comprehensive judgment and making all kinds of cases handled.