Such as whether the bolt is tightened, the piston ring is installed correctly, damaged oil seal is replaced, etc.
譬如螺栓是否拧紧，活塞环安装是否正确，损坏油封是否更换等。
2
Loosen oil pan bolts and remove the front bolt at each side.
松动油底壳螺栓，拆下每一面的前螺栓。
3
According to actual case of thermal recovery in oil field, strengths were checked on pretighten force and working state, and the rigidity was test for failure bolt.