The automobile gantry is actually the water tank frame, which is located in the front of the automobile. There are three kinds of water tank frames on the market: plastic, iron or alloy. According to the structure, it can be divided into integral type and split type. Split type is the most common form in the market, while split type is generally divided into three sections, which are connected by bolts or solder joints. The following is the method to check whether the water tank frame has been replaced: 1. Check the frame solder joints: Are there any traces of re-grinding the frame solder joints? 2. Check the trace of the frame: Is there any trace of plastic? 3. Check the paint marks of the frame: Is the paint of the frame consistent with the paint of the engine compartment? Did you touch up the paint? Or did you redraw a complete trace? 4. Check the side of the car body: Are there any signs of collision repair? 5. Check whether the door is defective: whether it is close to the body, whether it is warped, and whether the door crack is uniform. If it is repaired or replaced, there will definitely be some defects.