Drain the old liquid, connect the tap water pipe to the replenishment tank, let clean water flow through the engine cooling system continuously, and then start idling for 3-5 minutes to circulate the water until the clean water flows out. (Be careful not to forget to remove the heating water pipe and clean the water in the heating water tank. )
After draining about 1 hour, add new antifreeze from the water pipe of the water tank (radiator) to make the antifreeze flow into the water tank quickly. Then add another bucket of antifreeze to the antifreeze tank until the antifreeze tank is almost full. Start the engine, run it for 10 minutes, and let the antifreeze circulate and exhaust. After that, the liquid level will drop and antifreeze will be added. Repeat this process until the liquid level is between the minimum and maximum level marks.