There are generally only these reasons for cat skid steer coolant tank leakage: the cooling system leaks, or pure water is used in the water tank, the coolant is not used as required or the coolant contains too much water.
The coolant level in the coolant tank should remain basically the same under normal conditions. After the car has been driven for a few years, it should include checking for leaks. The way to check is actually quite simple. First, check whether there is any trace of antifreeze on the parking space floor and the corresponding position of the water tank. Next, look up from the lower part of the front of the car. If there are water marks on the lower part of the tank or the pipes, it is leaking and needs to be repaired.
The loud fan noise is also related to the temperature of the water tank. When the temperature of the water tank exceeds a certain temperature, the fan will start to work. If the temperature of the water tank is not high, the fan does not have to work and the sound is low.
If you can safely rule out water leakage, then the antifreeze used in the 4S store is too diluted and the content is insufficient. The antifreeze concentration should be increased. The best ratio is half antifreeze and half water, so that you can go for a long time (a year or two or even longer) without adding antifreeze.
Pure water will boil at 100 degrees Celsius, and the vaporized water will run out of the tank under high pressure, so the amount of water will gradually decrease. A similar problem occurs when the antifreeze concentration is insufficient. As long as the coolant boils during normal operation of the car, it will be reduced by volatilization. High-quality coolant will not boil during normal operation, so it will not volatilize or reduce for a long time.