Hahaha, there is no dog problem, we are to answer their concerns, and I always say the same there are no silly questions if not dumb that they do not ask, the level in the cooling deposit indicates the maximum level of water allowed by the system, indicates that the water system is completely full, the rest of the deposit that remains empty is to support the increase in the volume devided to the water temperature, it is filled to the maximum level to ensure that no bubble Air is in the system, since if this could happen, it could happen that this bubble is lodged in the bulb or temperature sensor, its proper functioning prevented.