Temperatures of over 2.000C° during a full-load operation require efficient cooling which is made possible through the cooling circuit. The mix of water and coolant flows through a complex system consisting of a small and large circuit. During the engine’s warm-up, the fluid circulates through the cylinder and the head of the cylinder (small cooling circuit). As soon as the needed operating temperature is reached, the access to the cooler is opened. Consequently, the coolant’s temperature is reduced by outside air (large cooling circuit). The main purpose of a cooling circuit is to allow the engine to quickly reach the desired temperature, ensuring a constant operating temperature and preventing overheating. In addition, the cooling circuit makes it possible for the interior of the vehicle to warm-up.