The engine of the car is operated in various climatic conditions and at various loadings. Temperature of cooling liquid and consequently also the engine, has to be regulated and remain in the narrow temperature range that is provided with the engine cooling system.

The cooling system of tight type turns on the water pump with the drive from a belt, the radiator fan, a radiator, a broad tank, the thermostat and a radiator of a heater, hoses and switches. At launch of the cold engine cooling liquid circulates around the block of cylinders and a head of the block. Warm cooling liquid passes through a heater radiator to the water pump. As cooling liquid when heating extends, its level in a broad tank increases. Intake of cooling liquid through a radiator stops thanks to closing of the thermostat. When cooling liquid reaches a certain temperature, the thermostat opens and hot cooling liquid passes through a hose to a radiator. As cooling liquid passes through a radiator, there is its cooling with a stream of counter air.

Fig. 2.47. Components of the cooling system of the Mazda 3 cars: 1 – radiator; 2 – radiator cover; 3 – thermostat; 4 – pump of cooling liquid; 5 – cooling system fan blade; 6 – engine of the fan of the cooling system No. 1, engine of the fan of the cooling system No. 2; 7 – L3 engines; 8 – LF engines, except for engines for L8

The casing of the thermostat is located near a radiator on four-cylinder engines and in the top back part of the engine on six-cylinder engines (fig. 2.47).

Fig. 2.48. Flowchart of the cooling system of engines of the LF and L3 models: 1 – heater; 2 – radiator; 3 – broad tank of coolant; 4 – thermostat; 5 – pump of cooling liquid; 6 – head of the block of cylinders; 7 – block of cylinders; 8 – oil cooler