Toyota RAV4>> Cooling and air-conditioning systems>> The general data>> Cooling system
The car engine is maintained in various environmental conditions and at various loadings. Thus the temperature of a cooling liquid should remain in a narrow temperature range that the system of cooling of the engine provides.
The cooling system closed liquid, includes the water pump with a drive an auxiliary belt from a cranked shaft, the fan of a radiator with an electric drive, a radiator, a broad tank, the thermostat, a heater radiator, hoses and switches.
The water pump лопастного type is established in front on the block of cylinders.
The thermostat depending on temperature of a cooling liquid automatically includes or disconnects a radiator of system of cooling, passing a liquid through a radiator or passing it.
At start-up of the cold engine the cooling liquid does not arrive in a radiator as the basic valve of the thermostat is closed, and перепускной is opened. The cooling liquid circulates on a shirt of the block and a head of the block of cylinders, then again arrives in the pump. So fast warming up of the cold engine is provided.
When the cooling liquid will reach temperatures of opening of the thermostat, firm wax наполнитель the thermostat extends, compresses a rubber insert and pushes out the piston. Thus the basic valve will open completely, and перепускной will completely be closed. The hot cooling liquid passes through a hose to a radiator and is cooled by a stream of counter air.
The radiator fan joins a thermoswitch depending on temperature of a cooling liquid.
The cooling radiator is closed by a tight cover. The cover creates an elevated pressure in cooling system that lifts temperature of boiling of a cooling liquid, and more the heat of boiling of a cooling liquid increases efficiency of a radiator. If pressure in system exceeds a preset value, the safety valve in a cover opens and lets out cooling liquid through a hose in a broad tank. At cooling the cooling liquid flows from a tank back in a radiator.
The broad tank carries out two functions: serves as capacity for gathering нагретой to a cooling liquid and for replenishment of system of cooling.
Air submitted system of ventilation in salon of the car, can be warmed up or be cooled, depending on the conditions of comfort chosen by the driver and passengers. Heating and air-conditioning systems separate, however their units and knots settle down in car salon in the general case under the panel of devices. All stream of air submitted to salon goes for heating or cooling through the same air lines. The temperature and speed of a stream of air is regulated by means of the same controls.
Heat allocated at work of the engine, is transferred by a cooling liquid to the radiator of a heater located in salon. The stream of air from the salon fan passes through a radiator and heats up heat of a cooling liquid.
If air leaving ventilating lattices, does not heat up, following reasons are possible:
– The thermostat is constantly opened, therefore the cooling liquid does not heat up to the demanded temperature and does not transfer enough of heat to a heater radiator. In this case replace the thermostat;
– Hoses of giving of a cooling liquid to a heater radiator are littered. Check up temperature of hoses about a partition of a motor compartment, they should be hot. If one of hoses cold, means, there is a contamination of hoses or a heater radiator. Disconnect hoses from unions on a partition of a motor compartment and, by turns submitting water under pressure to unions, wash out hoses and a heater radiator;
– If washing of a radiator of a heater has not given positive results, replace a radiator.
Cooling liquid

       THE PREVENTION
Do not suppose hit of a cooling liquid on clothes and a paint and varnish covering of a body. Otherwise wash out a surface a water considerable quantity.
Collect and utilise the merged cooling liquid.

The cooling system should be all year long filled by a cooling liquid. The cooling liquid represents a mix этиленгликолевого antifreeze and the distilled water in the ratio 50:50. In zones with a frigid climate the antifreeze maintenance in a cooling liquid can be increased according to recommendations of the manufacturer of a liquid, however should not exceed 70 %.
Optimum concentration of antifreeze excludes liquid freezing in the block of cylinders of the engine, formation of corrosion and a limy deposit, and also increases temperature of boiling of a cooling liquid.
Replacement of a cooling liquid with washing of system of cooling is necessary for making alternate years. Before filling of system of cooling check up a condition of hoses and their fastenings. While in service the car level of a cooling liquid should not change. Fast falling of level of a cooling liquid specifies in a leak and necessity of its elimination. Check up a condition of a radiator, the water pump, hoses, connections and stoppers plum on presence on them of traces подтекания. If leaks are not found out, check up at servicing deport pressure of opening of the valve in a radiator cover.
Replacement of a cooling liquid is necessary for making also after carrying out of any works on elements of system of cooling with сливом a cooling liquid. If at repair the head of the block of cylinders, a lining of a head of the block, a radiator or the oil heat exchanger were replaced, fill in in cooling system a fresh cooling liquid. It is connected by that the anticorrosive additive in a cooling liquid at engine work is besieged and creates anticorrosive protection. In the cooling liquid which were in operation, anticorrosive additives are insufficiently active to form a protective layer on again established details.