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5.3.10. Thermostat

The thermostat operates the direction of a stream of cooling liquid. The element reacting to change of temperature with a spring in process of heating of the engine operates two gates which depending on temperature condition direct a stream of cooling liquid in whole or in part on the corresponding contour.
1. Circulation on a small contour (temperature to +87 °C) – the thermostat is closed. Perepuskna the valve directs cooling liquid to the pump. From there liquid moves in the engine again. This mode serves for bystry warming up of the engine.
2. The mixed mode (temperature +87... +102 °C) – the thermostat open. Liquid, circulating on a small contour, partially passes through a radiator.
3. Circulation on a big contour (temperature more than +102 °C) – the thermostat is completely open. All liquid passes through a radiator.
   Removal and check of the thermostat
If the thermostat clogs, it can lead to big damages to the engine. Liquid will begin to boil and will quickly evaporate. In this case it is impossible to continue the movement. Tow off the car to the place of repair. Removal and installation of the thermostat — work simple. Buying the new thermostat, do not forget new laying including laying of the case. You also need capacity for liquid discharge. Remove the thermostat only on the cold engine. At different models of the case of thermostats differ on an arrangement a little.

1. Disconnect a wire from the negative plug of the rechargeable battery.
2. Merge cooling liquid as it is described earlier.
3. Remove a forward top casing of the engine.
4. Weaken a collar, disconnect a radiator hose from the thermostat case.
5. Disconnect a small hose of a broad tank (previously having weakened a collar).

Fig. 4.47. Thermostat arrangement: 1 – thermostat case; 2 – pump of cooling liquid; 3 – natyazhitel of a chain; 4 – final collector

Fig. 4.48. The pump of cooling liquid in the block with the thermostat: 1 – flange of a pulley of a maple belt; 2 – pump housing; 3 – krylchatka of the pump; 4 – radiator hose union; 5 – thermostat case; 6 – thermostat; And — from a radiator; In — from the engine; With — to the engine

6. Unscrew the case of the thermostat and take out together with it (fig. 4.47). The thermostat is grouped with the water pump (fig. 4.48).

Fig. 4.49. Check of the thermostat

7. Place the thermostat in the container with water (fig. 4.49) and way of slow heating of water check operation temperature. For the thermostat which was already in operation the difference in operation temperature in limits ± 3 °C is admissible.
8. Check that when cooling the valve was completely closed.
9. At misoperation replace the thermostat. On 4-and 6-cylinder engines the thermostat has a one-piece design.
10. Before installation of the thermostat clear junctions with laying on the case and the engine.
11. Install the case with the thermostat and new laying and wrap the moment of 10 N · m.
12. Connect a radiator hose, pay attention to its correct landing and a reliable inhaling of a collar.
13. Fill in cooling liquid.
14. Connect a wire to the negative plug of the rechargeable battery.
15. Warm up the engine and be convinced that below the radiator heats up.
16. Check tightness of installation of the thermostat.