Caution: Be careful when handling antifreeze. Do not allow antifreeze to come into contact with the skin: it is toxic.
Do not start work until the engine has completely cooled down.
Control
1. Before you tackle the thermostat as a source of engine problems, check the coolant level (see chapter 1) and operation of the temperature sensor (or indicator light).
2. If the engine has a long warm-up time, it is likely that the thermostat is fully open. Replace thermostat.
3. If the engine overheats, check the temperature of the upper radiator tank, for example, with your hands. If the engine is hot and the tank is cold, the thermostat is closed. Replace thermostat.
Attention: do not operate the engine without a thermostat. This will lead to errors in the control of engine systems by a computer and, as a result, an increase in fuel consumption and the emission of toxic components.
4. In difficult cases of diagnosing the operation of the cooling system, see Section "Malfunction" at the beginning of this guide.
Replacement
5. Disconnect the negative cable from the battery.
6. Drain the cooling system (see chapter 1). If the coolant is in relatively good condition, it can be reused (see chapter 1).
7. The lower radiator hose will lead you to the thermostat housing.
8. Cut through the wire tie and remove the hose from the thermostat housing. If the hose is damaged, replace it.
9. If the outer surface of the body nozzle is damaged by corrosion or other reasons, replace the body cap with this nozzle.
10. Turn away bolts of fastening and remove a cover of the thermostat (see fig. 3.10). If the cover is stuck, knock it down with hammer blows. Be prepared for some of the coolant to spill.
Pic. 3.10 Thermostat and fittings: 1 - body; 2 - temperature sensor; 3 - housing cover; 4 - gasket; 5 - thermostat; 6 - rubber ring; 7 - water pump inlet pipe.
11. Remember position of installation of the thermostat and remove it.
12. Close the inlet holes in the engine with a rag, clean the connecting surfaces from the remnants of the gasket and seal. Wipe the surfaces with thinner or benzine.
13. Install a new thermostat. The correct position of the thermostat is that the side with the spring is facing the engine, the vent is pointing up.
14. Lubricate both sides of the gasket with a thin layer of sealant and install on the housing.
15. Install cover, tighten bolts to specification.
16. Connect the lower radiator hose. Install the band clamp and tighten it.
17. Fill the cooling system (see chapter 1).
18. Start engine, check for leaks and thermostat operation (steps 2, 3, 4 of this section).