Pic. 468. Coolant pump: 1 - bolt, 20 Nm; 2 - coolant pump; 3 - bolt, 10 Nm; 4 - bolt, 10 Nm; 5 - coolant temperature sensor, 7 Nm; 6 - thermostat; 7 - bolt, 10 Nm; A - attached to the cylinder head; B - to the heat exchanger; C - to the heater core; D - from the radiator
The thermostat controls the redistribution of coolant flows in the engine cooling system. The thermostat is located in the water pump housing under the cover, which has an O-ring (pic. 468).
How to remove the thermostat (work is carried out on a cold engine):
- drain the coolant from the cooling system;
- disconnect the supply hose;
- remove the thermostat cover;
- remove the thermostat with the o-ring.
Note. For easy access to the thermostat, raise the front of the car and place it on stands.
The thermostat cannot be repaired, so if it malfunctions, replace it. A simple thermostat test is carried out as follows:
Pic. 192. Checking the functionality of the thermostat
- hang the thermostat on a wire and lower it into a vessel of cold water (pic. 192);
- hang thermometer (with a temperature measurement interval of at least 10–120°C) so that it does not touch the bottom of the vessel;
- heat the water.
Check:
- 1) whether the thermostat will open at 85°C;
- 2) at 105°C the thermostat must open fully;
- 3) The thermostat pin must protrude from the housing by at least 7 mm.
If the thermostat fails this test, it must be replaced.
Use a new gasket when installing the thermostat. Check the hose clamp before reinstalling it on the hose. Pour coolant into the cooling system as described in paragraph 19.1.1.
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