Removal and installation, thermostat check

A thermostat with an increase in engine temperature ensures the passage of coolant to the radiator. If the thermostat fails, it does not open and the engine overheats. This is determined by the increase in the temperature gauge on the dashboard, while the radiator remains cold. A defective thermostat, however, may remain open even after the engine has cooled down. This is determined by the fact that the engine does not warm up or warms up very slowly, or the heater does not work well in winter.

Attention: If the engine becomes hot after only a short distance, the cause may be lime deposits in the radiator, fan failure or a broken V-belt.

The thermostat is located in the housing on the right rear or side of the cylinder head. A thick coolant hose leads from the housing cover to the upper radiator fitting.

Removing

Drain and collect coolant see point 3.3.

Note: It is not necessary to drain all the coolant. It is enough to lower its level below the thermostat housing.

Unscrew 2 fixing bolts -2- and lift and set aside outlet connection with connected hose -1-.

Remove gasket -3- and remove thermostat -4- from housing.

Examination

Measure the height of the thermostat, write down the size "A", see fig. SX-1802.

Slowly heat up the thermostat in a vessel of water. In this case, the thermostat should not touch the walls of the vessel. The thermostat must be completely immersed in water. Control the temperature with an appropriate thermometer.





As soon as the water reaches the set temperature, the thermostat starts opening its control valve.

Attention: The opening start temperature may vary for different valves. As a rule, it is stamped on the regulator.

Continue heating the water until the opening end temperature is reached. Pull out the thermostat, measure the height (size "b") and compare with the first value (size "A"). The opening stroke must be 8 mm, otherwise replace the thermostat.

Installation

Insert the thermostat into the housing.







Insert the thermostat into the frame of the thermostat housing. See illustrations for correct position. If the thermostat is not installed correctly, the bottom will touch the inner fin of the intake manifold or thermostat housing, so that the correct position of the mating surface cannot be achieved.


Apply a new gasket and screw on the thermostat cover with a force of 20 Nm.

Attention: If a metal gasket is installed, make sure that the symbol "UP" was turned up (to the lid).

Fill in coolant see point 3.3.

Warm up the engine in motion and check the tightness of the fitting, possibly carefully tighten the bolts.