Removal and installation, checking of the thermostat (Mitsubishi Lancer 3)

A thermostat with an increase in engine temperature ensures the passage of coolant into 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, can remain open 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.

Caution: If the engine becomes hot after only a short distance, the cause may be limescale deposits in the radiator, a 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 runs from the housing cover to the upper radiator nipple.

Removal

Drain and collect the coolant, see p. 3.3.

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

Unscrew the 2 mounting bolts "2" and lift and set aside the outlet fitting with the connected hose "1".



Remove gasket "3" and take thermostat "4" out of the housing.

Examination

Measure the height of the thermostat, write down the dimension "a", see Fig. SX - 1802.

Slowly heat the thermostat in a vessel with water. The thermostat should not touch the walls of the vessel. The thermostat should be completely immersed in water. Monitor the temperature with an appropriate thermometer.





As soon as the water reaches the set temperature, the thermostat begins to open its control valve.

Note: The opening temperature may vary for different valves. It is usually stamped on the regulator.

Continue heating the water until the end opening temperature is reached. Remove the thermostat, measure the height (dimension "b") and compare with the first value (dimension "a"). The opening stroke should be 8 mm, otherwise replace the thermostat.

Installation

Insert the thermostat into the housing.







Insert the thermostat into the thermostat housing frame. Refer to the illustrations for the correct position. If the thermostat is not installed correctly, the bottom will touch the inner rib of the intake manifold or the thermostat housing, preventing the correct mating surface from being achieved.



Apply a new gasket and tighten the thermostat cover with a torque of 20 Nm.

Caution: If a metal gasket is installed, ensure that the "UP" marking faces upwards (towards the cover).

Fill with coolant, see p. 3.3.

Warm up the engine while driving and check the tightness of the fitting, perhaps carefully tighten the bolts.