Thermostat: Service and Repair

REMOVAL

WARNING: Never remove the radiator cap when the engine is hot. Serious burns could occur from high pressure coolant escaping from the radiator.

CAUTION: Perform when the engine cold.

Thermostat
1. Drain engine coolant.
2. Remove the lower radiator hose from the water inlet housing.
3. Remove the water inlet housing.
4. Remove the thermostat.

Water Control Valve
1. Drain engine coolant.
2. Remove the upper radiator hose, heater pipe, and heater hose.
3. Remove the water outlet housing.
4. Remove the water control valve.

INSPECTION AFTER REMOVAL





^ Place a string so that it is caught in the valve of the thermostat (or water control valve) and suspend it in boiling water. It must be fully immersed in the water.
^ The valve opening temperature is the temperature at which the valve plate begins to rise from the top plate causing the thermostat to fall off of the string.
^ Continue heating the water and thermostat to check the full-open valve lift distance.

NOTE: The full-open lift amount standard temperature for the thermostat (water control valve) is the reference value.

^ After checking the full-open lift amount, lower the water temperature and check the valve closing temperature.





Standard Values

INSTALLATION
^ Installation is in the reverse order of removal.

Thermostat and Water Control Valve





^ Install the thermostat and water control valve with the whole circumference of each flange fitting securely inside the rubber ring. (The example in the figure shown is the thermostat.)





^ Install the thermostat with the jiggle-valve facing upwards. (The position deviation may be within the range of ±10°)
^ Install the water control valve with the up-mark facing up and the frame center part facing upwards. The position deviation may be within the range of ±10° of vertical.

Heater Pipe
^ Apply clean coolant to the heater pipe O-ring, and immediately install the heater pipe into the installation holes.