Thermostat: Service and Repair

REMOVAL
1. Drain coolant and tighten drain plug.
2. Remove fan shroud with cooling fan after disconnecting radiator inlet hose from radiator (H25 engine only).





3. Remove thermostat cap.
4. Remove thermostat.

INSPECTION





1. Make sure that air bleed valve of thermostat is clean. Should this valve be clogged, engine would tend to overheat.
2. Check to make sure that valve seat is free from foreign matters which would prevent valve from seating tight.
3. Check thermostat seal and O-ring for breakage, deterioration or any other damage.





4. Check thermostatic movement of wax pellet as follows:
1. Immerse thermostat in water, and heat water gradually.
2. Check that valve starts to open at specific temperature.
3. If valve starts to open at a temperature substantially below or above specific temperature, thermostat unit should be replaced with a new one. Such a unit, if reused, will bring about overcooling or overheating tendency.

INSTALLATION





1. When positioning thermostat and O-ring on thermostat case, be sure to position it so that air bleed valve comes at match mark and into the recession of thermostat case.
2. Install thermostat cap to thermostat case.
3. Install cooling fan and fan shroud and connect radiator inlet hose to radiator.
4. Fill cooling system. Refer to "COOLANT" and steps 8 to 10 of "COOLING SYSTEM FLUSH AND REFILL" located under Cooling System.
5. Connect negative cable at battery.
6. After installation, check each part for leakage.