Thermostat: Service and Repair

THERMOSTAT REMOVAL
1. Disconnect negative cable at battery.
2. Drain cooling system and tighten drain plug.
3. Remove outlet pipe bracket bolt.





4. Disconnect thermostat cap from thermostat case.





5. 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 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 on thermostat case, be sure to position it so that air bleed valve comes uppermost and into the recession of thermostat case.
2. Install thermostat cap to thermostat case. When installing cap, align arrow marks on cap and case.
3. Install outlet pipe bracket bolt.
4. Fill cooling system.
5. Connect negative cable.
6. After installation, check each part for leakage.