Note: Use a new O-ring.
Examination
Replace the thermostat if it is open at room temperature.
To check a closed thermostat:
1. Place the thermostat over a container of water as shown.
2. Heat the water and measure the temperature with a thermometer. Note the temperature at which the thermostat begins to open and the temperature at which the thermostat is fully opened.
Caution: Do not allow the thermometer to touch the bottom of the container.
3. Measure the thermostat opening value when fully open.
Standard thermostat:
Opening size: above 8.0 mm
- opening start: 76-80°C
- full opening: 90°C
Engine D15Z1:
- opening start: 80-84°C
- full opening: 95°C
