Thermostat Test

Replace the thermostat if it is stuck in the open position at room temperature.

To test a closed thermostat:

1. Suspend the thermostat (A) in a container of water. Do not let the thermostat and the thermometer (B) touch the bottom of the hot container.
   Fig 1: Checking Thermostat Opening Temperature

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
2. Heat the water, and check the temperature with a thermometer. Check the temperature at which the thermostat first opens, and at which it is fully open.
3. Measure the lift height of the thermostat when it is fully open.

   Standard Thermostat 

   Lift Height: Above 8.0 mm (0.315 in) 

   Starts Opening: 169-176°F (76-80°C) 

   Fully Open: 194°F (90°C)