Thermostat Test

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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

To test a closed thermostat:

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: Testing Thermostat
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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.
Measure the lift height of the thermostat when it is fully open.
Standard Thermostat

Lift Height: Above 10.0 mm (0.394 in)

Starts Opening: 169-176°F (76-80°C)

Fully Open: 194°F (90°C)