Thermostat Check

WARNING: This page is about a different car, the 2008 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.

Immerse the thermostat in water, and heat the water while stirring. Check the thermostat valve opening temperature.
Standard value: Valve opening temperature: 76.5 ± 1.5°C (170 ± 3°F)

Fig 1: Checking Thermostat Valve Opening Temperature
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Check that the amount of valve lift is at the standard value when the water is at the full-opening temperature.
NOTE: Measure the valve height when the thermostat is fully closed, and use this measurement to compare the valve height when the thermostat is fully open.

Standard value:

Full-opening temperature: 90°C (194°F)

Amount of valve lift: 8.5 mm (0.33 inch) or more

Fig 2: Identifying Valve Height
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.