Section 175 (Engine Cooling System (2GR-FE)): Thermostat: Inspection

WARNING: This page is about a different car, the 2008 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT THERMOSTAT
HINT:

The valve opening temperature is inscribed on the thermostat.

Fig 1: Identifying Thermostat Opening Temperature
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Immerse the thermostat in water, and then gradually heat the water.
2. Check the valve opening temperature of the thermostat.
  Standard valve opening temperature: 80 to 84°C (176 to 183°F)
  
  If the valve opening temperature is not as specified, replace the thermostat.
  
  Fig 2: Checking Valve Opening Temperature Of Thermostat
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check the valve lift.
  Standard valve lift: 10 mm (0.39 in.) or more at 95°C (203°F)
  
  If the valve lift is not as specified, replace the thermostat.
  
  Fig 3: Checking Valve Lift
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check that the valve is fully closed when the thermostat is at low temperatures (below 77°C (171°F)).
  If not fully closed, replace the thermostat.