Section 167 (Engine Cooling System (2AZ-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 Opening Temperature Of Thermostat
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)
  
  Fig 3: Checking Thermostat Valve Lift
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If the valve lift is not as specified, replace the thermostat.
4. Check that the valve is fully closed when the thermostat is at low temperatures (below 77°C (171°F).
  If it is not fully closed, replace the thermostat.