Engine Cooling System: Thermostat: Inspection

INSPECT THERMOSTAT
1. Inspect the thermostat.
  HINT:
  
  The valve opening temperature is inscribed on the thermostat.
  
  Fig 1: Identifying Temperature Mark On Thermostat
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Immerse the thermostat in water and gradually heat the water.
3. Check the valve opening temperature.
  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
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check the valve lift.
  Valve lift:
  
  7.7 mm (0.3031 in.) or more at 95°C (203°F)
  
  If the valve lift is not as specified, replace the thermostat.
5. Check that the valve is fully closed when the thermostat is at low temperatures (below 40°C (104°F)).
  If it is not fully closed, replace the thermostat.
  
  Fig 3: Checking Valve Lift
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002