Section 14 (Cooling): Thermostat: Inspection

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

INSPECT WATER INLET SUB-ASSEMBLY WITH THERMOSTAT
HINT

The water inlet sub-assembly with thermostat is stamped with the valve opening temperature.

Fig 1: Identifying Water Inlet Sub-Assembly With Thermostat
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Immerse the water inlet sub-assembly with thermostat in water and gradually heat the water.
2. Check the valve opening temperature
  Standard valve opening temperature:
  
  80 to 84°C (176 to 183°F)
  
  If the valve opening temperature is not within the specified range, replace the water inlet sub-assembly with thermostat
  
  Fig 2: Checking Valve Opening Temperature
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check the valve lift
  Standard valve lift:
  
  10.0 mm (0.394 in.) or more at 95°C (203°F)
  
  If the valve lift is not as specified, replace the water inlet sub-assembly with thermostat
  
  Fig 3: Checking Valve Lift
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check that the valve closes when the water inlet sub-assembly with thermostat is at a low temperature (below 77°C (171°F))
  If it does not close as specified, replace the water inlet sub-assembly with thermostat.