Cooling System: Inspection

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT THERMOSTAT
HINT:

The thermostat is inscribed with the valve opening temperature.

Fig 1: Identifying Temperature Valve
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Immerse the thermostat in water, then gradually heat the water.
  
  Fig 2: Immersing Thermostat In Water
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Inspect the valve opening temperature of the thermostat.
  Valve opening temperature: 80 to 84°C (176 to 183°F)
  
  If the valve opening temperature is not as specified, replace the thermostat.
3. Inspect the valve lift.
  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: Inspecting Valve Lift
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Check that the valve is fully closed when the thermostat is at low temperature (below 77°C (171°F)).
  If not fully closed, replace the thermostat.
INSPECT WATER OUTLET CAP SUB-ASSY
NOTE:
- If the water outlet cap is contaminated, rinse it with water.
- Before using a radiator cap tester, wet the relief valve and pressure valve with engine coolant or water.
- When performing the following steps ( a) and ( b), keep the tester at an angle of over 30° above horizontal.
1. Using a radiator cap tester, slowly pump the tester and check that air is coming from the vacuum valve.
  Pump speed: 1 push / 3 seconds or more
  
  Fig 4: Slowly Pumping Tester & Checking Air Coming From Vacuum Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: Push the pump at a constant speed.
  
  If air is not coming from the vacuum valve, replace the water outlet cap.
2. Pump the tester, then measure the relief valve opening pressure.
  Pump speed: 1 push within 1 second
  
  NOTE: The above pump speed is for the first pump only (in order to close the vacuum valve). After the first pump, the pump speed can be reduced.
  
  Standard opening pressure: 83 to 113 kPa (0.85 to 1.15 kgf/cm ² , 12.1 to 16.4 psi)
  
  Minimum opening pressure: 69 kPa (0.7 kgf/cm ² , 10.0 psi)
  
  HINT:
  
  Use the tester's maximum reading as the opening pressure. If the opening pressure is less than minimum, replace the water outlet cap.