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Cooling System: Inspection

  1. Thermostat.
    NOTE: The thermostat is numbered with the valve opening temperature.
    Fig 1: Displaying Valve Opening Temperature
    G01207016Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Immerse the thermostat in water and gradually heat the water.
    2. Check the valve opening temperature.

      Valve opening temperature  : 80-84°C(176-183°F)

      If the valve opening temperature is not as specified, replace the thermostat.

      Fig 2: Checking Valve Opening Temperature
      G01207017Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the valve lift.

      Valve lift  : 10 mm (0.394 in.) or more at 95°C (203°F)

      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 not closed, replace the thermostat.

    Fig 3: Checking Valve Lift
    G01207018Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Water outlet cap sub-assembly.
    NOTE:
    • If the reservoir cap has contaminations, always rinse it with water.
    • Before using a radiator cap tester, wet the relief valve and pressure valve with engine coolant or water.
    • When performing steps (a) and (b) below, keep the tester at an angle of over 30° above the horizontal.
    1. Using a radiator cap tester, slowly pump the tester and check that air is coming from the vacuum valve.

      Pump speed  : One push/3 seconds or more

      NOTE: Push the pump at a constant speed.

      If air is not coming from the vacuum valve, replace the reservoir cap.

    2. Pump the tester and measure the relief valve opening pressure.

      Pump speed  : One push within one second

      Fig 4: Displaying Radiator Cap Tester
      G01207019Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE: This pump speed is for the first pump only (in order to close the vacuum valve). After this, the pump speed can be reduced.

      Standard opening pressure  : 83.4-112.8 kPa (0.85-1.15 kgf/cm2 , 12.1-16.4 psi)

      Minimum opening pressure  : 69 kPa (0.7 kgf/cm2 , 10.0 psi)

      NOTE:
      • Use the tester's maximum reading as the opening pressure.
      • If the opening pressure is less than minimum, replace the reservoir cap.
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