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Cooling System: Inspection

  1. INSPECT THERMOSTAT

    HINT:

    The thermostat is stamped with the valve opening temperature.

    Fig 1: Inspecting Thermostat
    G02997688Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Immerse the thermostat in water and gradually heat the water.
    2. Check the valve opening temperature.
      1. Valve opening temperature: 
      2. 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
      G02997689Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the valve lift.
      1. 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.

    4. Check that the valve is fully closed when the thermostat is at low temperatures (below 40°C (104°F)).

      If not closed, replace the thermostat.

      Fig 3: Checking Valve Lift
      G02997690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. INSPECT RADIATOR CAP SUB-ASSY 
    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) on the following page, 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 being released from the vacuum valve.
      Fig 4: Measuring Relief Valve Opening Pressure
      G02997691Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Pump speed: 1 push every 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.
      1. Pump speed: 1 push within 1 second 
    NOTE: The pump speed above should be followed for the first pump only. It will close the vacuum valve. Once the vacuum valve is closed, the pump speed can be reduced.
    1. Standard opening pressure: 
    2. 93 to 123 kPa (0.95 to 1.25 kgf/cm 2  , 13.5 to 17.8 psi) 
    3. Minimum opening pressure: 
    4. 78 kPa (0.78 kgf/cm 2  , 11.4 psi) 

    HINT:

    Pay attention to the tester's maximum reading of the opening pressure. If the maximum reading is less than the minimum opening pressure above, replace the reservoir cap.



  1. INSPECT RELAY (Marking: FAN) 
    1. Remove the FAN relay from the FL block
    2. Measure the resistance of the relay.
    STANDARD SPECIFICATION

    Tester Connection Specified Condition
    3-5 10 kQ or higher
    3-5 Below 1 Q (when battery voltage is applied to terminals 1 and 2)

    If the result is not as specified, replace the relay.

    Fig 1: Measuring Resistance Relay
    G02997696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. INSPECT ECT SWITCH 
    1. Measure the resistance of the switch.
    STANDARD SPECIFICATION

    Temperature Specified Condition
    Above 98° C (208° F) Below 1 Q
    Below 88° C (190° F) 10 kQ or higher

    If the result is not as specified, replace the switch.

    Fig 2: Measuring resistance of switch
    G02997697Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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