Cooling System: Inspection

INSPECT THERMOSTAT

HINT:

The valve opening temperature is inscribed on the thermostat.

Fig 1: Identifying Valve Opening Temperature On Thermostat

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Immerse the thermostat in water, then gradually heat the water.

Fig 2: Immersing Thermostat In Water
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Check 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.

Inspect the valve lift.

Valve lift:

TEMPERATURE AND VALVE LIFT SPECIFICATIONS

Temperature	Valve lift
95° C (205° F)	8.5 mm (0.335 in.) or more

If the valve lift is not as specified, replace the thermostat.

Fig 3: Inspecting Valve Lift

Check that the valve is fully closed when the thermostat is at low temperatures (below 77°C (171 °F)).

If not fully closed, replace the thermostat.

INSPECT RADIATOR CAP SUB-ASSY
NOTE:
- If the radiator 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 30° or more above the horizontal.
1. Using a radiator cap tester, slowly pump the tester, then check that air is coming from the vacuum valve.
  Pumping speed: 1 push/3 seconds or more
  
  NOTE: Push the pump at a constant speed.
  
  If air does not come from the vacuum valve, replace the radiator cap.
2. Pump the tester and measure the relief valve opening pressure.
  Pumping speed: 1 push within 1 second
  
  NOTE: The above pumping speed is for the first pumping only (in order to close the vacuum valve). After the first pumping, the pumping speed can be reduced.
  - Standard opening pressure: 93 to 123 kPa (0.95 to 1.25 kgf/cm ² , 13.5 to 17.8 psi)
  - Minimum opening pressure: 78 kPa (0.8 kgf/cm ² , 11.3 psi)
If the opening pressure is less than minimum, replace the radiator cap.

HINT:

Use the tester's maximum reading as the opening pressure.
INSPECT WATER PUMP ASSY
1. Visually check the drain hole for coolant leakage.
  If leakage is found, replace the water pump.
2. Turn the pulley, and check that the water pump bearing moves smoothly and does not make a noise.
If necessary, replace the water pump.

Fig 4: Checking Water Pump Bearing Moves Smoothly Turning Pulley
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002