Section 161 (Engine Cooling System): Inspection

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

INSPECT THERMOSTAT
HINT:

The thermostat is numbered with the valve opening temperature.

Fig 1: Identifying Thermostat
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Immerse the thermostat in water and gradually heat the water.
2. 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.
  
  Fig 2: Inspecting Thermostat
  Courtesy 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
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT WATER OUTLET CAP SUB-ASSEMBLY
NOTE:
- If the radiator cap has contaminations, 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: 1 push/3 seconds or more
  
  NOTE: Push the pump at a constant speed.
  
  If air is not coming from the vacuum valve, replace the radiator cap.
  
  Fig 4: Testing Radiator Cap
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Pump the tester and measure the relief valve opening pressure.
  Pump speed: 1 push within 1 second
NOTE: The following 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)

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 ASSEMBLY
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 noise.
If necessary, replace the water pump.