Cooling System (2ZZ-GE): Inspection

THERMOSTAT
HINT:

The valve opening temperature is inscribed on the thermostat.

Fig 1: Identifying Valve Opening Temperature
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Immerse the thermostat in water, then 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: Checking Valve Opening Temperature Of The 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 fully closed, replace the thermostat.
RADIATOR CAP SUB-ASSY

Fig 3: Checking Valve Lift
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOTE:
- If the radiator cap is contaminated, rinse it with water.
- Before using a radiator cap tester, wet the relief valve and pressure the 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 and check that air comes from the vacuum valve.
  Pumping speed: 1 push every 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.
  
  Fig 4: Checking Radiator Cap Function
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Pump the tester, then 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.

HINT:

Use the tester's maximum reading as the opening pressure.

Standard opening pressure:

74 to 103 kPa (0.75 to 1.05 kgf/cm ² , 10.7 to 14.9 psi) Minimum opening pressure:

59 kPa (0.6 kgf/cm2, 8.6 psi)

If the opening pressure is less than minimum, replace the radiator cap.