Engine Cooling System: Thermostat: Inspection
- Check for leaks.CAUTION:
- The engine coolant is pressurized when it is hot. Wait until engine coolant cools down before proceeding the work.
- If the engine coolant splashes, completely remove and clean it.
- Remove the radiator cap.
- Fill the radiator with engine coolant, and then install the radiator cap tester to the filler neck of radiator.CAUTION: Be careful not to deform the filler neck of radiator when installing and removing the radiator cap tester.
- Apply a pressure of 157 kPa (1.6 kg/cm2
, 23 psi) to the radiator and check the following points:
- Leakage from the flow path of the engine coolant or its vicinity
- Significant pressure drop
CAUTION: Be careful of engine coolant from spurting out when removing the radiator cap tester.
- Check that there is no deformation, cracks or other damages.
- Check that the thermostat valve closes completely at an ambient temperature.
- Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and check the temperature and the valve lift amount when the valve begins to open and when the valve is fully opened. Replace the thermostat if faulty.NOTE:
- During the test, agitate the water for even temperature distribution.
- Leave the thermostat in the boiling water for five minutes or more before measuring the valve lift.
- Hold the thermostat with a wire or the like to avoid contacting with container bottom.
Starting temperature to open:
Engine side.
86 - 90°C (187 - 196°F)
Water tank pipe side.
48 - 52°C (118 - 126°F)
Full open temperature:
Engine side.
95°C (203°F)
Water tank pipe side.
63°C (145°F)
Total valve lift:
Engine side.
8.0 mm (0.315 in) or more
Water tank pipe side.
6.0 mm (0.236 in) or more