Thermostat and Radiator Cap Inspection

INSPECTION
1. THERMOSTAT





HINT: The thermostat is numbered with the valve opening temperature.





a. Immerse the thermostat in water and gradually heat the water.
b. Check the valve opening temperature.
Valve opening temperature: 80 - 84°C (176 - 183°F)
If the valve opening temperature is not as specified, replace the thermostat.





c. Check the valve lift.
Valve lift: 10 mm (0.394 inch) or more at 95°C (203°F)
If the valve lift is not as specified, replace the thermostat.
d. 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.





2. WATER OUTLET CAP SUB-ASSEMBLY

NOTICE:
^ 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., keep the tester at an angle of over 30° above the horizontal.

a. 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)

NOTICE: Push the pump at a constant speed.

If air is not coming from the vacuum valve, replace the reservoir cap.
b. Pump the tester and measure the relief valve opening pressure.
Pump speed: 1 push within 1 second

NOTICE: This pump speed is for the first pump only (in order to close the vacuum valve). After this, the pump speed can be reduced.

Standard opening pressure: 83.4 - 112.8 kPa (0.85 - 1.15 kgf/cm2, 12.1 - 16.4 psi)
Minimum opening pressure: 69 kPa (0.7 kgf/cm2, 10.0 psi)

HINT:
^ Use the tester's maximum reading as the opening pressure.
^ If the opening pressure is less than minimum, replace the reservoir cap.