(a) Cold Engine
Upper Radiator Hose
4. Bypass Pipe
¢:J: Low temperature
¢:J: High temperature
5. Lower Radiator Hose
6. Cylinder Head
(b) Normal Operating Temperature
(c) Hot Engine
gradually raise the temperature of the water whi Ie
stirring the water gently.
Valve Opening Temperature Measurement
Watch the valve. As soon as the valve starts to open,
note the temperature.
should be within the range
specified in Table H85. If it is out of the service limit,
replace the thermostat.
Valve Opening Temperature
Continue heating until the water temperature is 95°C
(203° F), and hold the water at the temperature for five
minutes. Then measure the bypass valve height. The
difference between the two bypass valve heights, mea·
sured at room temperature and at 95°C (203°F), is the
full valve lift. If it is less than the service limit, replace
Bypass Valve Height
The bypass valve height difference is the valve lift.