Thermostat Inspection - Yanmar 3YM30 Sevice Manual

2. Inspection and adjustment

2.5 Thermostat inspection

(1) Put the thermostat in a beaker with fresh water, and heat it on an electric stove. The
thermostat is functioning normally if it starts to open between 75-78 deg C, and opens
until 8 mm or more at 90 deg C.
Replace the thermostat if it not functioning normally.
Valve opening
Temperature
(deg C)*
69.5-72.5
* Valve opening temperature is carved on the flange.
(2) Normally, the thermostat should be inspected every 500 hours or operation, but, it
should be inspected before this if the cooling temperature rises abnormally or white
smoke is emitted for a long time after engine starting.
(3) Replace the thermostat every year or 2000 hours of operation (whichever comes first).
Thermometer
Thermostat
Full open lift
(Temperature)
8 or more (85 deg C)
(mm)
45
Thermostat cover
Thermostat
Fresh water pump body