6.2.4. Thermostat General descriptions and main data The thermostat maintains a constant temperature of coolant (90 ~ 95 °C) To radiator and improves thermal efficiency of the engine by preventing heat loss. Namely, when the temperature of coolant is low, the thermostat valve is closed to make the coolant bypass to Bypass valve directly enter the water pump; when From cooling water pipe To bypass tube the coolant temperature rises to open wide the thermostat valve, the bypass EAMC002I circuit is closed and the water pas- sage to the radiator is opened so that the coolant is forced to flow into the radiator. NOTE : One is named by 71 °C type and the other is 83 °C.
Inspecting There are 2 kinds of thermostats according to surrounding and operating conditions. (1) Check the wax pallet and spring (2) Put the thermostat in a container for damage. 측정자 온도계 Ruler of water, then heat the water slow- Thermometer ly and check temperature with a thermometer. If the valve lift is 0.1 나무판 Woodplate mm (starting to open) at tempera- ture of 83 °C and 8 mm or more (opening wide) at temperature of EFM2055I 95 °C, the thermostat is normal. - 154 - MAINTENANCE OF MAJOR COMPONENTS Item Specification In moderate climates In tropical climates Type Wax-pallet type Wax-pallet type Open at 83 °C 71 °C Open wide at 95 °C 85 °C Valve lift 8 mm or more Truck : 8 mm or more