Thermostat; Radiator - Kubota WG972-E2 Workshop Manual

WG972-E2, DF972-E2, WSM

[4] THERMOSTAT

[5] RADIATOR

The thermostat is of the wax pellet type.
The thermostat controls the flow of the coolant to the
radiator to keep the proper temperature.
The case (1), which serves as a valve seat (1), has a
spindle inserted in the pellet (3) which is installed to the
valve (2). The spindle is covered with the synthetic
rubber (5) in the pellet.
The wax is charged between the pellet and the rubber.
■ At low temperature (lower than 71 °C)
The valve (2) is seated by the spring (7) and the
coolant circulates in the engine through the water return
hose without running into the radiator.
Only the air in the water jacket escapes to the radiator
through the leak hole (8) of the thermostat.
■ At high temperature (higher than 85 °C)
As the coolant temperature rises, the wax in the pellet
(3) turns liquid and expands, repelling the spindle, which
causes the pellet to lower.
The valve (2) opens to send the coolant to the radiator.
(1) Seat
(2) Valve
(3) Pellet
(4) Spindle
(5) Synthetic Rubber
The radiator core consists of coolant carrying tubes
(1) and fins (2) meeting at a right angle with the tubes.
The fin is a louverless, corrugated type which is light in
weight, high in heat exchange ratio and less apt to clog.
The coolant in the tubes is cooled by the air flowing
through the tube walls and fins.
(1) Tube
(2) Fin
M-12
GASOLINE / LPG ENGINE
(6) Wax (Solid)
(7) Spring
(8) Leak Hole
(9) Wax (liquid)
W1234567
A : Cooling Air
KiSC issued 01, 2006 A