Thermostat - Kubota WSM 05 Series Workshop Manual

05
SERIES WSM,
01640
DIESEL ENGlNE
[3] THERMOSTAT
1
d & &
11 790F10210
The thermostat maintains the cooling water at correct
temperature. KUBOTA's engine uses a wax pellet type
thermostat. Wax is enclosed in the pellet. The wax is
solid at low temperatures, but turns liquid at high
temperatures, expands and opens the valve.
(A) At low temperature (lower than 71 "C, 160
O F )
As the thermostat is closed, cooling water circulates
in the engine through the water return pipe without
running to the radiator.
Air in the water jacket escapes to the radiator side
through leak hole
(8)
of the thermostat.
(B) At high temperature (higher than 71 'C,
160
O F )
When the temperature of cooling water exceeds 71
"C
(160
O F ) ,
wax in the pellet turns liquid and expands.
Because the spindle
(4)
is fixed, the pellet
(3)
is lowered,
the valve (2) is separated from the seat (l), and then
cooling water is sent to the radiator.
(2) Valve (7)
Spring
(1) Seat (6) Wax (Solid)
(3)
Pellet
(8) LeakHole
(4) Spindle
(9) Wax (Uquid)
(5) Synthetic Rubber
11790M10182
[4]
RADIATOR
(not included in
the
basic engine)
The radiator core consists of water carrying tubes (2)
and fins (3) at a right angle to the tubes (2). Heat of hot
water in the tubes is radiated from the tube walls and
fins. KUBOTA's engine uses corrugated fin type core
which has a light weight and high heat transfer rate.
Clogging is minimized by the louverless corrugated fins.
(1) Cooling
Air (3) Fin
(2) Tube
I
I790M1
Q
191
M-19