Installation Instructions
B1700·B21 00·B2400 WSM, 11770
(2)
Thermostat
1 ENGINE
C042F048
(1) Seat
(2) Valve
(3)
Pellet
(4) Spindle
(5)
Synthetic
Rubber
(3)
Radiator
C042F049
(6)
Wax
(solid)
(7) Spring
(8) Leak Hole
(9)
Wax
(liquid)
9
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
temperatures (lower than
82°C
(180°F».
As
the
thermostat
is
closed, cool ing
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
(6)
of
the thermostat.
(B)
At
high temperatures (higher than
82°C
(180°F».
When the temperature
of
cooling water
exceeds
82°C
(180°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
(1),
and then cooling water
is
sent
to
the radiator.
The
radiator core
consists
of
water
carrying tubes
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 ligl1t
weight
and high heat transfer
rate.
Clogging
is
minimized
by
the
louverless
corrugated fins.
0076F014
(4)
Radiator
Cap
C042F050
(1) Cooling
Air
(2) Tube
(3)
Fin
(4) Louverless
Corrugated
Fin
(5) Louvered
Corrugated
Fin
The radiator cap
is
for
sustaining
the
internal
pressure
of
the cooling
system
at
the
specified level
88
kPa
(0.9
kgf/cm
2
,
13
psi)
when
the
engine
is
in
operation.
The
cap
consists
of
a pressure valve
(1)
a
vacuum valve
(2),
valve springs, gasket, etc.
Cooling water
is
pressurized
by
thermal expansion
of
steam, and
as
its
boiling
temperature
rises,
generation
of
air bubbles
will
be
suppressed.
(Air
bubbles in cooling water lowers the cooling effect.)
[A]
When
radiator
internal
pressure is
high
[B]
When
radiator
internal
pressure is
negative
[A]
0011
F033
[8]
0011F034
(1) Pressure Valve
1-M
11
(2) Vacuum Valve