Cooling System Description; Radiator - Toyota 3b Repair Manual

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COOLING SYSTEM
-
Description
I
DESCRIPTION
This engine utilizes
a
pressurized water forced circulation cooling system which includes
a
thermostat
equipped
with
a
bypass
valve mounted on the outlet
side.
To
Radiator
Thermostat
From Radiator
Water Pump
OilCooler
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The cooling system is
composed
of the
water
jacket (inside the cylinder block and cylinder
head),
radiator,
water pump,
thermostat, cooling
fan,
hoses and other components.
Coolant
which is
heated
in the
water jacket
is
pumped to the radiator, where the cooling fan
and
the vehicle airstream as it passes through. Coolant
which
has been cooled
is then sent
back
to
the
engine by the water pump, where
it
cools the
engine.
The
water jacket
is a network of channels in the
shell
of
the
cylinder block
and cylinder
head
through which coolant
passes.
lt
is
designed to
provide adequate cooling
of the
cylinders
and
combustion chambers
which
become
the
hottest
during engine operation.
RADIATOR
The radiator performs the
function
of cooling the
coolant which has passed through the water jacket
and become hot, and is mounted in the front
of the
vehicle. The radiator consists of an upper tank
and
lower tank, and
a
core
which
connects
the
two
tanks. The upper tank contains the inlet for coolant
from the water jacket and, depending on the
model,
a
hole
for replenishing water.
lt
also has
a
hose
attached through
which
excess coolant
or
steam
can flow. The lower tank contains the
outlet for
coolant and the drain
cock.
The core contains many
tubes through which coolant flows from the
upper
tank to the lower tank
as
well
as
cooling fins which
radiate heat away from the coolant
in the
tubes.
Coolant
which
has passed
through the water jacket
and become hot is cooled
in this part
by
the
air
sucked
in
by the
cooling
fan and by the
wind
generated
by the
vehicle's travel. Models with
automatic transmissions include
an
automatic
transmission fluid cooler built into the lower tank
of
the radiator.
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