MG MGB User Manual

THE COOLING
SYSTEM
C
GENERAL
DESCRIPTION
The cooling
system
is
pressurized
and the
water
circulation
is
assisted
by
a pump
attached
to
the
front of
the
engine
and driven by
a
belt
from the crankshaft
pulley.
A
relief
valve
is
incorporated
into
the radiator filler
cap
which
controls the
pressure.
The
water
circulates
from the
base of the
radiator
and
passes
round the
cylinders
and
cylinder
head,
reaching
the
header
tank of the radiator
via
the thermostat
and
top
hose.
From the header
tank
it
passes
down the
radiator
core
to
the
base tank
of the
radiator.
Air is
drawn through
the
radiator by
a
fan attached
to
the
water
pump
pulley.
Section C.l
LUBRICATION
Early
cars
Remove the
plug from the
water
pump
body and add
a
small
quantity
of
one
of the recommended
greases.
Do
not
pressure-lubricate
the
water
pump or
the seal
may
be
damaged.
Later
ears
The
greasing
plug has been
deleted from the
water
pump
as
no
lubrication
is
necessary.
Section C.2
THERMOSTAT
IMPORTANT—In
hot climates where the
thermostat
is
removed
as a
permanent
measure,
it is essential that
a
thermostat blanking sleeve
is
fitted.
Failure
to
fit
a
sleeve
will result
in
higher
operating
temperatures
and possible
damage.
Removing
1.
Drain the
cooling
system—Section
C4.
2.
Disconnect the radiator
top
hose
from
the
water
outlet elbow. Unscrew the three
retaining
nuts,
detach
the
water
outlet elbow and
joint
washer
and withdraw
the
thermostat.
Inspection
3.
Examine
the thermostat for
damage
and
check
that
the
valve
is in
the closed
position. Renew
the
thermostat if damaged
or
if
the
valve
is
open.
4.
Immerse
the thermostat
in
water
heated
to
the
temperature
marked
on
the thermostat; the
valve will
start
to
open
if
it is
functioning
correctly.
If
the valve
fails
to
open renew
the
thermostat.
Refitting
5. Reverse
the
removing
procedure
using
a new
joint
washer, then re■ll the cooling
system.
MGB. Issue6.
80619
‘
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Fig.
CI
The engine drain
tap
on
the
right-hand
side of the
engine,
later
cars
have
a
drain plug
Section
C.3
TEMPERATURE
GAUGE
A
temperature
gauge
unit, consisting
of
a
thermal
transmitter
and dial indicator,
is
fitted
to
the
vehicle. The
thermal
transmitter is
held
in
the
cylinder
head
at
the
base
of the
thermostat housing
by
a
gland
nut.
The
dial indicator
is
situated
in
the
instrument panel and
is
connected
to
the
transmitter
by
a
capillary
tube.
If the
unit
fails
to
register
the
water temperature,
check
the
thermal
transmitter
and dial indicator
by substitution.
Cars
built
to
certain
specifications
are
■tted
with electrical
temperature
gauges.
Section C.4
DRAINING, F
LUSHING
AND REFILLING
THE
COOLING
SYSTEM
Removing the filler
cap
The
cooling
system
is
under
pressure
while
the
engine
is
hot,
and
the
radiator
■ller
cap
must
be
removed
very
carefully
or
left
in position until the
water
has cooled.
If
it is
necessary
to
remove
the
filler
cap
when the
engine is
hot
it is
absolutely
essential
to
release the
cap
gradually,
and the filler
spout
is
provided with
a
specially shaped
cam
to
enable this
to
be done easily.
Unscrew
the
cap
slowly until the
retaining
tongues
are
felt
to
engage
the
small lobes
on
the
end of the filler
spout
cam,
and
wait
until the
pressure
in
the
radiator
is
fully released
before
■nally
removing
the
cap.
It
is
advisable
to
protect
the hand
against
escaping
steam
while
removing
the
cap.
Draining
the
cooling
system
EARLY
CARS
Open the
two
drain
taps,
one
at
the
rear
of
the
engine
cylinder
block
on
the
right-hand side, the
other
at
the
base
C.S

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English