engine overheat DATSUN 610 1969 Workshop Manual

CoolIng
System

GENERAL

FAN
BELT
TENSION

FLUSHING
AND
DRAINING
THE
SYSTEM

THERMOSTAT

Testing

RADlA
TOR
Removal

GENERAL

The

cooling
system
is

pressurised
and

incorporates
a

water

pump
corrugated
fin

type
radiator
fan
and
a

pellet
type

thermostat

The
water

pump
is
of
the
centrifugal
type
and
has
an

aluminium
die
cast

body
The
volute
chamber
is
built
into

the

front
cover

assembly
and
a

high
pressure
sealing
mechanism

prevents
water

leakage
and
noise

The
fan

pulley
is
driven

by
the
V
belt
from
a

pulley
on

the
crankshaft

he

pellct
type
thermostat
enables
the

engine
to
warm

up

rapidlY
and
also

regulates
the

temperature
of
the
coolant
When

the
wax

pellet
in
the
thermostat
is
heated
it

expands
and
exerts

pressure
against
a
rubber

diaphragm
causing
the
valve
to

open

and
allow
the
coolant
to
flow
from
the

cylinder
head
back
to

the
radiator

As
the

pellet
is

cooled
itcontractsand
allows
the

spring
to

close
the
valve

thereby
preventing
coolant
from

leaving
the

cylinder
head

The
rad
ator
is
of
the
down

flow
type
with
an

expansion

tank
The
relIef
valve
in
the
radiator
filler

cap
controls
the

pressure
at

approximately
0
9

kg
sq
cm

l3Ib
sq
in
Always

try
to
avoid

removing
the
filler

cap
when
the

engine
is
hot
as

coolant

may
spray
out
and
cause

scalding

If
the

cap
must
be
removed
in
these
circumstances
use
a

lar
e

pic
c
of
cloth
to
hold
the

cap
and
turn

the
cap
sli

htlY

Walt
until
all

pressure
has

been
released
before

lifting
off
the

cap

F
AN
BELT
TENSION

The
fan
belt
drives
the
water

pump
and
alternator
as

well

as

the
fan
and
its
correct

adjustment
is
most

essential
A
loose

fan

belt
will

sl
ip
and

Y
e
r

and
most

probably
cause

overheating

alternatively
If
the
belt
IS
too

tight
the
pump
and
alternator

bearings
will
be
overloaded

The
belt
is

correctly
tensioned
if
it
can
be
depressed

by

approximately
10
mm

1
2
in
at
a

point
midway
between
the

fan
and
alternator
pulleys
See

Fig
R2

If

adjustment
is
neces

ary
slacken
the
alternator

mounting

and

adjustment
bolts
and

pivot
the
alternator

away
from
the

engine
to

tighten
the
belt
to

towards
the

engine
if

the
belt

is

to
be
slackened

NOTE

Always
apply
leverage
to
the
drive
end

housing
when

pivoting
the
alternator
and
never
to
the
diode
end

housing
or
the
alternator
will
be

damaged
Retighten
the
alternator
bolts
and
make
SUfe

that
the
belt

is

correctly
tensioned

FLUSHING
AND
DRAINING
THE
SYSTEM

The
radiator
and
water

passages
should
be
flushed
out

periodically
to
remove
the
accumulated
scale
or
sediment

Reverse

flushing
equipment
should
be
used
to

carry
out
a

completely
thorough
flushing
operation
but
the
owner
drivef

not

possessing
this

type
of

equipment
can
flush
out
the

system

in

the
following
manner

Drain
the
system
by
removing
the
radiator
filler

cap
and

opening
the
radiator
and

cylinder
block
drain

taps
Close
the

taps
again
and
refill
the
radiator
Run

the
engine
for
a
ShOft

period
and
then
rc
open

the
drain
taps
Continue
this

sequence

until
the
water

flowing
from
the

taps
is
clean
then
close
the

taps

and
refill
the
radiator

An
anti
freeze
mixture
should

always
be
used
in
Winter

time
The
Niss3n

long
life
coolant
L
L
c
is
an

ethylene
glycol

solution

containing
a
corrosion

preventative
which
can
remain

in
the
vehicle

throughout
the
year
but
must
not

be
mixed
with

other

products

It
is
advisable
to
check
the
radiator
and
heater
hoses
when

filling
with
anti
freeze
and
renew

them
if

signs
of
deterioration

are

apparent

WATER
PUMP

Replacement

The
water
pump
must
not
be
dismantled
and
should
be

renewed
if
it
becomes

faulty
The

pump
can
be
removed
in
the

following
manner

Drain
the

cooling
system

2
Take
the
fan
belt
off

the
pulley

3
Remove
the
fan
and

pulley

4
Remove

the
retaining
nuts
and
withdraw
the
water

pump

See

Fig
B
3

lnstallation
of

the

pump
is
a

reversal
of
the
removal

procedures

rERMOST
ATTesting

The
thermostat
is
located
in
the
water
outlet

passage

See

Fig
B
4
To
remove
the
unit
drain
the
cooling

system

remove
the
radiator
hose
and
the
water
outlet
elbow
Take
out

the
thermostat

25

CENTRIFUGAL
ADVANCE
MECHANISM

Special
equipment
is

required
to
check
the
advance

characteristics
It
is

possible
however
to

carry
out
an
exam

ination
of

the
caffi

assembly
and
the

weights
and

springs
to

ensure
that
the
earn
is
not

seizing

Lift
off
the
distributor

cap
and
turn
the
rotor
anti
clock

wise
When

the
rotor

is
released
is
should
return
to

the
fully

retarded

position
without

sticking
If
it

does
not
return
to
the

fully
retarded

position
it
will
be

necessary
to
check
for

dirt

and
weak

springs

It
should
be
noted
that

any
wear
in
the

mechanism
or

lose
of

spring
tension
will

upset
the
advance
characteristics
and

cause

unsatisfactory
engine
running
performance
over
the

speed

range

VACUUM
ADVANCE
MECHANISM

The

diaphragm
of
the
vacuum
advance

mechanism
is

mechanically
connected
to
the
contact
breaker

plate
The
rise

and
fall
of
inlet
manifold

depression
causes

the

diaphragm
to

move

the
contact
breaker

plate
to

advance
or

retard
the

ignition

If
the
vacuum

control
unit
fails
to

function

correctly
a

check
can
be
carried
out
to
ensure
that
the
contact
breaker

plate

is

moving
freely
and
that
the

three
steel

balls
at

the

top
and

oottom
of
the

plate
are

adequately
lubricated

Also
make
sure
that
the
vacuum
inlet

pipe
is
not
blocked

or

leaking
and
is

securely
tightened

Leakage
may
be
due
to
a

defective

diaphragm
which

should

be
renewed

along
with

any
other

faulty
part
of
the
mechanism

IGNITION
DlSTRffiUTOR
Removal

and

Dismantling

Disconnect
the

battery
leads

2
Disconnect
the

high
tension
lead
at

the
coil

3
Withdraw

the
high
tension
leads
from
the
distributor

cap

4
Detach
the
suction

pipe
from
the
vacuum
control
unit

5
Mark
the

position
of
the
distributor
and
rotor
remove
the

flange
mounting
bolts

and
withdraw
the
distributor

To
dismantle
the
distributor

proceed
as

follows

Take
off
the
distributor

cap
and
remove

the
rotor

Slacken

the
two
set
screws

holding
the
contact
breaker

upper
plate

Remove
the

primary
cable
terminals
and
withdraw
the
contact

set
from

the
distributor
Fig
C
S
Remove
the
vacuum
control

unit

c
Remove
the
two
screws
and
lift
out
the
contact

breaker

plate
detach
the

clamp
the
terminal
and
the
lead

To
remove
the
cam
take
out
the
centre
screw
as

shown
in

Fig
e
6
Drive
out

the
drive

pinion
retaining
pin
with
a
drift

and
hammer
Fig
e
and
remove
the

pinion
and
washer
Take

care
not
to
stretch
or
deform
the

governor
springs
when

detaching

them
from
the

weights

IGNITION
DISTRIBUTOR

Assembling
and

Installing

Assembly
is
a
reversal
of
the

dismantling
procedure

Lubricate
the

moving
contact

pivot
and
smear
the
lobes
of
the

cam
with
multi

purpose
grease

If

the
centrifugal
advance
mechanism
has
been
dismantled

the

governor
springs
and
cams
must
be
refitted
as

shown
in

Fig
e
8
The

governor
weight

pin
6
should
be
fitted
into

the

longer
of
the
two
slots

leaving
a
certain
amount
of

clearance

for
the
start

and
end
of
the

centrifugal
advance
movement

When

installing
the
distributor
take
care
to

align
the

body

and
rotor

with
the
marks
made
during
removal
The
rotor
must

be

positioned
in
its

original
location
it
will
turn

slightly
when

the
distributor
is
inserted
and
the

gear
teeth
mesh
Remove
and

replace
the
distributor
if

the
rotor
does
not

point
to
the

align

ment

mark
until
both
distributor

body
and
rotor
are
correctly

aligned

SPARKING
PLUGS

The

sparking
plugs
should
be

inspected
and
cleaned
at

regular
intervals
not

exceeding

every
10
000
km
6000
miles

New

sparking
plugs
should
be
fitted
at

approximately
20
000

km
12
000
miles

Remove
the

plugs
and
check
the
amount
of
electrode

wear
and

type
of

deposits
Brown
to

greyish
tan

deposits
with

slight
electrode
wear

indicate
that
the

plugs
are

satisfactory
and

working
in

the
correct
heat

range

Dry
fluffy
carbon

deposits
are
caused

by
too

rich
a
mixture

dirty
air
cleaner
excessive
idling
or

faulty
ignition
In
this

case

it
is
advisable
to

replace
the

plugs
with

plugs
having
a

higher
heat

range
Oily
wet
black

deposits
are
an

indication

of

oil
in

the
combustion
chambers

through
worn

pistons
and

rings
or
excessive
clearance
between
valve

guides
and
stems

The

engine
should
be
overhauled
and
hotter

plugs
installed
A

white
or

light
grey
centre

electrode
and
bluish
burned
side

electrode
indicates

engine
overheating
incorrect

ignition
timing

loose

plugs
low
fuel

pump
pressure
or
incorrect

grade
of
fuel

Colder

sparking
plugs
should
be
fitted

The

plugs
should
be
cleaned
on
a

blasting
machine
and

tested
Dress
the
electrodes
with
a
small
file
so
that
the
surfaces

of
both
electrodes
are
flat
and

parallel
Adjust
the
spark
plug

gap
to
0
8
0
9
mm
0
031
0
035
in

by
bending
the
earth

electrode
Refit
the

plugs
and

tighten
them
to
a

torque
reading

of
1
5
2
5

kgm
II
15Ib
ft

31

N
Engme
SYMPTOMS
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SYMPTOMS

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