coolant temperature DATSUN PICK-UP 1977 Service Manual

r

ManifolJ
nuts

I

2
to
1
6

kg
m

8
7
to
I

6
ft
lb

Carburelor
nuls

0
5
to
1
0

kg
m

3
6
to
7
2
fl
tb

Fig
ET
7
Tightening
s

quence

CHECKING
ENGINE

OIL

Check
if
oil
is
diluled
with
water

or

gasoline
Drain
and
refill
oil
if

necessary

Notes

a
A

milky
oil
indicates
the

presence

of

cooling
water
Isolate
the
cause

and
take
corrective
measure

b
An
oil
with

extremely
low

viscosity

indicates
dilution
with

gasoline

2
Check
oil
level
If
below
the

specified
level

raise
it

up
10
the
H

level

Engine
oil

capacity

including
oil

filter

Maximum
H
leven

4
3
liters

4

MUS
qt
3
Y

Imp
qt

Minimum
L

level

3
3
liters

3
f
US

qt
2
U

Imp
ql

REPLACING
OIL

FILTER

The
oil
mter
is

a

cartridge
type
and

can
be
removed

using
Oil
Filter

Wrench
STI9320000

I
Check
for
oil
leaks

past
gasketed

flange
If

leakage
is

found

retighten

just
enough
to

stop
leakage
If

retight

ening
is

no

longer
effective

replace

mter
as
an

assembly
Engine
Tune

up

2
When

installing
oil

filter

tighlen

by
hand

Note
Do
not

overtighten
oil

flIt

lest

leakage
should
occur

CHANGING
ENGINE

COOLANT

PERMANENT
ANTI
FREEZE

COOLANT

Permanent
anti

freeze
coolant
is
an

ethylene
glycol
base

producl
conlain

ing
chemical
inhibilors
10

protect
the

cooling
system
against
corrosion

The
anti
freeze
does
not
contain

any

glycerine
ethyl
or
methyl
alcohol

It
will
not

evaporate
or
boil

away
and

can
be
used
with
either

high
or
low

temperaturethennoslat

It

flows

freely
transfers
heat
effi

ciently
and
will

not

clog
passages
in

the

cooling
system

The
anti
freeze
must
not
be
mixed

with
other

products

This
coolant
can
be
used

through

out

the
seasons
of
the

year

Whenever
coolant
is

changed
the

cooling

syslem
should
be
flushed
and

refilled
with
a

new
coolant

Check
the
level
See
the
instruc

lions
furnished

by
the
manufacturer

for
the
mixture
ratio

of
anti
freeze
10

water

CHECKING

COOLING

SYSTEM
HOSES

AND
CONNECTIONS

Check
hoses
and

fittings
for
loose

connections
or
deterioration
Re

tighten
or

replace
if

necessary

INSPECTION
OF

RADIATOR

CAP

Apply
reference

pressure
0
9

kg
cm2
13

psi
1
to
radiator

cap
by

means
of

a

cap
tester
to
see
if
it
is

satisfactory
Replace
cap
assembly
if

necessary

ET
8
Fig
ET
fJ

Teltill
l
rod
ioto

cop

COOLNG
SYSTEM

PRESSURE
TEST

With
radiator

cap
removed

apply

reference

pressure
1

6

kg
cm2
23

psi
to
the

cooling
system
by
means

of
a
lesler
to
detect

any
leakage

Water

capacity

Without
heater

7
4
liters

7
U
US

qt
6
f

Imp
qt

With
heater

8
0
liters

8
f
US

qt
7

Imp
qt

CHECKING
VACUUM

FITTINGS
HOSES

AND
CONNECTIONS

Check
the
condition
of

filtings
and

hoses

Retighten
or

replace
if
neces

sary

All
vacuum
hoses
can
be
identified

by
colors

White
line

Vacuwn
tube
to
carburetor
E

G
R

Tube

Vacuum
tube
to
thermal
vacuum

valve

Thennal
vacuum
valve
to
E
G
R

control
valve

r
EC350

Fig
ET
43

Cleanill
l
E
G
R
control

lJ
Jlue

Thermal
VBCuum
valve

Dismount
thermal
vacuum
valve

from

engine

Note
Before

dismounting
drain
e

gine
coolant
from

engine

Apply
vacuum
to
thermal
vacuum

valve
and
check
to
be
sure
that
ther

mal
vacuum
valve

opens
or
closes
in

response
to

engine
coolant

tempera

lurt
i1
i

iYCl
lt
lt
U

Thermal
vacuum
valve
should

open

at
a

temperature
of
57
to
630C
134

to
1450F

completing
the
vacuum

passage

Note
Do
not
aUow
water
to

get

inside
the
thermal
vacuum
valve

EC
242

Fig
ET
44

Checkill
lthermallXlCuum

valve
Engine
Tune

up

CHECKING

EVAPORATIVE

EMISSION
CONTROL

SYSTEM

Vapor
Rnes
and
fuel

vepor

control
valve

Checking
fuel
tank

vapor

liquid

separator
and

vapor
vent
line

I
Check
all
hoses
and
fuel
tank

roler

cap

2
Disconnect
the

vapor
vent
line

connecting
carbon
canister
to

vapor

liquid
separator

3
Connect
a
3
way
connector
a

manometer
and
a
cock
or
an

equiva

lent
3
way

charge
cock
to

the
end
of

the
vent
line

4

Supply
fresh
air
into
the

vapor

vent
line

through
the

cock
little

by
little
until

pressure
becomes
368

mmH20
14
5
inH20

5

Shut
the
cock

completely
and

leave
it
unattended

6

After
2
5
minutes

measure
the

height
of
the

liquid
in

the
manometer

7

Variation
of

height
should
remain

with
25

mm
l20
0
98
inH20

8
When
filler
cap
does

not
close

completely
the

height
should
drop
to

zero
in

a
short
time

9
I
f
the

height
does
not

drop
to

zero
in

a
short
time
when
filler

cap
is

removed
it
is
the

cause
of
a

stuffy

hose

Note
In

case
the

vent
line

is
stuffy

the
breathing
in

fuel
tank
is
not

thoroughly
made

thl
causing
in

suffICient

delivery
of
fuel
to

engine

or

vapor
lock
It
must
therefore
be

repaired
or

replaced

3
way
connectoT

36
mmH20

14
5
inH20

c

s
I

W

@

Carbon
canister

r

EC786

Fig
ET
45

Checking
evaporative
emission
control

By
tem

Checking
carbon
canister

purge

control

valve

Check
for
fuel

vapor
leakage
in
the

distributor
VC
line
at

diaphragm
of

carhon
canister

purge
control
valve

To
check
for

leakage

proceed
as

follows

1
Disconnect

rubber
hose
in

the

line
between
T
connector
and
carbon

canister
at
T

connector

2
Inhale
air
into

the

opening
of

rubber
hose

running
to
VC
hole
in

carbon
canister
and
ensure
that
there

is

no
leak

ET

22
I

I

L

I

ET349

Fig
ET
46

Checking
carbon
cani
ter

purge
control
valve

r

I

I

PRELIMINARY
CLEANING
AND

INSPECTION

DISASSEMBL
Y

PRELIMINARY

CLEANING
AND

INSt

ECTION

Before

disassembling

engine
note

the

following

I
Fuel

oil
or
water

may
leak

past

cylinder
head
and
block
Prior
to

disassembling
check

cylinder
head

1
1ltermal
vacuum
valve

2
Check

valve

3
Altitude

compensator

in

air
cleaner

4
Air

gallery
pipe

S

Auto
choke

6
Automatic

temperature

control
air

cleaner

7
Anti
8ackfire
valve
A
B

valve

8
Boost
Controlled

Deceleration

Device
Bee
D
D

9
P
c
v

valve

to
Air
relief
valve

11
E

G
R

control
valve

12
B
C
D
D

control
valve
and

solenoid
valve

13

Emergency
air

relief
valve

14
Air

pump
air
cleaner

IS
Carbon
canister

16
Air
control

valve

11
Air

pump
Engine
Mechanical

ENGINE

DISASSEMBLY

CONTENTS

EM
4

EM
4
PISTONS
AND
CONNECTING
RODS

CYLINDER

HE
AD
EM
7

EM
7

front
chain

cover
oil

pan
and
oil

filter

gaskets
lInd
crankshaft
and
water

pump
seals
for

signs
of

leakage
past

their

gasketed
surfaces

2
Check
carburetor
and

fuel

pump

for
condition
fuel
hoses
for

deteriora

tion
cracks

or

leakage
of
fuel

past

their

jointed
or
connected

surfaces

Fig
EM

0
Emiuion
control
devic
s

California
mod
18
E
T366

3
Remove

carburetor
air

cleaner

Remove
fresh

air
duct

Disconnect
hot
air
duct
from

air

cleaner

Disconnect
air

cleaner
to
air

pump

hose
at
air

cleaner

Disconnect
air

cleanef
to
rocker

cover

hose
at
rocker
cover

Disconnect

air
cIeaner

to
air

con

trol

valve
hose
at
air

cleaner
Cali

fornia

models

only
Disconnect
air

cleaner
to
A

B
valve

hose
at
air

cleaner

Disconnect
air

cleaner
to

related

part
vacuum
hoses
at
air

cleaner

Loosen
air

cleaner
band
bolt
and

remove
carburetor
air

cleaner
as

sembly
from

carburetor

4

Plug
up
carburetor
air

horn

to

prevent
entry
of

foreign
matter

5

Remove

alternator
drive

belt

alternator
and

alternator
bracket

EM
4
6

Remove
air

pump
drive

belt
cool

er

compressor
and
idler

pulley
if

so

equipped

7
Remove
starter
motor
from
trans

mission

8

Visually

inspect
cylinder
head

cylinder
block
rocker
C
Ner

front

chain
cover
oil

pan
and
all
other
outer

parts
for
oil
water
and
fuel
leaks

breakage
or

missing
parts
such

as
bolts

and
nuts

9

Check

piping
and
electrical
cir

cuits
for
deterioration

breakage
fit

tings
discontinuity
or
insulation

DISASSEMBLY

To

remove

engine
from
vehicle

refer
to

the
instructions
under
the

Engine
Removal

and
Installation

ER
section

I

Remove
transmission
from

en

gine

2
Remove

clutch

assembly
from

flywheeL

3

Thoroughly
drain

engine
oil
and

coolan
t

by

removing
drain

plugs

Store

engine
oil
and

coolant
if

they

are

to
be

used

again

4
Place

engine
assembly
on

engine

stand

I

Remove

cooling
fan

2

Remove

right
engine

mounting

bracket

3

Remove
oil
filter
with
Oil

Filter

Wrench
STI9320000

4

Remove
oil

pressure
swi

tch

5

Install

engine
attachment
to

cylinder
block

utilizing
bolt

holes
in

alternator

bracket
and

water
drain

hole

6
Set

engine
on
stand

Engine
Attachment

ST05260001

Engine
Stand

ST050I

SOOO

DESCRIPTION

COOLANT
LEVEL

DRAINING
AND
FLUSHING
THE

COOLING
SYSTEM

WATER
PUMP

REMOVAL
AND

INSTALLATION

DISASSEMBLY

INSPECTION
AND
ADJUSTMENT

TORQUE
COUPLING

REMOVAL
AND

INSTALLATION

DESCRIPTION

The

cooling
system
is
of
the
con

ventional

pressure
type
A

centrifugal

pump
installed
on

the

timing
chain

cover
serves
to
circulate
the

coolant

The

pressure
type
radiator
filler

cap

installed
on
the
radiator

operates
the

cooling
system
at

higher
than

atmos

pheric
pressure

The

higher

pressure
raises
the

boiling
point
of
the

coolant
and
in
Cooling
System

COOLING
SYSTEM

CONTENTS

CO
2

CO
2
OISASSEMBL
Y

INSPECTION

TEM
COUPLlNG

INSPECTION

THERMOSTAT

REMOVAL
AND

INSTALLATION

INSPECTION

RADIATOR

REMOVAL
AND

INSTALLATION

INSPECTION
CO
2

CO
2

CO
3

CO
3

CO
3

CO
3

CO
4

creases
the

cooling
efficiency
of

the

radiator

When
the

thermostat
is
closed

the

coolant
remains
in
the

cylinder
head

and

block
for
swift

warming
up
of
the

engine
After
it
reaches

normal

oper

ating

temperature
the

coolant
circu

lates

through
the
radiator

The

cooling
fan

drive
is
of
a

coupling
type

COOLANT

LEVEL

The

coolant
level
should

be
check

ed

and
maintained
at
SO

mm
1
97
in

below

the

upper
face
of
filler

neck

when
the

engine
is
cold
C0055

Fig
CO

I
Cooling

ry
lem

Caution

To
avoid
serious

personal

injury
never
remove
I3diator

cap

quickly
when

engine
is
hot
Sudden

release
of

cooling

system
pressure
is

very

dangerous

CO
2
CO
4

CO
4

CO
4

CO
5

CO
5

CO
5

CO
5

CO
5

CO
5

CO
6

If
it
is

necessary
to
remove
radiator

cap
wben
radiator
is
hot
turn

cap

slowly
counterclockwise

to
the
r

step
After
all

pressure
in
the
cool

ing
system
is
released
tom

cap

passing
the

stop
and
remove
it

DRAINING

AND
FLUSHING

THE

COOLING

SYSTEM

To
drain

the

cooling
system
re

move
radiator

cap
release
drain

cock

at
the
bottom

of
radiator
and
drain

plug
on

the

right
side
of

cylinder

block
If
the

heater

system
is
installed

set
heater

temperature
control
valve
to

open
position
After
the

coolant
is

drained

completely
close
drain

cock

and

plug
and
refill
the

system
with

clean
soft
water

WATER
PUMP

The

water

pump
cooling
fan

pulley

and

torque

coupling
are

a
unitized

construction

The
water

pump
is
of

a

centrifugal

type
which

is
mounted
on
the

engine

front
cover

REMOVAL
AND

INSTALLATION

To

replace
the

torque

coupling

follow
the

same

procedure
as
in
the

water

pump
The

torque
coupling
can

not
be

separated
from
the
water

pump
Cooling
System

DISASSEMBLY

The

torque
coupling
is

so

designed

that
it

can
not
be

disassembled
INSPECTION

Inspect

torque
coupling
for
oil

leakage
If

necessary

replace

TEM

COUPLl
G

For
air
conditioner

equipped
models

Tem
coupling
is

a

type
of
fan

coupling
which
is

provided
with
a

temperature
control

system

The
conventional

coupling

always

slips
the
fan
at

a
high

speed
under

a

constant
ratio

regardless
of

the

engine

cooling

requirement

The

slipping
ratio

of
the
Tern

coupling
however

is

properly
changed

with
the

cooling
requirement

ON
denotes

that

cooling
is
re

quired
and
the
fan

operates
up
to

about

2
150

rpm
When

high

cooling
is

not

required

during
cold
season
with

the

engine
warmed

up
etc
the

oper
w

6
I

1
Bi
metal

thermostat

2

Slide
valve

3
Reserve
chamber

for
OFF

4

Bearing

5

Driving
chamber
for

ON

6

ouplingpart
labyrinth

coon

Fig
CO
5
CrQM
sectional
view

of
Tem
coupling

ation
is

placed
under

OFF
condition

and
the
fan

slips
at
about

1
650

rpm

The
coiled
bimetal
thermostat

installed
on

the
front
center

portion
of

the
Tem

coupling
detects

temperature

of
air

passing

through
the

radiator

The
air

temperature
is

directly

relative
to
the

engine
coolant

tempera

ture
and
the
inside

slide
valve
is

opened
or
closed

as

required
and
thus

the
ON
OFF

control
is

performed

When
the
air

temperature
rises

the

bimetal
is

expanded
and
the

valve
is

opened
silicon
oil
is
forwarded

to
the

groove
that
transmits

torque
and
the

CO
4
system
is

placed
under
ON

con

dition

When
the

valve
closes
silicone
oil
is

not

supplied
to
the

driving
chamber

oil
in

the

driving
chamber
is

accumu

lated
on

periphery
due
to
the

centrif

ugal
force
and
led

into
the
reserve

chamber
Now

oil
is

eliminated
from

the

driving
chamber

and
the

system
is

placed
under
OFF
condition

With
this

system
when
fan

cooling

is
not

required
the

output
loss
is

minimized

and
noise

can
be
far

reduced

Conventional

COUplin9

WATER
PUMP
SPEED

F

Z

Tern

coupling

WATER
PUMP

SPEED

C0029

Fig
CO
6
Characteristic

of

Tern
coupling

INSPECTION

Check
Tem

coupling
for
oil

leakage

or
bend
of
bimetal

If
the
above

symptoms
are
found

replace
it
with

a
new
one
as
an

assembly

THERMOSTAT

A
wax

pellet
type
thermostat
is

mounted
in
the
thermostat

housing
at

the

cylinder
head
water
outlet

The
function
of
the
thermostat
is

to
control
the

flow
of
coolant
facili

tating
fast

engine
warm

up
and

regu

lating
coolant

temperature
The
ther

mostat
is

designed
to

open
and
close
at

predetermined
temperatures
and
if

not

operating
properly
should
be

re

moved
and
tested
as
described
below

REMOVAL
AND

INSTALLATION

I

Drain
coolant

partially

2
Disconnect

upper
radiator
hose
at

water
outlet

3

Remove
bolts

and
remove
water

outlet

gasket
and
thermostat
from

thermostat
housing

Fig
CO
7

Removing
therm06t
t
Cooling
System

4

After
checking
thermostat
re

install
with

a
new

housing
gasket
in

place

5
Reinstall
water

outlet

6

Replenish
coolant
and
check
for

leaks

INSPECTION

A

sticking
thermostat
will

prevent

the

cooling
system
from

functioning

properly
If
the
thermostat
sticks
in

the

open
position
the

engine
warms

up
very
slowly
If
the
thermostat

sticks
in

the
closed

position
over

heating
will
result
Therefore
the
ther
mostat
should
be

inspected
to

make

sure
that
it
is
in

good
condition

1
Measure
coolant
temperature

when
thermostat
valve
starts
to

open

2
Measure
the
maximum
lift

of

thermostat
valve

Fig
CO
S

Impecting
therm06t
t

Temperate
Frigid
Tropical

type

type
iype

Valve

opening

80
5
to
83
5
86
5
to
89
5
75

to
78

temperature

177
to
183
187
to
193

167
to
172

oC
OF

Maximum

valve
lift
8
95
8
1
00
8
90

mm
oC

in
F
0
31
203

0
31
212
0
31

194

If
thermostat
does
not

operate
at

the
above

specified

temperature
it

must
be

replaced
because
it
cannot
be

repaired

RADIATOR

The
radiator
is

a
conventional
down

flow

type
having

top
and

bottom

tanks
to

distribute
the
coolant
flow

uniformly
through
the
vertical
tube
of

radiator
core

The

radiator
filler

cap
is

designed
to

maintain
a

pre
set

pressure
0
9

kg
cm2
13

psi
above

atmospheric

pressure

The
relief
valve

consisting
of

a

blow
off

valve
and
a

vacuum
valve

helps
to

prevent
the
coolant
from

boiling
by
giving

pressure
to
it
How

ever
when

the

pressure
is
reduced

below

atmospheric

pressure
the

vacu

um
valve
allows
air

to
re
enter

the

radiator

preventing
the
formation
of
a

vacuum
in
the

cooling
system

CO
5
On
models

equipped
with
auto

matic
transmission

the
oil
cooler
is

combined
with
the

radiator
to
cool

transmission
fluid

REMOVAL
AND

INSTALLATION

Drain
coolant
into
a
clean
con

tainer

2

Disconnect
radiator

upper
and

lower
hoses
On
models
with
auto

matic
transmissions
disconnect
cooler

inlet
and
outlet
lines
from
radiator

3

Remove
fan
shroud
retaining

bolts
and

remove
fan
shroud

4

Remove
front

grille

5

Remove
radiator
retaining
bolts

and
then

remove
radiator

upward

6
Install
radiator
in
the
reverse
se

quence
of
removal
Note
the
fol

lowing

I
Insert
hoses
in

their

positions

until

they
bottom

2
Ensure
that
arrow
marks
on

hoses
are

clearly
visible
from

upper

Condition

Loss

of
water

Poor
circulation

Corrosion

Overheating

Overcooling
Cooling
System

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Probable
cause

Damaged
radiator
seams

Leaks
at
heater
connections
or

plugs

Leak
at

water

temperature
gauge

Loose

joints

Damaged
cylinder
head

gasket

Cracked

cylinder
block

Cracked

cylinder
head

Loose

cylinder
head

bolts

Restriction
in

system

Insufficient
coolant

Inoperative
water

pump

Loose

fan
belt

Inoperative
thermostat

Excessive

impurity
in

water

Infrequent
flushing
and

draining
of

system

Inoperative
thermostat

Radiator
fin
choked
with
mud
chaff
etc

Incorrect

ignition
and
valve

timing

Dirty
oil
and

sludge
in

engine

Inoperative
water

pump

Loose
fan
belt

Restricted
radiator

Inaccurate

temperature
gauge

Impurity
in

water

Inoperative
thermostat

Inaccurate

temperature
gauge

CO
7
Corrective
action

Repair

Repair

Tigh
ten

Tighten

Replace

Check

engine
oil
for
contamination
and
refill

as

necessary

Replace

Check

engine
oil
in
crankcase
for

mixing

with

water

by
pulling
oil
level

gauge

Replace

Tighten

Check
hoses

for

crimps
and

clear
the

system

of
rust
and

sludge
by
flushing
radiator

Replenish

Replace

Adjust

Replace

Use
soft
clean
water
Rain

water
is
satis

factory

Cooling

system
should
be

drained
and

flushed

periodically
Permanent
anti
freeze

Ethylene
glycol
base
can
be

used

through

out
the

seasons
of
the

year
and

change

periodically
at
intervals
recommended

Replace

Clean
out

air

passage
thoroughly
by
using
air

pressure
from

engine
side
of
radiator

Adjust

Refill

Replace

Adjust

Flush
radiator

Replace

Use
soft
clean
water

Replace

Replace

E
G
R
OFF

operation

When

engine
coolant

temperature

is
low

recirculated
exhaust

gas
causes

irregular
engine

operation
To

prevent
Emission
Control

System

this
recirculation

of
exhaust

gas
must

be
cut
off

for
a
few

minutes
after

engine
has
started
The
thermal
vacu

um
valve

is

provided
for
this

purpose

r
rn

11

L

e

7

E
G
R

controlval
le
clo

2

When

engine
coolant

temperature

is
above

the

working

temperature
of

the
thermal

vacuum
valve

I
The
valve

port
come

to
the

top

J
It
remains

closed
while

engine
coolant

temperature
is
low
and

keeps
the

E
G
R
control
valve
closed

thereby

culling
off
the

E
G
R
circuit

I

lW
jS

1
Throttle
valve

Thermal
vacuum

valve
close

j
Note

m
Vacuum
condition

of
the

throttle
valve
du

ring

engine

idling
for

improved
idling

operation

At

this

point
vacuum
does
not

actuate

the
E
G
R
control
valve

r
T
D

L

t

i

q

II

E
G
R
control

valve

close

2
In
the
full

throttle

driving
posi

tion

the
suction
vacuum

on
the
vacu
JllrI

Thermal
vacuum
valve

ope

um

passage
does

not

surpass
the
vacu

um

required
to

actuate
the
E
G
R

EC
20
EC227

Fig
EC
49
E
G
R
not

actuated

though
intake

manifold

vacuum
is

high
and
E
G
R

control
valve
remain

closed

l

Throttle
valve

EC228

Fig
EC
50

E
G
R
nol

actualed

control

valve

6

Thermal
vacuum
valve

Open

E
G
R
control
valve
Close

E
G
R
ON

operation

The
E
G
R
circuit
is

completed

only
when

engine
coolant

temperature
Emission
Control

System

I

I
Note
Vacuum
condition

EC793

Fig
EC
51
E
G
R
not
actuated

is
above
the

working
temperature
of

the

thermal
vacuum
valve
and
carbu
retor
suction
vacuum
is

large
enough

to

open
the
E
G
R

control
valve

Y
m
l

fj

t1f
1t
3
0

l

P
@
0
f
Y
f

1
i0
W
g

1
i3
iiA
d

m

E
N
ti

n
k

i

l
i
Throttle
valve

n

L
r

E

G
R

control
valve

Open

E
G
R
control
valva

The

E
G
R

control
valve
controls

the

quantity
of
exhaust

gas
to
be
led

to
the

intake
manifold

through
vertical

movement
of
the

taper
valve
connect

ed

to
the

diaphragm
to
which

vacuum
Thermal
vacuum

valve

Open

Note

iiiI
Vacuum
condition

EC794

Fig
EC
52
E
G
R
actuated

is

applied
in

response
to
the

opening

of
the
carburetor
throttle
valve
The

E
G
R
control
valve
is
installed
on
the

E
G
R

passage
through
a

gasket

E
G
R
con
trol
valve
construction

and

type
vary
with

transmission

type
and

car
destination
For
identification

purposes
the

part
number
is

stamped

on
the
recessed

portion
at
the

top
of

the
valve

The

construction
of
the
E
G
R

control
valve
is

shown
below

EC
21

EC350

Fig
EC
65

Cleaning
E

G
R
control

valve

Thermal

vacuum

valve

Dismount
thermal

vacuum
valve

from

engine

Note
Before

dismounting
drain
en

gine
coolant

from

engine

Apply
vacuum
to
thermal
vacuum

valve
and

check
to
be
sure
thaI
ther

mal
vacuum
valve

opens
or
closes
in

response
to

engine
coolant

tempera

ture
as

specified

Thermal
vacuum
valve

should

open

at
a

temperature
of
57
to
630C

135

to
1450F

completing
the

vacuum

passage

Note
Do

not
allow
water
to

get

inside

the
thermal
vacuum
valve

EC242

Fig
EC
66

Checking
hennal

vacuum

valve
Emission
Control

System

CATALYTIC

CONVERTER

DESCRIPTION

The

catalytic
converter
accelerates

the
chemical
reaction
of

hydrocarbons

HC
and
carbon
monoxide
CO
in

the

exhaust

gas
and

changes
them
into

non
harmful

carbon
dioxide

C02

OPERATION

Exhaust

gas
emitted

from
the
en

gine
contains

some
harmful
substances

due
to

incomplete
combustion
in
the

combustion
chamber
The

air

injection

system
is

designed
to

reduce
the
con

tent
of
such
substances
in

the
exhaust

gas
In

this

system
the

secondary
air

is

led
from
the
check
valve

and

injected

into
the

exhaust
manifold

With
this

injection
of
the

secondary
air

hydro

EC444

EC
26
and
water

H20
This
chemical
reac

tion

process
requires
the

proper
a

mount

of
air

which
is

supplied
by
the

air

pump
Refer
to

the
item
AJ

S

This
air
is
caUed

secondary
air

The

catalytic
converter
is
mounted

on
the

vehicles
destined

for
California
Refer

to

Figure
EC
67

3
4

1
Front
tube

2

Catalyti
converter

3
Center
tube
4
Main
muffler

5
Rear
tube

EC782

Fig
EC
67

Location

of
catalytic
converter

car

ons

He
and
carbon

monoxide

CO
in
the
exhaust

gas
are

gradually

oxidized
with

oxygen
02
in
the

secondary
air
and
converted

into
non

harmful
carbon

dioxide

C02
and

water

H20

The

catalytic
converter

further

cleans

engine
exhaust

gas
Through

catalytic
action
it

changes
residual

hydrocarbons
and
carbon
monoxide

contained

in
exhaust

gas
into
carbon

dioxide

and
water
before

exhaust

gas

is

discharged
to
the

atmosphere

c
Secondary
air

Carbon
monoxide

hydrocarbon

Carbon
dioxide
gas

water

F
EC
68

Operution
of
catalytic
corwerter