1979 DATSUN 210 check engine

Condition

Faulty

connecting

rod

Faulty
crankshaft

bearing
Engine
Mechanical

Probable

cause

Shortage
of

engine
oil

Low
oil

pressure

Poor

engine
oil

quality

Rough
crankshaft
surface

Clogged
oil

passage

Bearing
worn
or
eccentric

Bearing
improperly
assembled

Loose

bearing

Incorrect

connecting
rod

alignment

Shortage
of

engine
oil

Low
oil

pressure

Poor

quality
engine
oil

Worn

or
out
of
round
crankshaft

journal

Clogged
oil

passage
in
crankshaft

Bearing
worn
or
eccentric

Bearing

inproperly
assembled

Non
co
centric
crankshaft

or

bearing

EM
33
Corrective
action

Add
or

replace
oil

Check
oil
level
on

daily
basis

Correct

Use

proper
oil

Grind
and

replace
bearing

Clean

Replace

Repair

Replace

Repair
or

replace

Add
or

replace

Check
oil
level
on
daily
basis

Adjust

Use

proper
oil

Repair

Clean

Replace

Repair

Replace

OIL

PUMP

The
oil

pump
and
filter

assembly
is

bolted
to

the

right
side

of
the

cylinder

block
and
can
be
removed

with
the

engine
in

pl
c
The
oil

pump
which
is

driven

by
a

gear
on
the
camshaft

has

the

full
flow

element

type
filter
in

stalled
to
the

oil

pump
cover

REMOVAL

I

Place
a
suitable
container

under

oil

pump

2
Remove
three

bolts

attaching
oil

pump
and
filter

assembly
and

with

draw

assembly

3

Separate
oil

filter
from
oil

pump

4

Ciean
off
old

gasket
from

mating

surfaces

i

E

L043

F
EL

2
R

moving
Oil

Pump

Asso

mbly

INSTALLATION

I

Install
oil
filter
to
oil

pump

2

Locate
oil

pump
and

filter
as

sembly
or

cylinder
block

using
a

spacer
and
new

gasket
Secure
with

three

bolts

l
l
Tightening

torque

Oil

pump
securing
bolts

0
9
to
1
4

kg
m

6
5
to
10
1
ft

lbl

3

Check
oil
level

and
add
oil
if

necessary

4

Start

engine
and

check
for
oil

leaks

5

Remove
the
container
Engine
Lubrication

System

DISASSEMBLY
AND

ASSEMBLY

I

Remove
bolt

securing

pump
cover

to

pump

body
Separate
pump
cover

from

pump
body

2

Slide
out
outer
rotor

from

pump

body

3

Remove
oil

pressure

regulator

plug
washer

shim

spring
and
valve

4

Assemble
oil

pump
in
reverse

order
of

disassembly

Note

a

When

placing
oil

pump
in

a
vice

use
extreme
care
not
to
distort

pump
body
and
cover
in
the

jaws

b
Do

not

pull
out

drive
shaft

pin

securing
drive
shaft

and
inner
rotor

Shaft
is

press
fitted
to
rotor
with

the

pin
caulked

EL044

Fig
EL
3
Oil

Pump

l
l
Tightening

torque

Oil

pump
cove
bolt

0
39

to
0

5
2

kltm

2
8

to
3
8

ti
Ib

Regulator
valve

plug

4
0
to
5
0

kltm

29
to
36
ft

bl
INSPECTION

Wash
all

parts
in

cleaning
solvent

and

dry
wiih

compressed
air

I

hispect
pump
body
and

cover

for
cracks
or
excessive
wear

2

Inspect
pump
rotors
for

excessive

wear

3
Check
inner

rotor
shaft
for

looseness
in

pump
body

4

Inspect
regulator
valve
for
wear

or

scoring

5
Check

regulator

spring
to

see
that

it
is

not
worn
on
its

side
or

collapsed

6

Using
a
feeler
gauge
check

tip

clearance

00
and
outer
rotor
to

body

clearance

CD
shown
in

Fig
EL
4

EL059

1
Outer
rotor
to

body
clearance

2

Tip
clearance

3

Gap
between

rotor
and

stnight
edge

4

Gap
between

body
and

straight
edge

ig
EL
4

Checking
Rotor

Clea
nce

7

Place
a

straight
edge
across
the

face
of

pU
mp
and

depress
it

slightly
as

shown
in

Fig
EL
4

Check

gap

@

between

body
and

straight
edge
or

gap

@
between
rotor
and

straight
edge

Gap

0
03
to
0
06
mm

0
0012
to
0
0024
in

Rotor
side
clearance
rotor
to
bot

tom

cover
clearance
with

gasket

should

satisfy
the

specifications

Standard
Wear
limit

Rotor

side
clearance

mm
in
0

04
to
0
08

rotor
to
bottom

cover

0
0016
to
0
031
0
20
0

0079

Rotor

tip
clearance

V
mm
in
Less
than

0
20
0
0079

0
12
0
0047

Outer
rotor
to

body

mm
in
0

15
to
0
21

0
50
0
0197

clearance

CD
0
0059
to
0
083

EL3

Not

Pump
rotors
and

body
are
not
serv

iced

separatdy
If

pump
rotors
or

body
are

damaged
or

worn

replace

ment
of
the
entire
oil

pump
assembly

isnecessary

OIL
PRESSURE

REGULATOR
VALVE

The
oil

pressure
regulator
valve
is

not

adjustable
At
the
released

posi

tion
the
valve

permits
the
oil
to

by

pass
through
the

passage
in
the

pump
cover
to
the
inlet
side
of

the

pump
Check

regulator
valve

spring
to

ensure

that

spring
tension
is
correct

no

1

Regulator
valve

2
Relief

valve

3
Valve

spring
E
L045

Fig
EL
5

Regulator
and
Reli
Vatv
Engine
Lubrication
System

8Peciflcatlons

Oil

pressure

At

idling

more
than

O

Blrg
an2
11

psi

At

3
000

rpm

3
B
to
5
2lrg

an2

54
to
74

psi

Regulator
ai

spring

Free

length

43
49
rom
1
7122
in

InstoJlod
l

ngth
load

30
3
mm
3
67

kg

1
193

inJB
09lbl

Regulator
val

o

ning
pressur

3

8
to
4
2

lrg
an2

54
1060

psi

OIL
PRESSURE

RELIEF
VALVE

The
relief
valve
located
in

the
oil

pump
cover

by
passes
the

oil
into
the

main
oil

gallery
when

the
oil
filter

elem
nt
is

exCessively
clogged
With

regula
tor
valve
removed
check
valve

for

operation
See

Fig
EL
5

OIL
FILTER

tEMOVAL

Place
a
suitable
container
under
the

f1lter

Unscrew
f1lter
from
oil

pump
cover

flange
using
Oil
Filter
Wrench

STl9320000

EL
4
Fig
EL
6

Removing
Oil
Filter

INSTALLAnON

I
Coat

the

packing
on
the
new

f1lter
with

oil
Position
the

f1lter
on

the
oil

pump
cover

flange
Hand

tight

en
the
f11ter
until
the

packing
contacts

the

cover

flange
then
advance
it

2
3

tum

Note
Do
not

overtighten
the
fiIter

or

oil
leak

may
occur

2

Operate
the

engine
at
fast
idle

and
check
for
oil
leaks
Check
the
oil

level
and
add
oil
if

necessary

OIL
PRESSURE

WARNING

SWITCIt

The
oil

pressure
warning
switch
is

located

on
the

oil

pump
cover
and

wired
to

an
instrument

cluster
See

Fig
EL
6

The

warning

light
glows
whenever

the

oil

pressure
drops
below
0

2
to
0
4

kg
cm1
2
8
to
5
7

psi

Prior
to

installing
a
switch
to
cover
I

be

sure
to

apply
a
conductive
sealer

to

threads
of

switch

2
Loosen

belt
then
remove
fan

blade
from

torque
coupling
and

torque
coupling
and

pulley
from

hub

Air

conditioning
system
equipped

models

only

4
Remove

pump
assembly
and

gas

ket
from
front
cover

C0051

Fig
CO
3

Removing
Water

Pump

INSTALLATION

1
Be
sure
to
clean
the

gasket
sur

faces
in
contact
with

pU
flP
and
front

cover

Always
use
new

gaskets
when

installing
pump
assembly
Be

sure
to

tighten
bolts

i
l
Tightening

torque

Water

pump

securing
bolts

0
9
to
1
4

kg
m

6
5
to
10
1
ft
Ib

2
Fill

cooling
system
and

check
for

leaks
at

pump

3

InstaD
fan

pulley

spacer
or

torque

coupling
and

fan
blade

and

tighten
attaching
bolts

securely
Install

belt

and

adjust
for

specified
tension

4

Operate
the

engine
at

fast
idle

and

re

Check
for
leaks

S

Install
fan

shroud

Note

Ensure
that
clearance
between

shroud
and
fan
even
at

any

place

DISASSEMBLY

Water

pump
should
not
be
disas

sembled
Cooling

System

INSPECTION

Inspect
pump
assembly
for
the

following
conditions
and

replace
if

necessary

I

Badly
rusted

or
corroded

body

assembly
and
vane

2
Excessive
end

play
or

roughness

of

bearings
in

operation

Note
If

excessive
mechanical
seal

squeak
occurs
when

engine
is
mn

ning
use
suitable
water

pump
seal

lubricant
to

prevent
squeak

ADJUSTMENT

Check
belt
deflection
between

alternator
and

fan

pulley
by
a

force
of

10

kg
22
Ib

Fan
belt
deflection

8
to
12

mm

0
31
to
0
47
in

If

adjustment
is

necessary
loosen

bolt

retaining
alternator

adjusting
bar

to
alternator
Move
alternator
toward

or

away
from

engine
until
the

correct

tension
is

obtained

TORQUE
COUPLING

The

torque
coupling
keeps
the
fan

speed
at
2
900

rpm
rated

or
below
to

conserve

horsepower
at

high

engine

speed
It
also

helps
reduce
fan
noise
to

a
minimum

during
high
speed
opera

tion

This
unit
is
filled
with
a

special

silicone
oil
used

as
a
fluid

coupling

which
controls
the

fan

speed
Silicone

oil

can
not
be

replenished

The

torque
coupling
is
installed

only
on
the
model

equipped
with
the

air

conditioning
system
In
this
case

use
7
x
350
mm

13
78
in
diam

eter

cooling
fan

CO
3
C0052
t
Wheel

2
Disc

3

Bearing

Fig
CO

4

Torque
Coupling

REMOVAL

Lousen
fan

belt

2
Remove

fan
blade
from

torque

coupling

3
Remove

torque

coupling
from

pulley
and
water

pump
hub

by
re

moving
securing
nuts

INSTALLATION

I
InstaD
the

torque
coupling
in
the

reverse
order
of
removal

2
Install
belt
and

adjust
belt

ten

sian

DISASSEMBLY

The

torque
coupling
is
so

designed

that

it
can
not
be

disassembled

INSPECTION

Inspect
torque

coupling
for
oil

leak

age
If

necessary
replace

Cooling
System

TEM
COUPLlNG

Non
Califomia

model

equipped
with
air

conditioning

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
Tem

coupling
however
is

properly
changed

with
the

cooling
requirement

ON
denotes
that

cooling
is

required
and
the
fan

operates
up
to

about
2

900rpm
When

high
cooling
is

not

required
during
cold
season
with

the

engine
warmed

up
etc
the

oper

ation

is

placed
under
OFF
condition

and
the
fan

slips
at
about
2

050

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
silicone

oil
is
forwarded

to
the

groove
that

transmits

torque
and
the

system
is

placed
under
ON

con

dition

When

the
valve
closes
silicone
oil
is

not

supplied
to
the

groove
oil
in

the

groove
is
accumulated

on
the
Tem

coupling
periphery
due
to
the
centrifu
1
Bi
metal

thermostat

2

Slide
valve

3

Reserve
chamber

fOl
OFF

4

Bearing

5

Coupling
part
labyrinth

6
Driven

part

C0130

Fig
CO
5

Tem

coupling

gal
force
and
led
into

the
reserve

chamber
Now
oil
is
eliminated
from

the

groove
and
the

system
is

placed

under
OFF
condition

With
this

system
when
fan

cooling

is

not

required
the

output
loss

IS

miniinized
and
noise
can
be
far

reduced

Q

i
tionalCOUPling

WATER
PUMP

SPEED

Q

ON

OFF

Tem
coupling

WATER
PUMP

SPEED

C0029

Fig
CO

6
Characteristic

of

Tern

coupling

I

SPECTION

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

CO
4
THERMOSTAT

REMOVAL
AND

INSTALLATION

I
Drain

cool
nt

partiaUy

2

Disconnect

upper
radiator

hose
at

water

outlet

3

Disconnect
air

hose
for

air

injec

tion

systein
at
check
valve

Fxcept

FU

models

4

Loosen
belt

for
air

injechon

system
by
loosening
idler

pulley
se

curing
nut

and

adjusting
bolt

Except

FU
models

CD
@
ID

I

2

3
C0053

Idler

pulley

Nut

Water
outlet

Fig
CO
7

Disconnecting
Air
Hose
and

Loosening
Belt

Except
FU
models

5
Loosen
bolts
and
remove
idler

pulley
bracket

Except
FU
models

6
Disconnect
air

induction

pipe

FU
models

7
Remove

bolts
and
remove
water

outlet

gasket
and
thermostat
from

thermostat

housing

I

Thermostat

2
Air
check
valve

Except
FU
models

3
Water
outlet

Fig
CO

Removing
Thennostat

8

After

checking
thermostat
rein

stall
with
a
new

housing
gasket
in

place

9
Reinstall
water
outlet

10

Replenish
coolant
and

check
for

leaks

INSPECTION

I

Submerge
thermostat
in

hot

water
SOC
90F
above
the

specified

temperature
Refer
to
Service
Data

and

Specifications

2

After

preparing
for
the
marked

screwdriver

at
about
8

mm
0
31
in

from
the

tip
inspect
the
lift

height

H
of
valve

by

inserting
it

f

C0097

Fig
CO
g
In

pecting
Thermostat

3
Now

place
thermostat
in

water

SoC
90F
below
the

specified
temper

ature

If
thermostat
does
not

operate
at

the
above

specified
temperature
it

must
be

replaced
because
it
cannot
be

repaired

Note

If

necessary
check
a
new
ther

mostat
before

installing
it
in

the

engine

RADIATOR

The
radiator
filler

cap
is

designed
to

maintain
a

pre
set

pressure
0
9

kgfcm2

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

wn
valve
allows
air
to

re
enter
the

radiator

preventing
the
formation
ofa

vacuum
in
the

cooling
system

On
models

equipped
wi

th
the
au
to

malic

transmission
the
oil
cooler
is
Cooling
System

combined
with
the
radiator
to

cool

transmission

fluid

REMOVAL
AND

INSTALLATION

1
Drain

coolant
into
a

clean
con

tainer

2
Disconnect
radiator

upper
and

lower
hoses

On
models
with
automat

ic

transmission
disconnect
cooler
inlet

and
ou
tlet
lines

from
radiator

3
Rem
Ne
fan
shroud

retaining

bolts
and
remove
fan
shroud

4
Remove
radiator

retaining
bolts

and
then

remove
radiator

upward

S
I

nstaD
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

direction

when
hoses
are
assembled

3
Ensure
that
clearance
between

radiator
hose
and

any

adjacent
parts
is

30
mm
1
18
in
min
On
air
condi

tioner

equipped
models
a
minimum

clearance
of
18
mm
0
71
in
should

exist
between

compressor
and
hose

4

Ensure
that

clearance
be
tween

shroud
and
fan
is

even
at
any
place

Note
Be
careful
not
to

damage
radi

ator
fins
and
core
tube
when
install

ing

INSPECTION

Radiator

cap
should
be
checked
for

working
pressure
at

regular
tune

up

intelVals
First
check
rubber
seal
on

cap
for
tears
cracks
or
deteriontion

after

cleaning
it
Then
ins
taD
radiator

cap
on
a

tester
If

cap
does
not
hold

or

will

not
release
at
the

specified
pres

sure

replace
cap

Fig
CO
lO

Testing
Radiator

Cap

CO
5
Also

inspect
radiator
for

leakage

using
cap
tester
and

applying
a

pres

sure
of
1

6

kgfcm2
23

psi

If

a

leakage
is
detected

repair
or

replace
radiator

ET116

Fig
CO
II

Testing
Cooling
System

Prtuurt

RADIATOR

RESERVOIR
TANK

OPERATION

The
radiator
reservoir
tank
is

mounted
to
the

right
hand
side
core

support
through
the
bracket
When

the

coolant

temperature
in
the
radiator

rises

and

pressure
builds

up
to
an

extent
the

pressure
relief
valve

provided
in

the
radiator

cap

opens
to

release
excess
coolant
into

the
re

servoir

tank
When
the
coolant

temper

ature
lowers
and

pressure
decreases
in

the
radiator
the
vacuum
valve

provid

ed

in
the
radiator

cap
opens
to
allow

the
coolant
to

re
enter
the
radiator

Condition

Loss
of

water

Poor
circulation

Corrosion

Overheating

Over

cooling
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

Inoperative
torque
coupling
or

tem

coupling

Loose
fan
belt

Restricted
radiator

Inaccurate

temperature
gauge

Impurity
in
water

Inoperative
thermostat

Inaccurate

temperature
gauge

CO
7
Corrective
action

Repair

Repair

Tighten

Tighten

Replace

Check

engine
oil
for

contamination
and
reml

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
flush

ed

thoroughly
at
least
twice
a

year

Permanent
antifreeze

Ethylene
glycol
base

can
be

used

throughout
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

Replace

Adjust

Flush

radiator

Replace

Use
soft
dean
water

Replace

Replace

TEMPERATURE
SENSOR

Removal

I

Using
pliers
flatten

clip
con

necting
vacuum

hose
to

sensor
vacuum

tube

1

Pipe

2
Catch

3
Fixed
with

adhesive

4
Hose

5
Tab

6

Clip

7
Gasket

EC019

Fig
EF
7

Removing
Seruor

2
Disconnect
hose
from

sensor

3
Take
off

clip
from
sensor
vacuum

tube
and
dismount
sensor

body
from

air
cleaner

Note

The

gasket
between

sensor
and

air

cleaner
is
bonded
to

the
air

cleaner

side
and

should
not

be

removed

Installation

Mount
sensor
on
the

specified

position

2

Insert

clip
into

vacuum
tube
of

sensor
After

installing
each
vacuum

hose

secure
hose
with
the

clip

Note
Be

sure
to
install
vacUl
11n

hose

correctly
Correct

position
is
R
H

side
to

Ntisan

mark
at
the

top

face
of
sensor
for
intake
manifold

L

H
side
for

Deuum
motor

VACUUM

MOTOR

1

Remove

screws

securing
vacuum

motor

to
air
cleaner

2

Disconnect

valve
shaft

attached

to

vacuum
motor

diaphragm
from
air

control
valve

and

remove

vacuum

motor

assembly
from
air

cleaner

3
To
install

reverse
the

removal

procedures
Engine
Fuel

Fig
EF

8
Removing
Vacuum
Motor

INSPECTION

AIR

CLEANER
FILTER

Viscous

paper

type
air

cleaner
filter

does

o
ot

rt

quire
any
cleaning
opera

tion

until
it

is

replaced
periodically

Brushing
or

blasting
operation
will

cause

clogging
and
result

in
enrich

ment

of
carburetor
mixture

and

should
never
be

conducted
For
reo

placement
interval
of
air

cleaner
filter

refer
to

Maintenance

Schedule

AUTOMATIC

TEMPERATURE

CONTROL
SYSTEM

Engine
failures

resulting
from
a

malfunctioning
A
T
C

system
are

manifest

during
cold
weather

opera

tion
Such
failures

include

Engine
stall
or
hesitation

Increase
in
fuel

consumption

Lack
of

power

If
these

phenomena
should

occur

check

A
T
e

system
as

described
in

the

following
before

carrying
out

inspection
of

carburetor

I
Check
that

vacuum
hoses
are

se

l

urely
connected
in
correct

position

2

Check
each
hose

for
cracks
or

distortion

3

Check
A
T

C

system
for

proper

function
as

follo
ys
Confirm
that

engine
is

cold
before

starting
test

With

engine
topped
disconnect

fresh
air

duct
if
so

equipped

Place
a
mirror
at
the
end

of
air

cleaner
inlet

pipe
as
shown
and

check

to
see
if
air
control
valve

is
in
correct

position

EF
4
Fig
EF
9

Inspecting
Valve
Po

man

Air
control
valve
is

in
correct

posi

tion
if
its
cold
air
inlet

is

open
and

hot

air
inlet
is

closed

4
Start

engine
and

keep
idling

Immediately
after

engine

starting

check
air
control

valve
for

correct

position
as
described
above
In

this

case
correct

position
of
air
control

valve
is

the

reverse
of

step
3

under

hood
air
inlet
is
closed

and
hot
air

inlet
is

open

S

Check
that
air
control
valve

grad

ually
opens
to

cold
air

inlet
side

as

engine
warms

up
When

environmental

temperature
around

temperature
sen

sor
is
low

spend
more
time

for

engine

warming
up
operation
to
facilitate

smooth

operation
of
air
control

valve

If
the
above

test
reveals

any
prob

lem
in
the

opera
ion
of
air
control

valve

carry
out
the

following
test

VACUUM
MOTOR

I
With

engine
stopped
confirm

that

cold
air
inlet
is

open
and

hot
air

inlet
is

c1
Sed

If
not

check
air
control
valve
link

age
for

proper
operation

2

DiscoJln
ct
ac
um

motor
inlet

vacuum
hose

and
connect

another

hose
to
the

inlet
to

apply
vacuum
to

vacuum
motor

Vacuum
can

be

appli
d

by
breathing
in

tile
hos
e
end

as

shown
Then

confirm
that

the
air

control
valve

moves

3
With
hot
air
inlet
in

open
posi

tion
as

described
in

step
2

above

pinch
vacuum
hose
with

fingers
and

cut
off
air
from

vacuum
hose
In

this

condition

check
that
air
control

valve

maintains
the

condition
described
in

step
2

for
more
than

30
seconds

and

that
hot

air
inlet

is

open
If

diaphragm

spring
actuates

the
air
control
valve

by