1977 DATSUN PICK-UP check engine

Air
Conditioning

b

When

charging
hquefied
refrigerant

into
the

system
lith
the
can
turned

upside
down
to
reduce

charging

time

charge
it

only
through
high

pressure
valve
but
not

through
low

pressure
3
h
e

After

completion
of

charging
the

compressor
should

always
be

turn

ed
Several
times

manually
See

Figure
AC
22

t

UL
Q

v1ifl
j

AC739

Fig
A
C
22

ClUJrging
refrigerant
First

step

4
If

refrigerant
charging

speed
slows

down

charge
it
while

Iunning
the

compressor
for
ease
of

charging
After

having
taken
the

steps
up
to

3
above

proceed
with

charging
in

the

following

order

I
Shut
off

high

pressure
valve
of

manifold

gauge
back
into

refrigerant
can
and
can

may
explode

2

Run
the

engine
at

idling
speeds

about
1
500

rpm

3
Set
the

temperature
control

lever
and
fan
switch

at
maximum

cool

and
maximum

speed
respectively

4

Charge
refrigerant
while
con

trolling
low

pressure
gauge
reading
at

2
8

kgfcm2
40

psi
or
less

by
turning

in
or

out
low

pressure
valve
of
mani

fold

gauge
See

Figure
AC
23
Caution
Never

charge
refrigerant

through
high

pressure
side
of

sys

tem
since
this
will
force

refrigerant

t

AC740

Fig
A
C
23

Charging

refrigerant
Second

step

AC
14
5
When

refrigerant
can
is

empty

fully
close

both
Ives
of
manifold

gauge
and

replace
refrigerant
can
with

a

new
one

Before

opening
manifold

gauge

valve
to

charge
refrigerant
from
new

can

be
sure
to

purge
air
from
inside

charging
hose

6

Charge
the

specified
amount

of

refrigerant
into

system
by
weighing

charged
refrigerant
with
scale

Over

charging
will

cause

discharge

pressure

to

rise

AC255

Measure
the

amount
of

charged

refrigerant
with
a
scale

Make
a

note
of
the

amount

charged

from

can

Fig
AC

24
Measuring
refrigerant

Refrigerant
capacity

Unit

kg
lb

Refrigerant
Minimum

Maximum

R
12

0

7
1
5
0
9
2

0

Note
The

presence
of
bubbles
in

sight
glass
of

receiver

dryer
is
an

unsuitable
method
of

checking
the

amount

of

refrigerant
charged
in

system
The
state
of
the
bubbles
in

sight
glass
should

only
be
used
for

checking
whether
the
amount
of

charged
refrigerant
is
small
or
not

The
amount
of

charged
refrigerant

can
be

correctly

judged
by
means

of

discharge
pressure
Refer
to
Re

frigerant
Level
Check

3

Piping

Flared
section
of

high
pressure
and

low

pressure
flexible

hose

Pipe
connections

rvice

valve

4

Evaporator
housing

Jnlet
and

outlet

pipe
connections

Expansionvalve

ELECTRIC
LEAK
DETECTOR

for
the

operational
procedures

refer
to

the
instructions
furnished
with

each
electric
leak
detector

Amount

of

refrigerant
Air

Conditioning

REFRIGERANT

LEVEL
CHECK

SIGHT
GLASS

Sight
glass
is

provided
at
the

top
of

receiver

dryer
One

guide
for
whether

there
is

enough
refrigerant
in

system
is

given
by
observing

refrigerant
flow

through
sight
glass
However
this

method

is
unsuitable
for

judging
the

amount
of

refrigerant
The
correct

refrigerant
level

can
be

judged
by

measuring
t
e

system
pressures
in
ac

cordance
with
the

procedures
de

scribed
Performance
Test

I

Start
the

engine
and
hold

engine

speed
at
1
500

rpm

Almost
no

reftigerant

Check
item

Temperature
of

high
pressure

and
low

pressure
pipes
Almost
no
difference

between

high

pressure

and
low

pressure
side

temperature

Bubbles
flow
continu

ousty
Bubbles
will

disappeu
a
nd
some

thing
like
mist

will

now
when

rerrigeran

is

nearly
gone
State
insightglass

A

I
I

AC256

Pressure
of

system
High
pressure
side

is

abnormally
loW

Repa
ir
Stop

compressor
and

conduct
an
overall

check
Insufficient

High
pressure
side
is

warOl
and

low

pressure

side

is

fairly
cold

The
bubbles
are
seen

at
intervals
of
1
2

seconds

A

r

I

AC257

Both

pressures
on

high

and
low

preS
ure
sides

are

slightly
low

Check
for

gas
leakage

repair
as

required
re

plenish
and

charge

system

AC

16
2

Set

temperature
control
lever
to

maximum

position

3

Set
blower
to
maximum

speed

4

Check

sight
gla
after
the

lapse

of
about
five

minutes
Judge
according

to
the

following
table

AC741

Fig
AC
26

Temperature
control
lever

Suitable
Too
much

refri
crant

High
pressure
side
is

hot
and
low

pressure

side
is
cold
High

pressure
side
is

abnormally
hot

Almost

transparent

Bubbles

may
appear

when

engine

speed
is

raised
and
lowered
No
bubbles
can
be

seen

No
clear
difference
exists
between
these
two

conditions

M

II
I

AC258

Both

pressures
on

high

and
low

pressure
sides

are
normal
Both

pressures
on

high

and
low

pressure
sides

are

abnormally
high

Discharge
reft

gerant

from

service
valve
of

10
11

pressure
side

Notes

a
The
bubbles
seen

through
the

sight

glass
are
influenced

by
the
ambient

temperature
Since
the
bubbles
are

hard
to
show

up
in

comparatively

low

temperatures
below
200C
6S0

F
it
is

possible
that

a

slightly

larger
amount
of

refrigerant
would

be
filled
if

supplied
according
to

the

sight
glass
Be

sure
to
recheck

the
amount
when
it

exceeds
200C

680F
In

higher
temperature
the

bubbles
are

easy
to

show

up

b

When
the

screen
in
the

receiver

dryer
is

clogged
the
bubbles
will

appear
even
if
the
amount
of

refrig

erant
is
normal
In
this
case
the

outlet
side

pipe
of
the
receiver

dryer
becomes

considerably
cold

PERFORMANCE
TEST

Check
for
the
amount
of

refrigerant

in
the

system
can
be

made

by
meas

uring

pressure
on

discharge
side

The

correct
amount
of

refrigerant
is

in
the

system
if

pressure
on
the

discharge
side
is
within

the

specified

range
For
details
refer
to

Perform

ance

Test
described
later

Overcharging
will
show

up
in

higher

pressure
on
discharge
side

COMPRESSOR
OIL

LEVEL

CHECK

The
oil

used
to
lubricate

compres

sor
circulates
into

system
from
the

oil

sump
while

c9mpressor
is

operating

The

efore
to

correctly
measure
com

pressor
oil
the

amount
of
oil

flowing

to

system
must
be

considered
If
a

considerable
amount
of

leakage
of

refrigerant
gas
happens
the

leakage
of

compressor
oil
is
also
considered

There

will
be

no

compressor
oil
leak

age
from
a

completely
sealed

system

When

system
operates
under

satisfying

condition
the

compressor
oil
level

check
is

unnecessary

When

checking
the
level

of
com

pressor
oil
or

when

replacing
any

component
part
of
the

system
use
the

following
service

procedure
This

fa

cilitates
to
return
oil
to

compressor

I

Operate
compressor
at

engine

idling
speed
1
000

rpm
or

below

with
controls
set

for
maximum

cooling
Air

Conditionin
j

and

high
blower

speed
for
10
to

15

minutes
in

order
to
return

compressor

oil
to

compressor

2

Stop
the

engine
and

discharge

refrigerant
of

system
and
then

remove

compressor
from

the
vehicle

3
Remove

compressor
fIller

plug

Drain

compressor
oil
from

compres

sor
oil

sump
and

measure
the

amount

4

Compressor
oil
is

satisfactory
if

the

following
amount
of
oil

remains
in

the

compressor

Residual
oil

S5
to
128

gr
3
to
4
oz

5
Check
the
cleanliness
of
the
oil
If

the
oil
contains

chips
or

other

foreign

material
clean
oil

5ump
with
new

oil

6
Discard
the

used
oil
and

fili
with

the
same
amount
of
new
oil
Add

oil
if

found
less
than
above
amount

Fig
AC
27

Filler

plug

If

compressor
is

inoperative
due
to

faulty
compressor
or

heavy
loss
of

refrigerant
remove

compressor
and

repair
as

necessary
Then

pour
oil

up

to
correct
level
and
install
on

engine

After
above

steps
have
been

complet

ed
recheck
oil
level
drain
oil
to

correct
level
if

level
is

excessively
high

PERFORMANCE
TEST

The
cooling

performance
of
the
air

conditioner

changes
considerably
with

changes
in

surrounding
conditions

Testing
must
be

performed
using
the

correct
method
This

test
is
used
to

judge
whether

system
is

operating
cor

rectly
and

can
also
be
used

as
a

guide

in

checking
for

problems

I

Park
the
vehicle
indoors
or
in
the

shade

AC
17
2

Open
all
the
windows
of
the

vehicle
fully
However

close
the

doors

3

Open
the
hood

4

Connect
manifold

gauge
to

high

and
low
side
service
valves
of
the

system
Refer
to

Handling
Manifold

Ga

uge

5

Set
fan
control
lever
to
maxi

mum

6
Set

temperature
control
lever

to

max
cool

position

7
Start
the

engine
and
hold

engine

speed
at
1
500

rpm

S
After
the
air

conditioner
has
been

operated
for
about
10
minutes

measure

system

pressures
at

high
pres

sure

discharge
side
and
low

pressure

suction
side

9
Measure
the

temperature
of
dis

charge
air
at

outlet

grille

10
Measure
the

temperature
of

capin

11
Measure
ambient

temperature

and

humidity
one
meter
3
3
ft

away

from
condenser
front
Be

careful
not

to

expose
dry
buib

and
wet
bulb

to

direct

sunlight

12
Check
for

any
abnormalities

by

comparing
the
test

results
with
stand

ard

pressure
in
Performance

Chart

Notes

a
The

pressure
will

change
in
the

followi

g
manner
with

changes
in

conditions

When

blower

speed
is

low
dis

charge

pressure
will

drop

When
the
relative

humidity
of
in

take
air
is
low

discharge
pressure

will

drop

b

The

temperature
will

change
in
the

following
manner
with

changes
in

conditions

When
the
ambient
air

temperature

is

low
the
outlet
air

temperature

will
become
low

If
the
test
reveals
that
there
is

any

abnormality
in

system
pressure
isolate

the

cause
and

repair
by
reference
to

the
Trouble

Diagnoses
and
Cor

rections

Air

Conditioning

PERFORMANCE
TEST
DIAGNOSES

Condition

Discharge
air
too
warm

a
Both

discharge
and
suction

pres

sure
too

high

b
Both

discharge
and
suction

pres

sure
too
low

c
Discharge

pressure
too

high
and

suction

pressure
too
low

d
Suction

pressure
too

high
and

discharge

pressure
too
low

e

Discharge

pressure
normal
and

suction

pressure
too

high

t
Discharge

pressure
normal
and

luction

pressure
too
low

g
Suction

pressure
normal
and

discharge
pressure
too

high

h
Both

discharge
and
suction

pres

sure
normal

Air

conditioning
is

operating

properly

Discharge
air
normal

or
too
cold

a

Discharge
pressure
normal
and

suction

pressure
too
low
Probable
cause

Air

mixed
with
refrigerant
in

system

Overcharge
of

refrigerant

Loose
fan
belt
or

engine
over

heating

Obstructed
or

dirty
condenser
fins

Insufficient

refrigerant
charge

Over

filling
of

compressor
oil

Damaged
compressor
valve
or

pack

ing

Loose

compressor
drive
belt

Clutch

slippage

Faulty
expansion
valve

Clogged
expansion
valve
strainer

Water
has
frozen
at

expansion

valve

Faulty
expansion
valve

Faults
of
both

a
and
h
exist

Air
leaks
from

engine
com

partment

Restricted
air
flow

through
evapo

ratof

Slow
blower
motor

speed

AC
21
Corrective
action

Evacuate
and

charge
system

Discharge
some
of

refrigerant
to

correct
level

Adjust
fan
belt
or
check

cooling

system

Clean
exterior

surface
with
water

Add

refrigerant

Drain
oil
and
correct
oil
level

Refer

to

Compressor
oil
level

check

Repair
or

replace
compressor
Refer

to

Compressor

Adjust

Repair
Refer
to

Compressor

Reinstall

sensing
bulb
correctly
to

keep
it

tight
to

pipe

Replace

Clean
strainer

Evacuate
and

charge
system

Replace

Correct

sealing

Clean

evaporator
fins

Check
and

repair
blower
motor
and

wiring

Air

Conditioning

NOISE
DIAGNOSES

NOISY

I

I

I
Set
fan

switch
on

2

Change
the

engine
rpm

frequently

Detect

the
source
of

noise

I

From

engine
compartment
From
cabin

Cooling
unit

j

Check
the

resonant
sound
when
the

engine
rpm
is

changed

I

I

No

resonant
sound

Compressor
itself
makes
noise
j

Blower
motor

makes
noise

Replace
or

repair
blower

Resonant

sound

Repeat
compressor
clutch
ON
and

OFF

This

checking
can
be

performed
by
changing

engine
rpm
while

fan
switch
is

set
at

ON
Retighten
compressor
bracket
bolt

If

piping
is

resonating
add

clip

Noisy
only
when
clutch
is

engaged
Noisy
when

clutch
is
not

engaged

I

Check
drive
belt
for

slackness

Check
for
loose

compressor
mounting
bolts

I

I
Remove

compressor
belt
then
turn

compressor

pulley

by
hand
If
noise
is
heard

repair
com

pressor
clutch

If

OK

If
loose

Compressor
itself
makes
noise

Repair
or

replace
compressor
Retighten
or

adjust

Nl1

IDLER

PULLEY

FAN
BELT
TENSION

ADJUSTMENT

The

standard

compressor
drive

belt

tension
is
between

8
and
12

mm

AC480

Note
Be

sure
to

loosen

locking
nut

before

turning

adjusting
bolt
Re

tighten
it

after

adjustment

REMOVAL
AND

INSTALLATION

Remove
drive

belt

To
do
this
loosen

locking
nut

before

loosening

adjusting
bolt
Drive

belt
will
then
be
detached

2

Remove
idler

pulley
from
bracket

by
r

J1e

vM
or
king
nut

jiwT
9ff
t

llil
reverse
the

order
of

rerr
oval
jldJ
1
t

Jldr

J
I

INSPECTiON

Oheck
idler

pulley
for

smooth
rota

tion

G
0

llfHt
H
Y

d
H

u
t
1
W

n
l

ot
Jrk
H
l

Check
i

ler

pulley
bracket
for

cracks

Replace
arts
iffound

damaged

c

f
lOJ

gD
IlI
J
l

gtt
flvlnv

nOj
IH

q
g

cll
dE
m
J

COOLING
UNIT

REMOVAL
AND
oM1

INSTALl
A

1lIONI
gnillslUli
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C

19qm91
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6rn
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2

Disbhargiou
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iRefrflsll
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chargingrSystemiillidenGeneral
S

ervicel

sectiom5qiq
10
2
9
fl
1U
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oj
liD
Air

Conditioning

0
32
and
0
47
in

when

depressed

with
thumb

pressure
midway
between

the
crankshaft

and

compressor
pulleys

If

necessary
turn

adjusting
bolt

to

move
idler

pulley
up
or
down

until

belt

tension
is

correct

Idler

pulley

Crankshaft

pulley

AC456

Fig
AC
32

Adjustment
of
bolt
tension

3

Connect
low

and

high
pressure

pipes
to
their

proper
positions
in

engine
compartment

Notes

3
Be
sure

to
use
two

wrenches
when

connecting

pipe
joints

b

Plug
pipe

opening

immediately

after

pipe
disconnection

c
Be

careful
not
to

break

expansion

valve
This
valve
is

wrapped
with

heat

insulating
tape

0

J
JWu

J
1
2
ld

m

bm
Ufl

J51
8

I

1

lEldgJ
v
Jwm
j

y
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n
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C765

X

fIlO
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1551

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flip
1h
tqnPfffi2n
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i
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ip

j

at
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lsIliqr
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wlr
v
n

irWfiqX
ani

qiq

4q
v
Remo
e

tworgromll
ets
from

dash

panel
lots
n

5
lRemove

glovelbox
lBl
n1

oT
0

6

Detach

cooling
unit

cover

Icyom
n

AC

ZA
AC766

Fig
AC
34

Removing
cooling
unit

cover

7

Remove
three
ducts

from

cooling

unit

i

j

l

I

11

AC767

Fig
A
C
35

Removing
cooler
ducts

8
Remove
thermo

switch
control

cable
from

conne
ctor

9
Remove

cooling
unit

and
bracket

as
an

assembly

J

t

AC768

F

lIJAh
Cr
P

3
6
R
1

7
fi
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Ig

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f
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vehicle
bn

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with
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G

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a8f1l1

J
a

I
ld
1

51
b
nc

IOJni

QisconnecEf
twonleadliwif
eUcon
1

nectars
from

cooling
unitqiq
s
iuo
UHf

INSPECTION

Evaporator

Check

evaporator
for

leakage
or

damage
If

damaged
replace

Expansion
valve

Check

expansion
valve
for

leakage

or

clogging
If

clogged
clean
filter
in

expansion
valve
If

damaged

replace

RECEIVER
DRYER

AND

PIPING

REMOVAL
AND

INSTAUATION

Receiver
dryer

I
Disconnect

battery
ground
cable

2

Discharge
system
Refer
to

Dis

charging
System
under
General
Service

section

3

Disconnect

compressor
lead
wire

at

connector

4

Disconnect

cooling
pipes
at

joints

Acno

Fig
AC
39

Diaconnecting
coo

ing

pipes

Notes

a

Plug
all

piping

joints
immediately

after

pipe
disconnection
to

prevent

entry
of
dust
or
moisture
laden
air

into

receiver

dryer
or
air
aJOdi

tioning
system

b
Use

two
wrenches
when
dIsconnect

ing
cooling
pipes

5

Remove
four
screws

securing

receiver

dryer
bracket

to
vehicle

body

and
detach

compressor
relay
and

pres

sure
switch
as
an

assembly

6
To

install
receiver

dryer
and

piping
reverse
the
order
of
removal
Air

Conditioning

Notes

a

Apply
a
coat
of
fresh

compressor

oil
to

sealing
surfaces
when
con

necting
cooling

pipes

b
Use
two
wrenches
when

connecting

cooling
pipes

c

Evacuate

cooling
system
then
re

charge
with

refrigerant

Refer
to

Evacuating
and

Checking

System
under
General
Service

sec

tion

d
Check

refrigerant

leakage
if
neces

sary
repair

Refer
to

Evacuating
and

Charging

System
under

General
Service
See

tion

Condenser

Disconnect

battery

ground
cable

2

Discharge

system
Refer

to
Dis

charging
System
under
General

Service

section

3
Drain

engine
coolant

4

Remove
radiator

grille

5

Remove

radiator

shroud
and

radiator

On
automatic
transmission

models

disconnect
both

torque
converter
oil

hoses

Note

While

cooling
water
is
hot

take

precautions

against
scalding

6
Disconnect
two

pipes
from

con

denser
remove
two

screws

securing

condenser

Condenser

can
now
be

removed

AC485

Fig
AC

40

Removing
conden
er

Notes

a
Use

two
wrenches
when
disconnect

ing
pipe

joints

b

Plug
openings
immediately
after

disconnecting
pipes

7

To
install

reverse
the
order
of

removal

AC

29
Tightening
torque

Flare
nut
for

copper
tube

from

compressor

2
5
to
4
0

kg
m

i8
to
29
ft
Ib

Flare
nut

for

copper
tube

to
receiver

dryer

2
5

to
3
5

kg
m

i8
to
25
ft
lb

Notes

a
When

disconnecting
and

connecting

cooler

pipes
be
sure
to

use
two

wrenches

b

Apply
a
coat
of
fresh

compressor

oil
to

sealing
surfaces
when

con

necting
cooler

pipes

c

To

prevent

possibility
of

explosion

due
to

high

pressure
within

cooling

system
do

not
clean
condenser

with
steam

Always
use
cold
water

or

cold

compressed
air

d
Evacuate

cooling
system
then
re

charge
with

refrigerant

Refer
to

Evacuating
and

Charging

System
under
General

Service
sec

tion

e
Check

refrigerant
leakage
if
neces

sary
repair
Refer
to

Checking
for

Leaks
under
General
Service

sec

tion

INSPECTION

RecelYer

dryer

Check
for

refrigerant
leakage
or

damage

Check
for

proper
connection
of

two

lead
wires

running
to

pressure

switch

If

any
component

part
is
found

damaged
replace
receiver

dryer
and

pressure
switch
as

an

assembly

Condenser

I

Check

inlet
and
outlet

pipe
joints

and

sealing
surfaces
for

damage
Re

place
parts
if

damaged
or

leaky

2

Clogged
condenser
fins
or

air

pas

sages
may
reduce

cooling
efficiency
of

condenser
Clean
these

areas
with

dry

compressed
air

Piping

Check

piping
for

leakage
If

leakage

occurs
at
connections

retighten

connecting
nuts

Replace
if

leakage

persists

Inspection

Check

continuiry
in
fan
switch

circuit
with
a
test
lamp
or

an
ohm

meter

I

011
I
2
3

ICD

Tt

tt

AC772

Fig
AC
45
Fan
switch

RESISTOR
FOR
FAN
SWITCH

Removal
and
Installation

I

Disconnect
battery

ground
cable

2
Remove

glove
box

3
Remove

cooling
unit
Refer
to

Removal
and
Installation
under

Cooling
Unit

4

Disconnect
resistor
lead
wires
at

connector

@

O
sn
I
3n

CD
00
@

AC492

Fig
AC

46
Resistor

for
fan
switch
Air

Conditioning

5

Remove
resistor

assembly
from

upper
side
of

cooling
unit

Resistor
is

inserted
into

case

6
To
install

res
istor
for
fan
switch

reverse
the

order
of
removaL

Inspection

Test

continuity
between
resistor

and
fuse

THERMO
SWITCH

Removal
and
installation

1
Disconnect

battery

ground
cable

2

Remove

glove
box

3
Remove

duct
from

cooling
unit

4

Disconnect
thermo
switch
control

cable
and
lead
wires

5

Remove
thermo
switch

Note

Capillary
lube
is
fitted
into

groove
in
cooler
unit

6
To

install
thermo
switch
reverse

the

order
of
removal

I

I

AC773

Fig
AC
47

Removing
thermo
switch

AC

32
Inspection

I

Fully
move
thermo
swirch
lever

to
COLD

2

Test

continuity
between

ter

minals
with
a
test

tamp
or

an
ohm

meter

Continuity
should
exist

3

Dip
capillary
tube
end

into
ice

water
Test
continuity
between
ter

minals

Continuity
should
not
exist

4

Replace
if
switch
is

found
dam

aged

F
I
C
D
SOLENOID
VALVE

Removal
and
installation

I

Disconnect
battery
ground
cable

2
Disconnect
lead
wires
and
vacu

um

tube

3

Remove
two
screws
securing
sole

noid

valve
and
remove
solenoid
valve

AC77
4

Fig
AC

48
Removing
F
l
C
D

solenoid
valve

4
To
install
solenoid
valve
reverse

the
order
of
removal

Inspection

1
Test

continuity
in
solenoid
valve

circuit
with

a
test

lamp
or
an
ohm

meter

2
Turn
both
fan
switch
and
thermo

switch
on

3
Run

engine
at
idle
and
check
to

be
sure
that
vacuum
is

present
in
line

between
solenoid
valve
and

diaphragm