1953 JEEP CJ heater

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

COOLING
SYSTEM

Contents

SUBJECT
PAR.

GENERAL
.G-l Antifreeze Solutions. .G-l6
Cylinder
Block.
..................
.G-8

Draining
Cooling System............... G-3

Engine
Overheating..
.................
.G-19
Fan
Belt.
......... .........
.G-18
Filling
Cooling System.................
G-2

Inhibited
Coolant Solution .G-l7

Temperature
Sending Unit.
...........
.G-l0

Thermostat
.........................
G-9

RADIATOR
.G-5
Radiator
and Heater Hoses.............
G-7
SUBJECT
PAR.

Radiator
Pressure
Cap.................
G-4

Radiator
Removal and Replacement..... G-6

WATER
PUMP.
. . .G-ll
Water
Pump Disassembly. .............G-13

Water
Pump Inspection.
..............
.G-12

Water
Pump Reassembly.
.............
.G-14

Water
Pump Removal and Replacement. .G-l5

SERVICE
DIAGNOSIS.
.G-20

SPECIFICATIONS
. .G-21

ANTIFREEZE
CHART.
..... ... .G-22

G-l. GENERAL
a.
The satisfactory performance of the Hurricane

F4
engine
is controlled to a great
extent
by the proper operation of the cooling system. The
engine

block is full length water jacketed which prevents
distortion of the cylinder walls. Directed cooling
and
large water holes, properly placed in the cylin­
der head gasket cause more water to flow past the
valve
seats
(which are the
hottest
parts of the

block)
and
carry
the heat away from the valves, giving positive cooling of valves and seats.

Minimum
temperature of the coolant is controlled by a thermostat mounted in the
outlet
passage of
the engine. When the coolant temperature is below
thermostat-rated temperature, the thermostat re­ mains closed and the coolant is directed through
the radiator-bypass
hose
to the water pump. When the thermostat opens, coolant flow is directed to
the top of the radiator. The radiator dissipates the
excess
engine
heat before the coolant is recirculated
through the engine.
The
cooling system is pressurized. Operating pres­
sure
is regulated by the rating of the radiator cap

which
contains a relief valve, b. The Dauntless V-6
engine
efficiency and per­formance is controlled to a great
extent
by proper
operation of the cooling system. The cooling system

does
more than cool the engine. It also directs
the flow of coolant to provide the
best
operating
temperature range for each part of the engine.

In
the Dauntless V-6
engine
coolant is forced by
the water pump into two main passages that run the length of the block on each side (Fig. G-l).
FIG.
G-1—COOLANT
FLOW
THROUGH
THE
DAUNTLESS
V-6
ENGINE

161

COOLING
SYSTEM

14263

FIG.
G-2—COOLING SYSTEM
COMPONENTS
V-6
ENGINE

1—
Radiator
Pressure Cap

2—
Hose
Clamp

3—
Radiator
Hose (Inlet-Upper)
4—
Radiator
Hose (Outlet-Lower) 5—
Bolt
6—
Water
Pump Assembly 7—
Cap
8—Thermostat
By-Pass Hose
g—Water Outlet
Elbow

10—
Gasket

11—
Thermostat
12—
Water
Pump Gasket

13—
Dowel
Pin
14—
Radiator
Shroud (Heavy Duty Cooling) 15—
Pulley

16—
Fan
Spacer
17—
Fan
and Alternator Belt

18—Fan

19—
Lockwasher

20—
Radiator

21—
Drain
Cock
From
these
main passages, the coolant flows around
the
full
length of each combustion chamber.

After
cooling the block, the coolant passes through
ports between the block and each cylinder head.
These
ports direct most of the coolant flow around the exhaust valve area to prevent hot exhaust
gases

from
overheating the exhaust ports.

From
the cylinder heads, the water passes into a
water
manifold between each of the heads and the

water
pump. If the thermostat is closed, the coolant
is ported back to the pump where it is recirculated

back
into the pump and into the engine. After the
coolant heats enough to open the thermostat, the coolant is directed from the water manifold through
a
hose
to the top of the radiator and then through
the radiator which acts as a heat exchanger to cool the fluid. The coolant is then ported through a
hose

from
the bottom of the radiator to the pump, which

recirculates
it back to the engine.

The
cooling system is pressurized. Operating pres­
sure
is regulated by a relief valve in the radiator

cap. The
heater inlet
hose
is connected to a port on
the right bank cylinder head. The outlet
hose
is connected to the heater adapter tube on the water

pump.

c.
It is recommended when using water for coolant
that the cooling system be flushed and checked for leaks twice a year, preferably in the
fall
before
antifreeze is added and in the spring when the antifreeze is drained.

Reverse
flushing
will
aid greatly in removing rust 162

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

G and
scale, especially when used with a flushing
solution. A cleaning solution should be used to

loosen
the rust and scale before reverse flushing
the cooling system.

Flushing
is accomplished through the system in a direction
opposite
to the normal coolant flow.
This

action causes the water to get behind the corrosion

deposits
and force them out. To do this, remove
the upper and lower radiator
hoses.
Then
attach a
drain
hose
at the top of the radiator. Attach a new
piece of
hose
to the radiator
outlet
at the
bottom
and
insert the flushing gun. Connect the water
hose

to the flushing gun to a water
outlet
and the air
hose
to an air line.
Turn
on the water and when
the radiator is
full,
apply the air in short blasts,
allowing the radiator to
fill
between
blasts.
Con­
tinue this flushing operation until the water runs

clear
through the top
hose.

With
the thermostat removed, attach a leadaway
hose
to the water
hose
inlet. Also attach a length
of new
hose
to the water
outlet
connection at the
top of the engine.
Turn
the water on and
fill
the
water jacket and then apply air in short blasts.
Continue
this flushing until the water runs clear.

Also
do the hot water heater. Remove heater water

outlet
hose
from heater core. Remove inlet from 163

G
COOLING SYSTEM
engine
connections. Insert flushing gun and flush
heater core.
Care
must be taken when applying air
pressure to prevent damage to the heater core.

G-2.
Filling
Cooling System
To
fill
the cooling system, remove the
fill
cap and

fill
the tank to the top. Replace the cap and run
the
engine
at medium speed for approximately one
minute. Remove the cap and recheck the coolant level. Add more coolant if necessary to bring the level back to the top of the tank. If the cooling system is filled when the
engine
is cold, recheck the coolant level after the
engine
has warmed up.
This

will
ensure that the thermostat has opened allow­ ing complete cooling system circulation.

Always
correct any cooling system leaks before installing antifreeze. A corrosion inhibitor should be used in the cooling system to prevent the forma­
tion of rust and scale. A quality brand antifreeze containing a corrosion inhibitor should be used.

When
the antifreeze is drained in the spring, a
corrosion inhibitor should be added with the water.

Note:
Cooling system components for both V6 and

F4
engines
are shown in
Figs.
G-2 and G-3.

G-3. Draining
Cooling System

To
completely
drain
the cooling system, open the

drain
in the
bottom
of the radiator and also a

drain
on the right side of the cylinder block on the
Hurricane
F4 engine. The Dauntless V-6
engine

has two
drain
plugs, one located on each side of the cylinder block. Both plugs must be removed to
completely
drain
the cooling system.
Remove the radiator cap to break any vacuum
that may have developed.

Should
the cooling solution be lost from the system

and
the
engine
become
overheated do not
refill

the system immediately but allow the
engine
to cool or
refill
slowly while the
engine
is running. If
cold solution is poured into the radiator while the

engine
is overheated there is danger of cracking the

cylinder
block and/or cylinder head.
G-4.
Radiator Pressure
Cap

All
radiators are equipped with pressure caps which
reduce evaporation of cooling solution and make the
engines
more efficient by permitting slightly
higher operating temperatures. When operating
properly,
the pressure cap permits pressure build-up

in
the cooling system during periods of severe heat

load.
This
pressure increases the boiling point of the coolant and thus reduces overflow losses. The

effectiveness
of the cap is limited by its opening
pressure and the boiling point of the coolant (see
note
below). The pressure cap employs a spring-
loaded, rubber-faced pressure seal which presses against a seat in the radiator top tank. Spring pres­

sure
determines the opening pressure of the valve.

A
typical pressure cap is shown in Fig. G-5.

Note:
Refer to cooling system specifications (Par.

G-21)
for opening (relief) pressure when the ve­
hicle is equipped with either the
Hurricane
F4
or
Dauntless V-6 engine. If a new cap is required, always install a cap of the same type and pressure
rating
specified. It should never be altered or re­
placed by a plain cap.

A
vacuum release valve (Fig. G-5) is employed to
prevent undesirable vacuum build-up when the system
cools
down. The vacuum release valve is
held against its seat under light spring pressure.

Vacuum
in the system is relieved by the valve
which
opens
at V2 to 1 psi. [0,035 a 0,07 kg-cm2]

vacuum.
A pressure tester can be used to check and
test
the vacuum pressure rate (see Fig. G-6).
Although the mechanism of the pressure cap re­ quires no maintenance, the cap should be inspected
periodically for cleanliness and freedom of opera­ tion. The pressure cap gasket and radiator filler neck seat should also be inspected to be sure they

are
providing a proper seal. If the rubber face of
the valve is defective, a new cap should be installed.
Filler
neck reseating
tools
are commercially
avail­
able to correct minor
defects
at the surface of the seat. Follow instructions of the reseating tool manu­

facturer.

To
remove the radiator pressure cap when the
engine
coolant temperature is high or boiling, place

a
cloth over the pressure cap and
turn
counter­ clockwise about Vi
turn
until the first (pressure release)
stop
is reached. Keep the cap in this posi­
tion until all pressure is released.
Then
push cap
down and
turn
still
further until cap can be re­ moved. To install the pressure cap, place it in posi­
tion and
turn
it clockwise as far as it
will
go.

Caution:
Use extreme care in removing the radiator
pressure cap. In overheated systems, the sudden release of pressure can cause a steam flash and this

flash,
or the
loosened
cap can cause serious personal

injury.

G-5.
RADIATOR

Maintenance of the radiator consists of keeping
the exterior of the radiator core clean, the interior free from rust and scale, and the radiator free from

leaks.
Check
the cooling system fluid level and for
leaks each
2000
miles
[3.200
km.] or every 30
days, whichever occurs first.
This
exterior of the

radiator
core should be cleaned and the radiator inspected for leaks each
6000
miles
[9.600
km.]
of normal service of the vehicle. Cleaning should be performed by blowing out with air stream or water stream directed from the
rear
of the radiator.

Visual
inspection is not sufficient as the accumula­ tion of small particles of foreign material on core
surfaces can restrict cooling without closing the core openings.

Radiator
leakage occasionally results from cor­
rosion perforation of the metal but most leakage results from mechanical failure of soldered joints
when too much strain has been put on the joint.
Fractures
occur most
often
at the joint where the
radiator
inlet and
outlet
pipes are attached to the

tanks.
When the seams break, the entire soldered

joint
is
exposed
and can corrode, but breakage
rather
than corrosion is the
primary
cause of seam
leakage. Examine the radiator carefully for leaks before and after cleaning. Cleaning may uncover points of leakage already existing but plugged with
rust.
White, rusty, or colored leakage stains indicate 164

'Jeep*
UNIVERSAL SERIES SERVICE
MANUAL

G

FIG.
G-4—PRESSURE TESTING COOLING SYSTEM
1—Pressure Tester C-3499 previous radiator leakage. These
spots
may not be
damp if water only or methyl-alcohol-base anti­ freeze is in the cooling system since such coolants
evaporate readily. An ethylene-glycol-base anti­ freeze shows up existing leaks as it
does
not evapo­
rate.
The radiator may be tested for leaks by using

a
Pressure Tester Tool C-4080, as shown in Fig.

G-2.

When
the pressure cap opens, the sudden surge of

vapor
or liquid must blow out through the overflow
pipe. If the overflow pipe is dented or clogged,
the pressure caused by obstruction may cause dam­
age to the radiator or
hose
connections in the cool-
1
FIG.
G-5—RADIATOR PRESSURE
CAP
1—
Pressure
Cap

2—
Overflow
Tube

3—
Pressure
Seal 4—
Vacuum
Release Valve
5—
Radiator
Neck
FIG.
G-6—TESTING RADIATOR PRESSURE
CAP
1—
Radiator
Pressure Cap

2—
Adapter

3—
Pressure
Tester C-3499 ing system. To remove clogging material, run a
flexible wire through the overflow pipe.
G-6.
Radiator Removal
and
Replacement
a.
Drain
the radiator by opening the
drain
cock

and
removing the radiator pressure cap.

b.
Remove the upper and lower
hose
clamps and

hoses
at the radiator.

c.
Remove the four cap screws, lock washers and
flat washers that secure the radiator to the radiator
body support. Remove the radiator.

d.
To replace the radiator, reverse the removal

procedure.

G-7.
Radiator
Hoses
and
Heater Hoses

Air,
heat, and water deteriorate radiator and heater

hoses
in two ways: by hardening or cracking which
destroys flexibility and causes leaks; by softening
and
swelling which produces lining failure and
hose

rupture
and clogging. Examine
hoses
spring and

fall
for possible need of replacement or tightening.

If
hoses
are collapsed, cracked, or indicate a
soft

condition on the inside they should be replaced.
Correct
installation of a new heater
hose
is impor­
tant to prevent contact between the
hose
and the
exhaust manifold. On the
Hurricane
F4 engine the
molded curved end of the
hose
connects to the
hot water intake of the heater; the flexible end to the hot water valve on top of the cylinder head.
On
the Dauntless V-6 engine the heater inlet
hose

is connected to the
rear
of the intake manifold 165

G
COOLING SYSTEM G-20.
SERVICE DIAGNOSIS

SYMPTOMS
PROBABLE REMEDY

Overheating:
Lack
of Coolant Refill radiator
Thermostat inoperative . Replace thermostat
Water
pump inoperative. Overhaul or replace
Incorrect
ignition or valve timing. Set
engine
timing
Excessive piston blowby Check pistons, rings and cylinder walls
Fan
belt
broken or badly worn Replace
belt

Radiator
clogged
Reverse flush and clean
Air
passages
in core
clogged
Clean with water and air pressure
Excessive carbon formation. Remove carbon from cylinder head(s) Muffler
clogged
or
bent
exhaust
pipe
Replace damaged part

Loss
of Cooling
Liquid:
Loose
hose
connections
Tighten
connections

Damaged
hose
Replace
hose

Leaking
water pump Overhaul or replace

Leak
in radiator Remove and repair
Leaky
cylinder head
gasket
Replace
gasket
Crack
in cylinder block. Small crack can be closed with
Radiator
or Block Sealer

G-21. COOLING SYSTEM SPECIFICATIONS

Radiator
Cap:
Relief
Pressure

Vacuum
Valve Release.
Thermostat:
Rating

Starts to Open

Fully
Open

Water
Pump:
Type.

Drive

Radiator:

Type

Cooling System Capacity: Without Heater

With
Heater..

Fan:
Number of Blades Diameter

Drive
Belt: Angle of V

Length
Width
HURRICANE
F4
7 and 15 psi. [0,5 kg-cm2 and 1,05 kg cm2]
lA to 1 psi. [0,04 a 0,07 kg-cm2]

190°F.
[87,8°C]
180°F.
[82°C]

202°F.
[94°C]

Centrifugal
V-Belt

Tube
8s Fin
11 qt. [10,4 ltr.] 12 qt. [11,5 ltr.]
15" [38 cm.]
38°

42%" [108 cm.] [1,74 cmJ
DAUNTLESS
V-6 15 psi. [1,05 kg-cm2]
1 psi. [0,07 kg-cm2]

190°F.
[87,8°C]
180°F.
[82°C]

202°F.
[94°C]

Centrifugal
V-Belt

Tube
& Fin
9 qt. [8.5 ltr.]
10 qt. [9,4 ltr.]
4

\SbA"
[39,7 cm.]

38°

43.92"
[111,5
cm.] Vg"
[0.952
cm.] G-22. ANTIFREEZE CHERT

Quarts
i
Quarts
Ethylene Glycol

U.S.
Imperial
Liters
Fahr.
Cent.

10-Quart
System

2
m
2

16°
-
8.8°

3
2V2
2%
4°

-15.5°

4
3H
-12°

-24.4°

5 4M -34°

-36.6°

6
5

5Vs
-62°

-52.2°

11-Quart
System

2 2

18° -
7.6°

3 2H
2%
8°

-13.3°

4
3%
-
6°

:
-21.10

5 4M 4M -23°

-30.5°

6
5

SVs
-47°

-43.8°

12-Quart
System

2
1 m 2 1

19° ;
- 7.2°

3
2*A
10°
!
-12.2°

4
I
3H
3M 0°
;
-17.7°

5 !
4M 4^ :
-15°

s
-26.1°

6 1 5
5%
-34°

-36.6°
170

H

ELECTRICAL
SYSTEM
the condenser. Replace the condenser. If there is
no jump to full voltage, overhaul or replace the

distributor.

k.
With the points closed, connect the voltmeter

from
a clean, paint-free
post
on the distributor
body to the negative
post
of the battery. The volt­
age drop should be practically zero, a hardly
readable deflection on the voltmeter. If the volt­ meter registers a
voltage
drop, perform the checks

in
steps
1
and m following.

I.
Check
for
voltage
drop in the battery ground
cable.
Clean
the battery
post,
cable terminals, and contact surface on the bellhousing, or on body if

a
noticeable deflection of the voltmeter occurs,
m.
Check
for any
voltage
drop
between
the dis­

tributor
body and a clean, paint-free
spot
on the

cylinder
block. If there is any
voltage
drop, remove
the distributor and clean the mounting surfaces of
distributor
body and cylinder block.

H-5.
SECONDARY
CIRCUIT
If
satisfactory ignition is not obtainable with cor­

rect
point gap and tension; satisfactory condenser;
sufficient primary voltage; and correctly cleaned, gapped, and installed spark plugs; the secondary

circiut
should be investigated.

a.
Test the coil.
Bring
the coil up to operating
temperature using the coil heat feature of a coil tester, if available. Refer to the coil tester manu­

facturer's
instructions for specific hook-ups for
performing the checks given in
steps
b, c, and d following.
b. Connect the positive lead of the tester to the
battery terminal of the coil primary winding.
Con­
nect the tester ground lead to the coil tower. Mea­

sure
the resistance of the secondary winding. If the
resistance is more than
20,000
ohms, a fault in the
secondary winding is indicated.
c.
Check
for a grounded secondary by touching the tester ground lead to the coil cover. If resistance
is not over
100,000
ohms, the secondary is grounded
to the cover.

d.
If the secondary winding is satisfactory, mea­
sure
the primary current draw in accordance with
the instructions of the
test
equipment manu­
facturer.

e.
Check
the secondary circuit for leakage. With the coil primary in the circuit with the breaker unit of the tester, connect a long, high-tension
test
lead
to the coil tower.
Check
the secondary circuit for
leakage by performing the checks given in
steps
f. g, h, and i following.

Note:
In the following
tests,
a slight sparking and
meter deflection
will
usually be
seen
just as contact
is made.
This
is caused by capacitance and
does
not
indicate defective insulation.
f.
Check
distributor cap. Remove the coil lead from the cap and touch the
test
lead to the center contact
inside the cap. If the meter reading drops when the contact is touched or if sparking is seen, a leakage
path is present
between
the center contact and one
of the plug towers.
This
leakage path
will
be in the

form
of a
crack
or carbon track in the cap. Discon­ nect the spark plug wires from the cap one at a
time and
test
each plug contact with the high-
voltage
lead and with all other plug wires con­
nected. Any sparking or meter drop indicates that

a
leakage path exists
between
that particular con­
tact and an adjacent one. Testing the adjacent contacts
will
determine which pair is at fault,
g-
Check
distributor rotor. Touch the
test
lead to
the spring contact in the center of the distributor
rotor.
Any leakage in the rotor insulation
between

the contact and the shaft
will
cause a drop in the meter reading and usually sparking
will
be seen.

h.
Check
spark plug wires. Disconnect the spark
plug wires from the plugs and
test
the plug terminal of each. The meter reading should not drop below
the open secondary value (value before making contact). If it
does
or if a large spark occurs when
the
test
lead and the plug wire are separated, there
is a break in the insulation on that wire.

i.
Check
the coil tower insulation. Remove the
high-tension
test
lead from the coil tower and touch
the ground lead of the coil tester to several points

around
the base of the tower. Any sparking or deflection of the meter indicates a leakage path in
the tower insulation.

H-6.
Alternator Charging System

All
Jeep
Universal
Series vehicles have, as standard
equipment a 35-amp., 12-volt, negative ground
alternator and a transistorized
voltage
regulator.
For
repairing the alternator, many of its major components are furnished as complete assemblies

including:
complete brush assembly which requires no soldering or unsoldering of leads; two complete
rectifying
diode
assemblies which eliminate the need for removing and replacing individual diodes;

a
complete isolation
diode
assembly; and a rotor assembly complete with shaft,
pole
pieces, field coil,

and
slip rings.

The
transistorized
voltage
regulator is an electronic
switching device. It
senses
the
voltage
appearing at the auxiliary terminal of the alternator and
supplies the necessary field current for maintaining the system
voltage
at the output
terminal.
The out­
put current is determined by the battery electrical

load;
such as headlights, heater, etc.
The
transistorized
voltage
regulator is a sealed unit,
has no adjustments, and must be replaced as a
complete unit.

H-7.
Starting System

The
operation of the starter motor is controlled by
the ignition switch. The starter is made up of a
frame,
field coil, armature, and brushes.

The
starter solenoid electrically
closes
the circuit

between
the battery and the starter motor. When the ignition key is turned to its extreme right, the
solenoid is energized and
closes
the battery-to- starter-motor circuit.

Note:
All Jeep Universal Series vehicles have the

starter
solenoid switch secured to the starter motor
assembly. The Hurricane F4 and Dauntless V-6

engine
Prestolite starter drive is of the inertia type
(rexr
continued on
page
176) 174

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

H

12968
FIG.
H-4—WIRING
DIAGRAM—MODELS
CJ-5, CJ-6, DJ-5, DJ-6
LATE
F4
ENGINE

1—
Left
Headlamp
2—
Left
Parking and Signal Lamp
3— Right Parking and Signal Lamp 4— Right Headlamp
5— Generator
6— Ignition Distributor
7—
Oil
Pressure Sending Unit
8— Junction Block
9—
Horn

10— Foot Dimmer Switch 11—
Stop
Light Switch — Front
12— Temperature Sending Unit
13— Ignition
Coil

14— Starting Motor 15— Battery Ground Cable
16— Battery
17— Voltage Regulator 18—
Fuse

19— Instrument Cluster

A—Hi-Beam
Indicator

B—Auxiliary
C—Instrument
Lights

D—Oil
Pressure Indicator
E—Charging
Indicator
F—Temperature
Indicator

G—Fuel
Gauge
H—Instrument Voltage Regulator
20— Ignition and Starter Switch 21—
Flashei
(Directional Signal)
22—
Horn
Button 23— Directional Signal Switch
24— 4-Way Flasher Switch
25—
Flasher
(4-Way)
26—
Fuse

27—
Main
Light Switch 28—
Stop
Light Switch — Rear
29—
Fuel
Gauge
Tank
Unit
30—
Back-Up
Light Switch
31— Right
Tail
and
Stop
Lamp
32— Right Back-Up Lamp
33—
Left
Back-Up Lamp
34—
Left
Tail
and
Stop
Lamp

in
which the key can be removed. Turning the key
to the
left
energizes
auxiliary
equipment
such as
windshield wipers, radio, and heater. The turn
signal
lights
will
operate
with the
ignition
key in
either the
left
or right
position.
The
ignition
switch is held in
position
by a
tension
spring on the back
of the instrument panel and a
notched
bezel on
the front of the instrument panel.
H-8.
Lighting System

The
wiring for the lighting
system
is shown in the
wiring diagrams, Figs. H-2 thru H-7 of the manual,
which indicate the various units in relation to their

position
in the vehicle. The lighting circuit is pro­
tected
by an overload circuit breaker
mounted
on the rear of the light switch.
The
main light switch controls the lighting
system
177