check engine DODGE TRUCK 1993 Service Owner's Guide

•

CLUTCH
6-17
CLUTCH PEDAL INSTALLATION

(1) Lubricate pedal shaft, pedal shaft bore and all
bushings with Mopar Multi Mileage grease. (2) Insert pedal pin into cylinder push rod. Then
position clutch pedal in support. (3) Slide pedal shaft through clutch pedal bore and
bushings. (4) Install bolt that retains pedal shaft in support.
(5) Secure push rod to pedal pin with wave washer,
flat washer and retaining ring.

FLYWHEEL SERVICE
Inspect the flywheel whenever the clutch disc,
cover and housing are removed for service. Check
condition of the flywheel face, hub, ring gear teeth,
and flywheel bolts. Minor scratches, burrs, or glazing on the flywheel
face can be scuff sanded with 180 grit emery cloth. However, the flywheel should be replaced if the disc
contact surface is severely scored, heat checked,
cracked, or obviously worn. Cleanup of minor flywheel scoring should be per­
formed with surface grinding equipment. Remove
only enough material to reduce scoring (approximate­
ly 0.001 - 0.003 in.). Heavy stock removal is not rec­
ommended. Replace the flywheel if scoring is severe
and deeper than 0.076 mm (0.003 in.). Excessive
stock removal can result in flywheel cracking or
warpage after installation; it can also weaken the flywheel and interfere with proper clutch release. Check flywheel runout if misalignment is sus­
pected. Runout should not exceed 0.08 mm (0.003
in.).
Measure runout at the outer edge of the fly­
wheel face with a dial indicator. Mount the dial in­
dicator on a stud installed in place of one of the
flywheel attaching bolts. Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may cock the flywheel causing excessive runout. Check condition of the flywheel hub and attaching

bolts.
Replace the flywheel if the hub exhibits cracks in the area of the attaching bolt holes. Install new attaching bolts whenever the flywheel
is replaced and use Mopar Lock N' Seal, or Loctite
242 on replacement bolt threads.
Recommended flywheel bolt torques are:
• 75 N»m (55 ft. lbs.) for gas engine flywheels
• 137 N*m (101 ft. lbs.) for diesel flywheels Inspect the teeth on the starter ring gear. If the
teeth are worn or damaged, the flywheel should
be replaced as an assembly. This is the recom­ mended and preferred method of repair.
In cases where a new flywheel is not readily avail­

able,
a replacement ring gear can be installed. How­
ever, the following precautions must be observed to
avoid damaging the flywheel and replacement gear.
(a) Mark position of the old gear for alignment
reference on the flywheel. Use a scriber for this
purpose.
(b) Wear protective goggles or approved safety
glasses. Also wear heat resistent gloves when han­
dling a heated ring gear. (c) Remove the old gear by cutting most of the
way through it (at one point) with an abrasive cut­ off wheel. Then complete removal with a cold chisel
or punch. (d) The ring gear is a shrink fit on the flywheel.
This means the gear must be expanded by heating in order to install it. The method of heating and expanding the gear is extremely important. Ev­
ery surface of the gear must be heated at the same
time to produce uniform expansion. An oven or
similar enclosed heating device must be used. Tem­
perature required for uniform expansion is 325-350° F.

CAUTION:
Never
use an
oxy/acetylene torch
to re­
move
the old
gear,
or to
heat
and
expand
a new

gear.
The
high temperature
of the
torch flame
will

cause
localized heating
and
damage
the
flywheel.
In

addition,
using
the
torch
to
heat
a
replacement gear

will
cause uneven heating
and
expansion.
The
torch
flame
will
also
anneal
the
gear
teeth
resulting
in
rapid wear
and
damage
after
installation.

(e) The heated gear must be installed evenly to
avoid misalignment or distortion. A shop press and
suitable press plates should be used to install the
gear if at all possible.
(f) Be sure to wear eye and hand protection.
Heat resistent gloves and safety goggles are needed
for personal safety. Also use metal tongs, vise
grips,
or similar tools to position the gear as neces­sary for installation.
(g) Allow the flywheel and ring gear to cool
down before installation. Set the assembly on a
workbench and let it cool in normal shop air.

CAUTION:
Do not
use water,
or
compressed
air to

cool
the
flywheel.
The
rapid cooling produced
by

water
or
compressed
air can
distort,
or
crack
the
gear
and
flywheel.

DIAGNOSIS

PRELIMINARY
CHECKS

ENGINE COOLING SYSTEM OVERHEATING Establish what driving conditions caused the com­
plaint. Abnormal loads on the cooling system such as
the following may be the cause:

1.
PROLONGED IDLE, VERY HIGH AMBI­
ENT TEMPERATURE, SLIGHT TAIL WIND AT
IDLE, SLOW TRAFFIC, TRAFFIC JAMS, HIGH SPEED OR STEEP GRADES.
Driving techniques that avoid overheating are:
• Idle with A/C off when temperature gauge is at
end of normal range. * Increasing engine speed for more air flow is recom­
mended.

2.
TRAILER TOWING: Consult Trailer Towing section of owners manual.
Do not exceed limits.

3.
AIR CONDITIONING; ADD-ON OR AFTER
MARKET: A maximum cooling package should have been or­
dered with vehicle if add-on or after market A/C is
SYMPTOM AND ACTION

SYMPTOM
installed. If not, maximum cooling system compo­
nents should be installed for model involved per
manufacturer's specifications.

4.
RECENT SERVICE OR ACCIDENT RE­
PAIR:
Determine if any recent service has been performed
on vehicle that may effect cooling system. This may

be:

• Engine adjustments (incorrect timing)
• Slipping engine accessory drive belt(s) • Brakes (possibly dragging)
• Changed parts. Incorrect water pump or pump ro­
tating in wrong direction due to belt not correctly
routed
• Reconditioned radiator or cooling system refilling (possibly under filled or air trapped in system).
If investigation reveals none of the above as a
cause for an engine overheating complaint, refer to
the following Symptom and Action chart:
PRELIMINARY FIRST) ACTION
Blinking Engine Temperature
Warning Light or High Gauge indication - Without Coolant Loss
Normal during temporary operation
with
heavy load, towing
a
trailer,
high
outdoor temperatures, and/or on
a
steep
Loss
grade.

Coolant Loss
Hot Vehicle (Not Engine) Heat Damage,
Hot Carpet, Seat,
Hot
Catalytic
Converter,
Smoke, Burnt Odor
Hot Engine Crackling Noise Hot Smell
Severe Local Hot Spots
Coolant Color
Coolant Reserve Bottle Level Changes
Coolant Not Returning To Radiator
Improper refilling procedures
can
result
in
trapped air
in
the
system.
Subsequent
operation
of the
pressure cap and coolant reserve system
will
deaereate
the

cooling
system.
A low
coolant
level
will
then result
in the
Coolant Reserve
Tank. Add coolant.
If
condition persists,
refer
to
System
Diagnosis.

Check
heat shielding, exhaust
system,
engine emission controls, ignition
timing, engine misfiring.

A
moderate amount
of
sound from heating
metal
can
be
expected
with
any

vehicle. However,
a
crackling sound from
trie
thermostat
housing,
a hot
smell and/or severe local
hot
spots on
an
engine can indicate blocked coolant

passages,
bad castina, core sand deposits and subsequent blockage,
cracked cylinder block
or
head,
or
blown cylinder head gasket. Usually
accompanied
with
coolant
loss.

Coolant
color is
not
necessarily
an
indication
of
adequate
temperature
or

corrosion
protection.
Level changes
are to be
expected as coolant volume fluctuates
with
engine
temperature.
If the
level
in the
bottle
is
between
the
Maximum and Minimum
marks
at
normal engine operating temperature,
the
level
should
return
to

within
that
range
after
operation
at
elevated temperatures.

Coolant
will
not
return
to the
radiator
if the
radiator cap vent valve does
not

function,
if
an
air
leak destroys vacuum,
or if the
overflow
passage
is
blocked
or
restricted. Inspect
all
portions
of the
overflow
passage,
pressure

cap,
filler
neck nipple, hose, and
passages
within
the
bottle
for
vacuum leak
only. Coolant
return
failure
will
be
evident
by a low
level
in the
radiator.
Reserve
bottle
level
should increase during heat-up.

J9207-31

7 - 6
COOLING
SYSTEM

• COOLING SYSTEM DIAGNOSIS (EXCEPT DIESEL)—CONTINUED
Condition and Checks
Diagnosis

(7) Other possible
causes.
(7) a — If
symptom
occurs
during high speed operation inspect for

plugged
air
inlet
side of the radiator or condenser,

plugged
radiator core tubes, add on A/C package
without
proper radiator, engine not operating
within
specifications,

dragging
brakes,
trailer
towing or
hill
climbing, or an insect screen.
b — If
symptom
occurs
during high or low
speed
operation inspect for: thermostat being stuck
partially
open if ambient

temperature
is
below
70°F
and
the vehicle
has
high

mileage,
plugged
air
inlet
side of the radiator or
condenser, add on
A/C
with
incorrect radiator.

c
— If
symptom
occurs
during low
speed
operation only, inspect the radiator fan drive. Repair as necessary.

TEMPERATURE
GAUGE
READS
HOT.
PRESSURE
CAP
VENTS
RESULTING
IN
STEAM
AND
COOLANT
TRANSFER
TO

COOLANT
RESERVE
TANK.
(1) Coolant
level
low in radiator and coolant reserve tank. (1) a —
Fill
cooling
system
and vent trapped air.
b — Inspect for leaks. Repair as necessary.

c
—
Ensure
that
pressure cap
is
completely shut and
seals.

d
— If
level
is low in radiator but normal in the coolant reserve tank, check the
filler
cap to coolant reserve
bottle

connection and pressure cap seal.
(2) Test coolant
freeze
point. (2) Adjust coolant to
50/50
mix of
anti-freeze
and
water.
Refer to

Coolant
section in this group.
(3)
Ensure
coolant
is
flowing through system. (3) a — With the coolant
level
low and the thermostat open, check
for coolant flow through the radiator at the
filler
neck.
b — If a
metal
cracking
sound
is heard, inspect for core sand restricting coolant flow through the
water
jacket
and/or a

faulty
cylinder head casting.
(4) Thermostat stuck in the
closed
position
(prevalent
in cold ambient temperatures). (4) Replace thermostat if found to be stuck in
closed
position.
Refer
to the Thermostat Testing section in this group.
(5) Cylinder head gasket leak. (5) Inspect for leaking cylinder head gasket
with
a commercially
available Block Leak Tester.
J9007-57

•

COOLING
SYSTEM
7 - 7 COOLING SYSTEM DIAGNOSIS (EXCEPT DIESELJ-GONTINUED

CONDITION
AND
CHECKS
DIAGNOSIS

TEMPERATURE
GAUGE
IS
INCONSISTENT,
CYCLES
AND/OR
IS
ERRATIC.

(1) Is cycle normal.
MID

(a)
Normal Gauge Reaction to Thermostat Cycle.

MID

(b) Normal Gauge Reaction at Stop After Heavy Use.
(c) Hot Water Build-Up is Normal at
Stop
after
Heavy Use.
(2)
Is
coolant in radiator low (air
will
build up in the cooling
system
(2)
Fill
system,
vent trapped air and check for leaks,
and
cause
the thermostat to open
late).

(3)
Is
a cylinder head gasket leak allowing exhaust
gas
to
enter
(3) a — Test for leaking cylinder head
gasket
leak
with
a
cooling
system
(exhaust
gas
building up in the cooling
system
will
commercially available Block Leak Tester,

cause
the thermostat to open
late).

b
— Check for coolant in engine oil.

c
— Inspect for
white
steam from exhaust
system.

(4)
Water pump impeller loose on shaft.
Loose
accessory
drive belt. (4) Repair or replace as necessary.

(5)
Air leak
on
the
suction
side of the
water
pump (allows air to build (5) Find leak and repair,
up
in cooling
system
causing
thermostat to open
late).

WARNING
LIGHT
GLOWS
ALL
THE
TIME
(VEHICLE
NOT
EQUIPPED
WITH
GAUGE).

(1) Inspect
temperature
gauge
sending
unit. The warning light
sending
(1)
Ensure
that
a warning light
sending
unit
is
installed, unit
has
a screwdriver slot in the electrode (used for calibration).

Gauge
sending
units do not have a slot in the electrode.

NO
GAUGE
READING
INITIALLY
THEN
HOT
INDICATION

(VEHICLE
EQUIPPED
WITH
GAUGE).

(1)
Gauge
stationary
until
very hot, then
moves
immediately to "H"
(1)
Vehicle
is
equipped
with
sending
unit for light not
gauge.
J9007-70

7 - 8
COOLING
SYSTEM

COOLING SYSTEM DIAGNOSIS (EXCEPT DIESEL)—CONTINUED

Condition and Check
Diagnosis

PRESSURE
CAP
VENTS
TO
ATMOSPHERE
AND COOLANT

RESERVE
TANK.
TEMPERATURE
GAUGE
READING
ABOVE

NORMAL
BUT NOT HIGH.
(1) Test radiator pressure cap
relief
pressure. Refer to Radiator Pressure cap section in this group. (1) Replace cap if
relief
pressure is lower than 14 psi.

COOLANT
LOSS
VISIBLE
ON
GROUND
BELOW
VEHICLE,
BUT
NO
PRESSURE
CAP
BLOW
OFF.
(1) Inspect
system
for leaks. (1) Repair as necessary.

COOLANT
LOSS
PAST
PRESSURE
CAP
TOP
SEAL,
VISIBLE
ON
RADIATOR
FILLER
NECK.

(1) With normal gauge reading. (1) a — Pressure cap not installed tightly.
b — Pressure cap top seal leaks.

c
— Pressure cap diaphragm bowed.
d — Damaged radiator
filler
neck.
e — Pressure cap top seal out of position.
(2) With high or low gauge reading on new vehicle. (2) a — Kinked coolant reserve
system
hose.
b — Coolant reserve
system
tank
plastic
tube
plugged,

c
— Pressure cap seal out of position.

DETONATION
OR
PREIGNITION.
NOT
CAUSED
BY IGNITION

OR
ENGINE
CONDITIONS.

(1) Check engine coolant
freeze
point. If the
tester
does
not register a reading or if
the
reading
is
below
50°F,
inspect
ethylene-

glycol/water
ratio.
A 100
percent
solution of ethylene-glycol in
the
system
causes
the engine to run
hotter
and
possibly
overheat. (1) a — Adjust coolant solution to
50/50
water
ethylene-glycol

mixture.

b — If 100
percent
ethylene-glycol solution
is
found in system, clean and flush
system
before
replacing
with
50/50
mixture
of ethylene-glycol and
water.

COOLING
SYSTEM
HOSES
COLLAPSE
ON
COOLDOWN.

(1) Inspect pressure cap
vent
valve. (1) a — Gasket swell can
prevent
valve from opening,
b — Replace pressure cap.
(2) Coolant reserve
tank
hose plugged or kinked. (2) Repair as necessary.
(3) Inside of pressure cap plugged. (3) Clean cap or replace if necessary.

COOLING
SYSTEM
SUSPECTED
AS
CAUSE
OF
INADEQUATE

AIR
CONDITIONING
SYSTEM
PERFORMANCE.

(1) Inspect for plugged radiator and/or condenser. (1) Clean
with
low pressure
water
from fan side.
(2) Inspect for
missing
air
seals
in the recirculating air path. (2) Repair as necessary.

EXCESSIVE
FAN
NOISE

(1) Inspect for loose or
bent
fan blades. (1) Replace fan.
(2) Inspect clearance
between
fan and adjacent
part.
(2) Repair or replace as necessary.
(3) Inspect radiator and condenser for incoming air obstructions. (3) Clean air path
with
low pressure
water
from fan side.
(4) Inspect
viscous
fan drive. (4) Replace if
viscous
drive
does not
operate
properly.

HEAT
ODOR

(1) Was
temperature
gauge reading
high?
(1) If
YES,
refer
to
GAUGE
READING
HIGH. If NO,
refer
to steps
2, 3, and 4.
(2) Are all
heat
shields in place? (2) If
YES,
refer
to
steps
3 and 4. If NO,
repair
as required.
(3) If the air side of the
heat
exchanger
plugged?
(3) Clean as necessary.
(4) Engine running rich
causing
catalytic converter to overheat. (4) Repair as necessary.

POOR
DRIVEABIUTY.
SUSPECT
THERMOSTAT
FAILED
IN
OPEN
POSITION.

(1) Check On-Board
Diagnostics.
Is code 17 set in memory? (1) If
YES,
replace thermostat. If NO,
refer
to the appropriate
Driveability Manual.

J9007-59

7-10 COOLING SYSTEM
•
DIESEL
COOLING SYSTEM
DIAGNOSIS

CONDITION AND CHECKS
DIAGNOSIS

OPTIONAL
60»F
GAUGE
READS
LOW 30° TO 40°
GAUGE
TRAVEL
IS
NORMAL
(1)
Verify
gauge reading. Is a low
temperature
indicated?
(2) Thermostat stuck in open position?
(3) Is the gauge reading in the cold range?
(4) Low coolant
level
during cold ambient temperatures (accom­ panied
with
poor
heater
performance).
(5) Coolant
level
is correct.
MID

Normal
Gauge
Travel

(1) Inspect
temperature
gauge sending unit. Refer to Group 8,
Electrical. Repair or replace sending
unit
as necessary.
(2) If
Yes,
replace the thermostat. If not, the thermostat is not the
cause
of the low gauge
reading.

(3) Inspect for disconnected sending
unit
electrical
connector or
incorrect
sending unit. Ensure
that
gauge sending
unit
is in­
stalled and not an indicator light switch.
(4) WARNING: DO NOT REMOVE THE RADIATOR CAP
OF
A HOT, PRESSURIZED ENGINE. SERIOUS IN­
JURY CAN RESULT FROM SCALDING COOLANT. Inspect coolant
level
in the coolant reserve tank and radiator. Inspect system for leaks.
(5) Inspect
heater
door
controls.
Refer to Group 24, Heating and
Air Conditioning.

GAUGE
READING HIGH. NO PRESSURE BLOW OFF FROM RADIATOR PRESSURE CAP OR STEAM FROM
COOLANT
RESERVE
TANK.
X

(1)
Verify
gauge reading. Is a high
temperature
reading indi­
cated?

(2) Gauge reading at "H"
without
signs
of boiling.
(3) Low coolant
level
in radiator and coolant reserve tank.
MAXIMUM
HOT

WEATHER

HEAVY
LOAD

MAXIMUM
UP

TO
TOP AMBIENT High Gauge
Reading
— Hot
Weather
—
Heavy
Load

(1) Compare gauge reading to High Gauge Reading Illustration
above.
(2) Inspect for grounded
gauge,
sending
unit
or circuit. Refer to

Group
8, Electrical.
(4) Coolant
level
in radiator
is
low.
But
not low in coolant reserve tank.
(5) Test coolant
freeze
point. (3) a-
b — (4) a-
b —
d —
(5) a- (6) Ensure proper coolant flow.
(6) a-
b —
Fill
to
full.

Inspect for leaks in system and
repair

as
necessary.
Ensure
radiator pressure cap was shut
tight.
Verify
proper operation of the radiator

cap
upper and lower
seals.
Fill
to
full.

Inspect for leaks in the system and
repair

as
necessary.
Inspect for leaks in the coolant reserve
tank to radiator hose.
Verify
proper operation of the radiator cap
upper and lower
seals.

Adjust coolant solution to
50/50
mixture
of
anti-freeze
and
water.
Refer to Coolant
in this group. If a reading is not recorded or below - 50.
the
mixture
is too rich. Clean system and
fill

with
a
50/50
mixture
of
anti-freeze
and
water.
Refer to Coolant in this group.
With the thermostat open and a slight amount
of coolant removed, inspect for coolant flow
through the radiator at the
filler
neck opening. Determine reason for lack of coolant flow
and
repair
as necessary.
J9107-22

•

COOLING
SYSTEM
7-11 DIESEL COOLING SYSTEM DIAGNOSIS-CONTINUED
Condition and Chocks
Diagnosis

(7) Other possible
causes.
(7) a — If
symptom
occurs
during high speed operation inspect for

plugged
air
inlet
side of the radiator or condenser,

plugged
radiator core tubes, add on
A/C
package without
proper radiator, engine not operating
within
specifications,

dragging
brakes,
trailer
towing or
hill
climbing, or an insect screen.
b — If
symptom
occurs
during
high
or low speed operation inspect for: thermostat being stuck
partially
open if ambient

temperature
is
below 70°F
and
the vehicle
has
high

mileage,
plugged
air
inlet
side of the radiator or
condenser, add on
A/C
with
incorrect radiator.

c
— If
symptom
occurs
during low
speed
operation only, inspect the radiator fan drive. Repair
as
necessary.

TEMPERATURE
GAUGE
READS
HOT.
PRESSURE
CAP VENTS
RESULTING
IN
STEAM
AND COOLANT
TRANSFER
TO

COOLANT
RESERVE
TANK.

(1)
Coolant
level
low in radiator and coolant reserve tank. (1) a —
Fill
cooling
system
and vent trapped air.
b — Inspect for leaks. Repair as necessary.

c
—
Ensure
that
pressure cap
is
completely shut and
seals.

d
— If
level
is low in radiator but normal in the coolant reserve tank, check the
filler
cap to coolant reserve
bottle
connection and pressure cap seal.
(2) Test coolant
freeze
point. (2) Adjust coolant to 50/50 mix of
anti-freeze
and
water.
Refer to

Coolant
section
in this group.
(3)
Ensure
coolant
is
flowing through system. (3) a — With the coolant
level
low and the thermostat open, check
for coolant flow through the radiator at the
filler
neck.
b — If a
metal
cracking
sound
is
heard, inspect for core sand restricting coolant flow through the
water
jacket
and/or a

faulty
cylinder head casting.
(4) Thermostat stuck in the
closed
position (prevalent in cold ambient temperatures). (4) Replace thermostat if found to be stuck in
closed
position. Refer
to the Thermostat Testing section in this group.
(5) Cylinder head gasket leak. (5) Inspect for leaking cylinder head
gasket
with
a commercially
available Block Leak Tester.
J9007-57

•
COOLING SYSTEM 7-13
DIESEL COOLING SYSTEM DIAGNOSIS-CONTINUED

CONDITION
AND
CHECKS
DIAGNOSIS

COOLANT
LOSS
PAST
PRESSURE
CAP
TOP
SEAL,

VISIBLE
ON
RADIATOR
FILLER
NECK.
(1)
With
normal gauge reading. (1) a — Pressure cap not installed
tightly.

b — Pressure cap top seal leaks.

c
— Pressure cap diaphragm bowed.

d
— Damaged
radiator
filler
neck.
e — Pressure cap top seal out of position.
(2)
With
high or low gauge reading on new vehicle. (2) a — Kinked coolant reserve system hose.
(2)
With
high or low gauge reading on new vehicle.
b — Coolant reserve system
tank
plastic
tube
plugged.

c
— Pressure cap seal out of position.

DETONATION
OR
PREIGNITION.
NOT
CAUSED
BY
IGNI­

TION OR
ENGINE
CONDITIONS.

(1)
Check engine coolant
freeze
point.
If the
tester
does
not
regis­
(1) a — Adjust coolant solution to
50/50
water

ter a reading or if the reading is below 50°F, inspect
ethyl­
ethylene-glycol
mixture.

ene-glycol/
water
ratio.
A 100
percent
solution of
ethylene-
b — If 100
percent
ethylene-glycol
solution is found
glycol
in
the
system
causes
the engine
to
run
hotter
and
possi­
in system,
clean
and flush system
before

bly overheat.
replacing
with
50/50
mixture
of

ethylene-glycol
and
water.

COOLING
SYSTEM
HOSES
COLLAPSE
ON
COOLDOWN.
(1) Inspect pressure cap
vent
valve. (1) a — Gasket swell can
prevent
valve
from
opening.
b — Replace pressure cap.
(2) Coolant reserve
tank
hose plugged or kinked. (2) Repair as necessary.
(3) Inside of pressure cap plugged. (3) Clean cap or
replace
if necessary.

COOLING
SYSTEM
SUSPECTED
AS
CAUSE
OF
INADE­
QUATE
AIR CONDITIONING
SYSTEM
PERFORMANCE.

(1) Inspect for plugged
radiator
and/or condenser. (D Clean
with
low pressure
water
from
fan side.
(2) Inspect for
missing
air
seals
in the
recirculating
air path. (2) Repair
as
necessary.

EXCESSIVE
FAN
NOISE

(1)
Inspect for loose or
bent
fan blades. (1) Replace fan.
(2) Inspect clearance
between
fan and
adjacent
part.
(2) Repair or
replace
as necessary.
(3) Inspect
radiator
and condenser for incoming air obstructions. (3) Clean air path
with
low pressure
water
from
fan side.
(4) Inspect
viscous
fan drive. (4) Replace if
viscous
drive
does not
operate
properly.

HEAT
ODOR

(1)
Was
temperature
gauge reading high? (1) If
YES,
refer
to
GAUGE
READING
HIGH.
If
NO,
refer
to
steps

2, 3, and 4.
(2) Are all
heat
shields in place? (2) If
YES,
refer
to steps 3 and 4. If NO,
repair
as
required.

(3)
Is
the air side of the
heat
exchanger plugged? (3) Clean as necessary.
(4) Engine running rich causing
catalytic
converter
to overheat. (4) Repair
as
necessary.

POOR
DRIVEABILITY.
SUSPECT
THERMOSTAT FAILED
IN OPEN POSITION.

(1)
Thermostat stuck in open position? 01 Replace thermostat. ._ _0 .
Jy
107-24

•

COOLING SYSTEM
7 - 15
SERVICE
PROCEDURES

INDEX
page
Coolant
26
Coolant Reserve/Overflow System
30

Cooling System Cleaning/Reverse Flushing
28

Cooling System Fan—Diesel Engine
. 37

Cooling System
Fan—Gas
Engines
36

Cooling System
Hoses
34
Draining Cooling System
27

Pressure
Testing
Radiator
Caps
............. 32

Radiator Pressure
Cap 31

Radiators
32

Refilling
the
Cooling System
28

WATER PUMPS—EXCEPT DIESEL
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core.
The pump is driven from the engine crankshaft by a drive belt. The water pump impeller is pressed onto the rear
of a shaft that rotates in a bearing pressed into the
water pump body. The body has a small hole for ven­
tilation. The water pump seals are lubricated by an­
tifreeze in the coolant mixture. Additional lubrication is not necessary. A quick test to determine if pump is working is to
check if heater warms properly. A defective water
pump will not be able to circulate heated coolant
through the long heater hose to the heater core. The water pump on all models can be removed
without discharging the air conditioning system (if equipped).
REMOVAL The water pump on all gas powered engines is
bolted directly to the engine timing chain case/cover.
A gasket is used as a seal between the water pump
and timing chain case/cover.
If water pump is replaced because of bearing/shaft
damage or leaking shaft seal, the mechanical cooling
fan assembly should also be inspected. Inspect for fa­ tigue cracks, loose blades or loose rivets that could
have resulted from excessive vibration. Replace fan if any of these conditions are found. Also check condi­
tion of the thermal viscous fan drive. Refer to Vis­
cous Fan Drive in this group. (1) Disconnect negative battery cable from battery.
(2) Drain cooling system. Refer to Draining Cool­
ing System in this group. Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
(3)
Disconnect throttle cable from clip at top of fan
shroud.
page

Testing
Cooling System
for
Leaks
. 29

Thermostat
22

Transmission
Oil
Cooler—Diesel
35

Transmission
Oil
Cooler—Except Diesel
35

Transmission Oil-To-Air Cooler
36
Viscous
Fan
Drive
38

Water
Pump
Bypass
Hose—All
Gas
Powered
Engines
.............................. 19

Water
Pumps—5.9L Diesel
18

Water
Pumps—Except Diesel
15
(4) Unsnap coolant reserve/overflow tank (up and
out) from the T-slots on side of fan shroud (Fig. 1) and lay aside. Do not disconnect hose or drain cool­
ant from tank.
(5) Remove the fan shroud from the radiator. Do
not remove shroud from vehicle at this time.
FAN

SHROUD
J9107-67

Fig.
1 Fan
Shroud—Except
Diesel

(6) Remove upper radiator hose at radiator. Special
Clamp Tool number 6094 (Fig. 2) may be used to re­
move the constant tension clamps.
(7) The thermal viscous fan drive is attached
(threaded) to the water pump hub shaft (Fig. 3). Re­
move the fan/fan drive assembly from water pump by
turning the mounting nut counterclockwise (as viewed from front). Threads on the fan drive are RIGHT HAND. A Snap-On 36 MM Fan Wrench (number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used. Place a bar or
screwdriver between the water pump pulley bolts (Fig. 3) to prevent the pulley from rotating.
If water pump is being replaced, do not unbolt fan
blade assembly (Fig. 3) from the thermal control fan drive.

7 - 18
COOLING
SYSTEM

• (9) Relax tension from automatic belt tensioner

(Figs.
4 or 5). Install drive belt.

CAUTION:
When
installing
the
serpentine
accessory

drive
belt, belt
must
be
routed
correctly.
If not, en­

gine
may
overheat
due to
water
pump
rotating
in

wrong
direction.
Refer
to
(Figs,
i, 10 or 11) for
cor­
rect
belt
routing.
The
correct
belt with
correct

length
must
be
used.

*IF
VEHICLE
IS NOT
EQUIPPED
WITH
POWER
STEERING,
THIS
WILL
BE
AN
IDLER
PULLEY.
J9307-26
Fig.
9 Belt Routing—3.9U5.2L/5.9L
LDC-Gas
Engine

AUTOMATIC
TENSIONER
AUTOMATIC

TENSIONER

J9307-56

Fig.
11 Belt Routing—5.9L
HDC-Gas
Engine—Without
A/C (10) Position fan shroud and fan blade/viscous fan
drive assembly to vehicle as a complete unit. (11) Install fan shroud.
(12) Install fan blade/viscous fan drive assembly to
water pump shaft.
(13) Fill cooling system. Refer to Refilling Cooling
System in this group. (14) Connect negative battery cable.
(15) Start and warm the engine. Check for leaks.

WATER
PUMPS—5.9L
DIESEL
The diesel engine water pump draws coolant from
radiator outlet and circulates it through engine,
heater core and back to radiator inlet. The crank­ shaft pulley drives the water pump via a serpentine
drive belt (Fig. 12). An automatic belt tensioner (Fig. 12) is used to prevent the belt from slipping.
REMOVAL (1) Disconnect the negative battery cable at bat­
tery. (2) Drain cooling system. Refer to Draining Cool­
ing System in this section.
(3) Remove the accessory drive belt. Refer to the
Engine Accessory Drive Belt section of this group. (4) Remove water pump mounting bolts (Fig. 13).
(5) Clean water pump sealing surface on cylinder
block.
J9307-55

Fig.
10 Belt Routing—5.9L
HDC-Gas
Engine-With

A/C
INSTALLATION

(1) Install new O-ring seal in groove on water
pump (Fig. 14). (2) Install water pump. Tighten mounting bolts to
24 N-m (18 ft. lbs.) torque.