heating DODGE RAM 1500 1998 2.G User Guide

Inspect the adjuster screw assembly. Replace the
assembly if the star wheel or threads are damaged,
or the components are severely rusted or corroded
(Fig. 77).
Discard the brake springs and retainer components
if worn, distorted or collapsed. Also replace the
springs if a brake drag condition had occurred. Over-
heating will distort and weaken the springs.
Inspect the brake shoe contact pads on the support
plate, replace the support plate if any of the pads are
worn or rusted through. Also replace the plate if it is
bent or distorted (Fig. 77).
INSTALLATION
NOTE: On a new vehicle or after parking brake lin-
ing replacement, it is recommended that the park-
ing brake system be conditioned prior to use. This
is done by making one stop from 25 mph on dry
pavement or concrete using light to moderate force
on the parking brake foot pedal.
(1) Reassemble the rear park brake shoes (Fig. 67)
or (Fig. 78).
(2) Install the axleshaft (Fig. 76) (Refer to 3 - DIF-
FERENTIAL & DRIVELINE/REAR AXLE - 9 1/4/
AXLE SHAFTS - INSTALLATION) or (Refer to 3 -
DIFFERENTIAL & DRIVELINE/REAR AXLE - 11
1/2 AA/10 1/2 AA/AXLE SHAFTS - INSTALLATION).
(3) Install the park brake cable to the lever behind
the support plate.
(4) Unlock the park brake cable.
(5) Install the disc brake rotor (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTORS -
INSTALLATION).(6) Install the disc brake caliper (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPERS - INSTALLATION).
(7) Adjust the rear brake shoes (Refer to 5 -
BRAKES/PARKING BRAKE/SHOES - ADJUST-
MENTS).
Fig. 76 AXLE SHAFT
1 - AXLE SHAFT
2 - SUPPORT PLATE
3 - CALIPER
4 - PARK BRAKE SHOE ASSEMBLY
Fig. 77 PARK BRAKE SHOES
1 - SUPPORT PLATE
2 - SHOES
3 - RETURN SPRINGS
4 - RETAINER CLIPS
5 - ADJUSTER
Fig. 78 SHOE ASSEMBLY
1 - Park Brake Shoes
2 - Hold Downs
3 - Return Springs
5 - 40 BRAKES - BASEDR
SHOES (Continued)

Engagement problems can cause slip, chatter/shud-
der and noisy operation. The causes may be clutch
disc contamination, wear, distortion or flywheel dam-
age.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage
of any clutch component will cause grab, chatter and
improper clutch release.
CLUTCH COVER AND DISC RUNOUT
Check the clutch disc before installation. Axial
(face) runout of anewdisc should not exceed 0.50
mm (0.020 in.). Measure runout about 6 mm (1/4 in.)
from the outer edge of the disc facing. Obtain
another disc if runout is excessive.
Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab
and incomplete release or engagement. Be careful
when handling the cover and disc. Impact can distort
the cover, diaphragm spring, release fingers and the
hub of the clutch disc.
Use an alignment tool when positioning the disc on
the flywheel. The tool prevents accidental misalign-
ment which could result in cover distortion and disc
damage.
A frequent cause of clutch cover distortion (and
consequent misalignment) is improper bolt tighten-
ing.
FLYWHEEL RUNOUT
Check flywheel runout whenever misalignment is
suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of
the flywheel face with a dial indicator.
Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. Minor fly-
wheel scoring can be cleaned up by hand with 180
grit emery or with turning equipment. Remove only
enough material to reduce scoring (approximately
0.001 - 0.003 in.). Heavy stock removal isnot 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 fly-
wheel and interfere with proper clutch release.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal or equivalent.
Tighten flywheel bolts to specified torque only. Over-
tightening can distort the flywheel hub causing
runout.
DIAGNOSIS CHART
The diagnosis charts Diagnosis Chart describe
common clutch problems, causes and correction.
DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Disc facing worn out 1. Normal wear. 1. Replace cover and disc.
2. Driver frequently rides (slips) the
clutch. Results in rapid overheating
and wear.2. Replace cover and disc.
3. Insufficient clutch cover
diaphragm spring tension.3. Replace cover and disc.
6 - 2 CLUTCHDR
CLUTCH (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
Clutch disc facing contaminated with
oil, grease, or clutch fluid.1. Leak at rear main engine seal or
transmission input shaft seal.1. Replace appropriate seal.
2. Excessive amount of grease
applied to the input shaft splines.2. Remove grease and apply the
correct amount of grease.
3. Road splash, water entering
housing.3. Replace clutch disc. Clean clutch
cover and reuse if in good condition.
4. Slave cylinder leaking. 4. Replace hydraulic clutch linkage.
Clutch is running partially
disengaged.1. Release bearing sticking or
binding and does not return to the
normal running position.1. Verify failure. Replace the release
bearing and transmission front
bearing retainer as necessary.
Flywheel below minimum thickness
specification.1. Improper flywheel machining.
Flywheel has excessive taper or
excessive material removal.1. Replace flywheel.
Clutch disc, cover and/or diaphragm
spring warped or distorted.1. Rough handling. Impact bent
cover, spring, or disc.1. Replace disc or cover as
necessary.
2. Improper bolt tightening
procedure.2. Tighten clutch cover using proper
procedure.
Facing on flywheel side of disc torn,
gouged, or worn.1. Flywheel surface scored or
nicked.1. Correct surface condition if
possible. Replace flywheel and disc
as necessary.
2. Clutch disc sticking or binding on
transmission input shaft.2. Inspect components and
correct/replace as necessary.
Clutch disc facing burnt. Flywheel
and cover pressure plate surfaces
heavily glazed.1. Frequent operation under high
loads or hard acceleration
conditions.1. Correct condition of flywheel and
pressure plate surface. Replace
clutch cover and disc. Alert driver to
problem cause.
2. Driver frequently rides (slips)
clutch. Results in rapid wear and
overheating of disc and cover.2. Correct condition of flywheel and
pressure plate surface. Replace
clutch cover and disc. Alert driver to
problem cause.
Clutch disc binds on input shaft
splines.1. Clutch disc hub splines damaged
during installation.1. Clean, smooth, and lubricate hub
splines if possible. Replace disc if
necessary.
2. Input shaft splines rough,
damaged, or corroded.2. Clean, smooth, and lubricate
shaft splines if possible. Replace
input shaft if necessary.
Clutch disc rusted to flywheel and/or
pressure plate.1. Clutch not used for an extended
period of time (e.g. long term
vehicle storage).1. Sand rusted surfaces with 180
grit sanding paper. Replace clutch
cover and flywheel if necessary.
DRCLUTCH 6 - 3
CLUTCH (Continued)

Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. Minor fly-
wheel scoring can be cleaned up by hand with 180
grit emery or with surface grinding equipment.
Remove only enough material to reduce scoring
(approximately 0.001 - 0.003 in.). Heavy stock
removal isnot recommended.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.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal or equivalent.
Tighten flywheel bolts to specified torque only. Over-
tightening can distort the flywheel hub causing
runout.
REMOVAL
(1) Remove transmission.
(2) Remove pressure plate and clutch.
(3) Remove flywheel bolts and remove flywheel.
DISASSEMBLY
NOTE: If the teeth are worn or damaged, the fly-
wheel should be replaced as an assembly. This is
the recommended repair. In cases where a new fly-
wheel is not readily available, (V10/Diesel Engine
only) a replacement ring gear can be installed. The
following procedure must be observed to avoid
damaging the flywheel and replacement gear.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES WHILE CUTTING RING GEAR.
(1) Mark position of the old gear for alignment ref-
erence on the flywheel. Use a scriber for this pur-
pose.
(2) 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.
ASSEMBLY
NOTE: 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. Every
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 approxi-
mately 375É F.
CAUTION: Do not use an oxy/acetylene torch to
remove the old gear, or to heat and expand a new
gear. The high temperature of the torch flame can
cause localized heating that will damage the fly-
wheel. In addition, using the torch to heat a replace-
ment gear will cause uneven heating and
expansion. The torch flame can also anneal the
gear teeth resulting in rapid wear and damage after
installation.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES AND HEAT RESISTENT GLOVES
WHEN HANDLING A HEATED RING GEAR.
(1) The heated gear must be installed evenly to
avoid misalignment or distortion.
(2)
Position and install the heated ring gear on the
flywheel with a shop press and a suitable press plates.
(3) Place flywheel on work bench and let it cool in
normal shop air. Allow the ring gear to cool down
completely before installation it on the engine.
CAUTION: Do not use water or compressed air to
cool the flywheel. The rapid cooling produced by
water or compressed air will distort or crack the
new gear.
INSTALLATION
(1) Install flywheel on the crank shaft.
(2) Install flywheel bolts and tighten to 95 N´m
(70 ft. lbs.).
(3) Install clutch.
(4) Install transmission.
PILOT BEARING
REMOVAL
(1) Remove transmission.
(2) Remove clutch disc.
(3) Use a suitable blind hole puller to remove pilot
bearing.
DRCLUTCH 6 - 11
FLYWHEEL (Continued)

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE..................1
DESCRIPTION - COOLING SYSTEM FLOW -
5.9L DIESEL..........................3
DESCRIPTION - HOSE CLAMPS...........3
OPERATION
OPERATION - COOLING SYSTEM.........5
OPERATION - HOSE CLAMPS............5
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)...................5
DIAGNOSIS AND TESTING - COOLING
SYSTEM - TESTING FOR LEAKS..........5
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIESEL ENGINE................7
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS............................10
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT
LEVEL CHECK........................17STANDARD PROCEDURE - COOLING
SYSTEM CLEANING/REVERSE FLUSHING . . 17
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM - ALL GAS ENGINES . . . 17
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM - ALL GAS ENGINES . . . 18
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 18
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................19
SPECIFICATIONS
TORQUE............................19
SPECIFICATIONS -....................20
SPECIAL TOOLS
COOLING...........................20
ACCESSORY DRIVE......................21
ENGINE...............................30
TRANSMISSION.........................67
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L/5.7L ENGINE
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.The cooling system provides a means of heating
the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant through the system. The
coolant recovery/reserve system utilizes an ambient
overflow bottle (Fig. 2).
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures (Fig. 1).
DRCOOLING 7 - 1

OPERATION
OPERATION - COOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
All engines utilize an ambient overflow bottle for
coolant recovery/reserve.
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures.
OPERATION - HOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The Engine Control Module (ECM) has been pro-
grammed to monitor certain cooling system compo-
nents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.
²If an open or shorted condition has developed in
the electronically controlled viscous fan clutch circuit,
a Diagnostic Trouble Code (DTC) can be set.
²If fan speed is not detected a DTC will be set.
²Coolant temperature sensor circuit problems can
set a DTC.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the ECM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the
DRBIIItscan tool to erase a DTC. Refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice information for operation of the DRBIIItscan
tool.
DIAGNOSIS AND TESTING - COOLING SYSTEM
- TESTING FOR LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate the engine until the radi-
ator upper hose is warm to the touch. Aim the com-
mercially available black light tool at the components
to be checked. If leaks are present, the black light
will cause the additive to glow a bright green color.
The black light can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 5).
Fig. 4 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
DRCOOLING 7 - 5
COOLING (Continued)

exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINECOOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of the top of the thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
DIAGNOSIS AND TESTING - COOLING SYSTEM DIESEL ENGINE
COOLING SYSTEM DIAGNOSIS - DIESEL ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READS
LOW1. Vehicle is equipped with a heavy
duty cooling system.1. None. System operating normally.
NOTE: Information on dash cluster
is displayed based on broadcast
datd from ECM. DTC will be set for
engine sensore circuit concern.2. Thermostat stuck open 2. Inspect and test thermostat.
3. Coolant level low. 3. Fill cooling system. (Refer to 7 -
COOLING - STANDARD
PROCEDURE)
4. Temperature gauge not
functioning correctly.4. Check cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
5. Engine sensor stuck in range 5. Monitor sensor with DRB III to
verify sensor reading changes with
increasing temperature.
6. Engine sensor failed out of
range.A DTC will be set.
7. Electronically Controlled Vicsous
Fan Drive not operating properly.7. Check Electronically Controlled
Viscous Fan Drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
DRCOOLING 7 - 7
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
INADEQUATE AIR CONDITIONER
PERFORMANCE (COOLING
SYSTEM SUSPECTED)1. Radiator and/or A/C condenser
air flow obstructed.1. Remove obstruction and/or clean.
2. Electronically controlled viscous
fan drive not working.2. Check viscous fan drive (Refer to
7 - COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
3. Air seals around radiator
damaged or missing.3. Inspect air seals, repair or
replace as necessary.
INADEQUATE HEATER
PERFORMANCE. GAUGE MAY OR
MAY NOT READ LOW.1. Heavy duty cooling system, and
cooler ambient temperatures.1. None. Normal condition.
2. Obstruction in heater hoses. 2. Remove hoses, remove
obstruction.
3. Electronically controlled viscous
fan stuck on.Check viscous fan drive. (Refer to 7
- COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
4. Water pump damaged. 4. Replace water pump.
HEAT ODOR 1. Damaged or missing drive line
heat shields.1. Repair or replace damaged or
missing heat shields.
2. Electronically controlled viscous
fan drive damaged.2. Check viscous fan drive. (Refer
to 7 - COOLING/ENGINE/FAN
DRIVE VISCOUS CLUTCH -
DIAGNOSIS AND TESTING)
DIAGNOSIS AND TESTING - 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:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED OR STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
²Increasing engine speed for more air flow is rec-
ommended.
TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect the cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
²Service to electrically controlled viscous fan
clutch
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to COOLING SYSTEM DIAGNOSIS
CHART BELOW.
These charts are to be used as a quick-reference
only. Refer to COOLING SYSTEM DIAGNOSIS
CHART
7 - 10 COOLINGDR
COOLING (Continued)

COOLING SYSTEM DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READS
LOW1. Has a Diagnostic Trouble Code
(DTC) been set indicating a stuck
open thermostat?1. (Refer to 25 - EMISSIONS
CONTROL - DESCRIPTION) for
On-Board Diagnostics and DTC
information. Replace thermostat if
necessary.
2. Is the temperature sending unit
connected?2. Check the temperature sensor
connector. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - SCHEMATIC -
ELECTRICAL) Repair connector if
necessary.
3. Is the temperature gauge
operating OK?3. Check gauge operation. (Refer to
8 - ELECTRICAL/INSTRUMENT
CLUSTER/ENGINE
TEMPERATURE GAUGE -
DESCRIPTION). Repair as
necessary.
4. Coolant level low in cold ambient
temperatures accompanied with
poor heater performance.4. Check coolant level in the coolant
reserve/overflow tank or degas
bottle and the radiator. Inspect
system for leaks. Repair leaks as
necessary. Refer to the Coolant
section of the manual text for
WARNINGS and CAUTIONS
associated with removing the
radiator cap.
5. Improper operation of internal
heater doors or heater controls.5. Inspect heater and repair as
necessary. (Refer to 24 - HEATING
& AIR CONDITIONING -
DIAGNOSIS AND TESTING) for
procedures.
TEMPERATURE GAUGE READS
HIGH OR THE COOLANT
WARNING LAMP ILLUMINATES.
COOLANT MAY OR MAY NOT BE
LOST OR LEAKING FROM THE
COOLING SYSTEM1. Trailer is being towed, a steep
hill is being climbed, vehicle is
operated in slow moving traffic, or
engine is being idled with very high
ambient (outside) temperatures and
the air conditioning is on. Higher
altitudes could aggravate these
conditions.1. This may be a temporary
condition and repair is not
necessary. Turn off the air
conditioning and attempt to drive the
vehicle without any of the previous
conditions. Observe the temperature
gauge. The gauge should return to
the normal range. If the gauge does
not return to the normal range,
determine the cause for overheating
and repair. Refer to Possible
Causes (2-18).
2. Is the temperature gauge reading
correctly?2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - SCHEMATIC -
ELECTRICAL). Repair as
necessary.
DRCOOLING 7 - 11
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
11. Radiator core is corroded or
plugged.11. Have radiator re-cored or
replaced.
12. Fuel or ignition system
problems.12. Refer to 14 - Fuel System or 8 -
Electrical for diagnosis and testing
procedures.
13. Dragging brakes. 13. Check and correct as
necessary. (Refer to 5 - BRAKES -
DIAGNOSIS AND TESTING) for
correct procedures.
14. Bug screen or cardboard is
being , reducing air flow.14. Remove bug screen or
cardboard.
15. Thermostat partially or
completely shut.15. Check thermostat operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT -
REMOVAL) .
16. Viscous fan drive not operating
properly.16. Check fan drive operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - REMOVAL).
17. Cylinder head gasket leaking. 17. Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
18. Heater core leaking. 18. Check heater core for leaks.
(Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING).
Repair as necessary.
DRCOOLING 7 - 13
COOLING (Continued)