engine coolant JEEP LIBERTY 2002 KJ / 1.G Workshop Manual

FASTENER USAGE
DESCRIPTION
DESCRIPTION
WARNING: USE OF AN INCORRECT FASTENER
MAY RESULT IN COMPONENT DAMAGE OR PER-
SONAL INJURY.
Figure art, specifications and torque references in
this Service Manual are identified in metric and SAE
format.
During any maintenance or repair procedures, it is
important to salvage all fasteners (nuts, bolts, etc.)
for reassembly. If the fastener is not salvageable, a
fastener of equivalent specification must be used.
DESCRIPTION
Most stripped threaded holes can be repaired using
a Helicoilt. Follow the vehicle or Helicoiltrecommen-
dations for application and repair procedures.
THREADED HOLE REPAIR
DESCRIPTION
Most stripped threaded holes can be repaired using
a Helicoilt. Follow the vehicle or Helicoiltrecommen-
dations for application and repair procedures.
INTERNATIONAL SYMBOLS
DESCRIPTION
The graphic symbols illustrated in the following
International Control and Display Symbols Chart
(Fig. 3) are used to identify various instrument con-
trols. The symbols correspond to the controls and dis-
plays that are located on the instrument panel.
Fig. 3 INTERNATIONAL CONTROL AND DISPLAY SYMBOLS
1 High Beam 13 Rear Window Washer
2 Fog Lamps 14 Fuel
3 Headlamp, Parking Lamps, Panel Lamps 15 Engine Coolant Temperature
4 Turn Warning 16 Battery Charging Condition
5 Hazard Warning 17 Engine Oil
6 Windshield Washer 18 Seat Belt
7 Windshield Wiper 19 Brake Failure
8 Windshield Wiper and Washer 20 Parking Brake
9 Windscreen Demisting and Defrosting 21 Front Hood
10 Ventilating Fan 22 Rear hood (Decklid)
11 Rear Window Defogger 23 Horn
12 Rear Window Wiper 24 Lighter
4 INTRODUCTIONKJ

LUBRICATION & MAINTENANCE
TABLE OF CONTENTS
page page
INTERNATIONAL SYMBOLS
DESCRIPTION Ð INTERNATIONAL SYMBOLS . . 1
FLUID TYPES
DESCRIPTION
DESCRIPTION - FLUID TYPES............1
DESCRIPTION - AXLE...................2
DESCRIPTION - MANUAL TRANSMISSION . . . 2
DESCRIPTION - AUTOMATIC
TRANSMISSION FLUID..................2
DESCRIPTION - TRANSFER CASE - NV231 . . 3
DESCRIPTION - TRANSFER CASE - NV242 . . 3
DESCRIPTION - ENGINE COOLANT........3
OPERATION - AUTOMATIC TRANSMISSION
FLUID...............................4FLUID CAPACITIES
SPECIFICATIONS - FLUID CAPACITIES.......4
FLUID FILL/CHECK LOCATIONS
DESCRIPTION..........................5
MAINTENANCE SCHEDULES
DESCRIPTION..........................5
HOISTING
STANDARD PROCEDURE - HOISTING
RECOMMENDATIONS...................5
JUMP STARTING
STANDARD PROCEDURE - JUMP STARTING
PROCEDURE.........................6
TOWING
STANDARD PROCEDURE - TOWING.........6
INTERNATIONAL SYMBOLS
DESCRIPTION Ð INTERNATIONAL SYMBOLS
DaimlerChrysler Corporation uses international
symbols to identify engine compartment lubricant
and fluid inspection and fill locations (Fig. 1).
FLUID TYPES
DESCRIPTION
DESCRIPTION - FLUID TYPES
When service is required, DaimlerChrysler Corpo-
ration recommends that only Mopartbrand parts,
lubricants and chemicals be used. Mopartprovides
the best engineered products for servicing
DaimlerChrysler Corporation vehicles.
Only lubricants bearing designations defined by
the following organization should be used to service a
Chrysler Corporation vehicle.
²Society of Automotive Engineers (SAE)
²American Petroleum Institute (API) (Fig. 2)
²National Lubricating Grease Institute (NLGI)
(Fig. 3)
SAE VISCOSITY RATING
An SAE viscosity grade is used to specify the vis-
cosity of engine oil. These are specified with a dual
SAE viscosity grade which indicates the cold-to-hot
temperature viscosity range. Example SAE 5W-30 =
multigrade engine oil.
DaimlerChrysler Corporation only recommends
multigrade engine oils.
Fig. 1 International Symbols
KJLUBRICATION & MAINTENANCE 0 - 1

odor that may change with age. Consequently, odor
and color cannot be used to indicate the fluid condi-
tion or the need for a fluid change.
FLUID ADDITIVES
DaimlerChrysler strongly recommends against the
addition of any fluids to the transmission, other than
those automatic transmission fluids listed above.
Exceptions to this policy are the use of special dyes
to aid in detecting fluid leaks.
Various ªspecialº additives and supplements exist
that claim to improve shift feel and/or quality. These
additives and others also claim to improve converter
clutch operation and inhibit overheating, oxidation,
varnish, and sludge. These claims have not been sup-
ported to the satisfaction of DaimlerChrysler and
these additivesmust not be used.The use of trans-
mission ªsealersº should also be avoided, since they
may adversely affect the integrity of transmission
seals.
DESCRIPTION - TRANSFER CASE - NV231
Recommended lubricant for the NV231 transfer
case is MopartATF +4, type 9602, Automatic Trans-
mission Fluid.
DESCRIPTION - TRANSFER CASE - NV242
Recommended lubricant for the NV242 transfer
case is MopartATF+4, type 9602 Automatic Trans-
mission Fluid.
DESCRIPTION - ENGINE COOLANT
WARNING: ANTIFREEZE IS AN ETHYLENE GLYCOL
BASE COOLANT AND IS HARMFUL IF SWAL-
LOWED OR INHALED. IF SWALLOWED, DRINK
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA.
SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE GLYCOL.
KEEP OUT OF REACH OF CHILDREN. DISPOSE OF
GLYCOL BASE COOLANT PROPERLY, CONTACT
YOUR DEALER OR GOVERNMENT AGENCY FOR
LOCATION OF COLLECTION CENTER IN YOUR
AREA. DO NOT OPEN A COOLING SYSTEM WHEN
THE ENGINE IS AT OPERATING TEMPERATURE OR
HOT UNDER PRESSURE, PERSONAL INJURY CAN
RESULT. AVOID RADIATOR COOLING FAN WHEN
ENGINE COMPARTMENT RELATED SERVICE IS
PERFORMED, PERSONAL INJURY CAN RESULT.
CAUTION: Use of Propylene Glycol based coolants
is not recommended, as they provide less freeze
protection and less corrosion protection.The cooling system is designed around the coolant.
The coolant must accept heat from engine metal, in
the cylinder head area near the exhaust valves and
engine block. Then coolant carries the heat to the
radiator where the tube/fin radiator can transfer the
heat to the air.
The use of aluminum cylinder blocks, cylinder
heads, and water pumps requires special corrosion
protection. MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769), or the equiva-
lent ethylene glycol base coolant with organic corro-
sion inhibitors (called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% Ethylene Glycol and 50% distilled
water to obtain a freeze point of -37ÉC (-35ÉF). If it
loses color or becomes contaminated, drain, flush,
and replace with fresh properly mixed coolant solu-
tion.
CAUTION: MoparTAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769) may not be
mixed with any other type of antifreeze. Mixing of
coolants other than specified (non-HOAT or other
HOAT), may result in engine damage that may not
be covered under the new vehicle warranty, and
decreased corrosion protection.
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water
mixture depends upon climate and vehicle operating
conditions. The coolant performance of various mix-
tures follows:
Pure Water-Water can absorb more heat than a
mixture of water and ethylene-glycol. This is for pur-
pose of heat transfer only. Water also freezes at a
higher temperature and allows corrosion.
100 percent Ethylene-Glycol-The corrosion
inhibiting additives in ethylene-glycol need the pres-
ence of water to dissolve. Without water, additives
form deposits in system. These act as insulation
causing temperature to rise to as high as 149ÉC
(300ÉF). This temperature is hot enough to melt plas-
tic and soften solder. The increased temperature can
result in engine detonation. In addition, 100 percent
ethylene-glycol freezes at -22ÉC (-8ÉF).
50/50 Ethylene-Glycol and Water-Is the recom-
mended mixture, it provides protection against freez-
ing to -37ÉC (-34ÉF). The antifreeze concentration
must alwaysbe a minimum of 44 percent, year-
round in all climates. If percentage is lower, engine
parts may be eroded by cavitation. Maximum protec-
tion against freezing is provided with a 68 percent
antifreeze concentration, which prevents freezing
down to -67.7ÉC (-90ÉF). A higher percentage will
freeze at a warmer temperature. Also, a higher per-
KJLUBRICATION & MAINTENANCE 0 - 3
FLUID TYPES (Continued)

centage of antifreeze can cause the engine to over-
heat because specific heat of antifreeze is lower than
that of water.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
CAUTION: Do not use coolant additives that are
claimed to improve engine cooling.
OPERATION - AUTOMATIC TRANSMISSION
FLUID
The automatic transmission fluid is selected based
upon several qualities. The fluid must provide a high
level of protection for the internal components by
providing a lubricating film between adjacent metal
components. The fluid must also be thermally stable
so that it can maintain a consistent viscosity through
a large temperature range. If the viscosity stays con-
stant through the temperature range of operation,
transmission operation and shift feel will remain con-
sistent. Transmission fluid must also be a good con-
ductor of heat. The fluid must absorb heat from the
internal transmission components and transfer that
heat to the transmission case.
FLUID CAPACITIES
SPECIFICATIONS - FLUID CAPACITIES
DESCRIPTION SPECIFICATION
FUEL TANK 18.5 U.S. Gallons (70
Liters)****
ENGINE OIL
Engine Oil - with Filter -
2.4L2.4L (5.0 qts.)
Engine Oil - with Filter -
3.7L3.7L (5.0 qts.)
Engine Oil - With Filter -
2.5L Diesel6.5L (6.9 qts.)
ENGINE COOLANT
Cooling System - 2.4L 9.6L (10.1 qts.)
Cooling System - 3.7L 12.3L (13.0 qts.)
Cooling System - 2.5L
Diesel12.5L (13.2 qts.)
AUTOMATIC TRANSMISSION
Service Fill - 45RFE 4.73L (10.0 pts)
O-haul Fill - 45RFE 13.33L (28.0 pts)
Dry fill capacity Depending on type and size of
internal cooler, length and inside diameter of cooler
lines, or use of an auxiliary cooler, these figures may
vary. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC/FLUID - STANDARD PROCEDURE)
TRANSFER CASE
NV231 1.4L (2.95 pts.)
NV242 1.6L (3.4 pts.)
MANUAL TRANSMISSION
NV1500 (Approximate dry
fill or fill to bottom edge of
the fill plug hole.)2.28L (2.41 qts.)
NV3550 (Approximate dry
fill or fill to bottom edge of
fill plug hole.)2.28L (2.41 qts.)
FRONT AXLE
186 FIA (Model 30) 1.24L (41.9 fl. oz.)
REAR AXLE
198 RBI (Model 35) 1.78L (60.2 fl. oz.)*
8 1/4 2.08L (4.4 pts.)*
* When equipped with Trac-lok, include 4.0 ounces of
Friction Modifier.
****Nominal refill capacities are shown. A variation
may be observed from vehicle to vehicle due to
manufacturing tolerance and refill procedure.
0 - 4 LUBRICATION & MAINTENANCEKJ
FLUID TYPES (Continued)

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 3.7L
ENGINE..............................1
DESCRIPTION - COOLING SYSTEM
ROUTING 3.7L ENGINE..................2
DESCRIPTION - HOSE CLAMPS...........2
OPERATION
OPERATION - COOLING SYSTEM.........2
OPERATION - HOSE CLAMPS............3
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTICS (OBD)...................3
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS.............................3
DIAGNOSIS AND TESTING - COOLING
SYSTEM LEAKS.......................4DIAGNOSIS AND TESTING - COOLING
SYSTEM DIAGNOSIS CHART.............6
STANDARD PROCEDURE
STANDARD PROCEDURE - DRAINING
COOLING SYSTEM 3.7L ENGINE.........12
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 3.7L ENGINE.........12
STANDARD PROCEDURE - COOLING
SYSTEM - REVERSE FLUSHING..........12
SPECIFICATIONS
TORQUE............................13
SPECIAL TOOLS
COOLING...........................14
ACCESSORY DRIVE......................15
ENGINE...............................19
TRANSMISSION.........................32
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM 3.7L
ENGINE
The cooling system consists of the following items:
²Electric cooling fan - Standard.
²Electric cooling fan and mechanical thermal vis-
cous fan with low disengaged - Heavy duty cooling
only²Radiator
²Hot bottle pressure cap
²Thermostat
²Coolant reserve/overflow system
²Radiator in-tank transmission oil cooler (if
equipped with an automatic transmission)
²Coolant
²Water pump
²Hoses and hose clamps
KJCOOLING 7 - 1

DESCRIPTION - COOLING SYSTEM ROUTING
3.7L ENGINE
For cooling system routing refer to (Fig. 1).
DESCRIPTION - HOSE CLAMPS
The cooling system utilizes spring type hose
clamps. If a spring type clamp replacement is neces-
sary, replace with the original Mopartequipment
spring type clamp.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094) (Fig. 2). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS.ALWAYS WEAR SAFETY GLASSES WHEN SERVIC-
ING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only a original equipment clamp
with matching number or letter (Fig. 2).
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.
Fig. 1 Engine Cooling System 3.7L Engine
1 - LH CYL. HEAD
2 - AIR BLEED
3 - THERMOSTAT LOCATION
4 - RH CYL. HEAD5 - RH BANK CYL. BLOCK
6 - LH BANK CYL. BLOCK
7 - COOLANT TEMP. SENSOR
7 - 2 COOLINGKJ
COOLING (Continued)

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.
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 TESTING - ON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
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 relay circuit controlling the electric radiator fan,
a Diagnostic Trouble Code (DTC) can be set.
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 PCM 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 DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
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
²STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
(1) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(2) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect 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).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
Fig. 2 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
KJCOOLING 7 - 3
COOLING (Continued)

DIAGNOSIS AND TESTING - COOLING SYSTEM
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 engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
checked. If leaks are present, black light will cause
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. 3).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove radiator pressure cap from pres-
sure bottle and check coolant level. Push down on
cap to disengage it from stop tabs. Wipe inside of
filler neck and examine lower inside sealing seat fornicks, cracks, paint, and dirt. Inspect radiator-to-
reserve/overflow tank hose for internal obstructions.
Insert a wire through the hose to be sure it is not
obstructed.
Inspect cams on outside of filler neck. If cams are
damaged, seating of pressure cap valve and tester
seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck (Fig. 4).
Operate tester pump to apply 110 kPa (16 psi)
pressure to system. If hoses enlarge excessively or
bulges while testing, replace as necessary. Observe
gauge pointer and determine condition of cooling sys-
tem according to following criteria:
Holds Steady:If pointer remains steady for two
minutes, serious coolant leaks are not present in sys-
tem. However, there could be an internal leak that
does not appear with normal system test pressure. If
it is certain that coolant is being lost and leaks can-
not be detected, inspect for interior leakage or per-
form Internal Leakage Test.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect radiator,
hoses, gasket edges and heater. Seal small leak holes
with a Sealer Lubricant (or equivalent). Repair leak
holes and inspect system again with pressure
applied.
Drops Quickly:Indicates that serious leakage is
occurring. Examine system for external leakage. If
leaks are not visible, inspect for internal leakage.
Large radiator leak holes should be repaired by a
reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
Fig. 3 Leak Detection Using Black Light - Typical
1 - TYPICAL BLACK LIGHT TOOL
Fig. 4 Pressure Testing Cooling System - Typical
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER
7 - 4 COOLINGKJ
COOLING (Continued)

the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 124 KPA (18 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.
If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
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 solution is
clean, drain 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/ENGINE
COOLANT 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 top of 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.
KJCOOLING 7 - 5
COOLING (Continued)

DIAGNOSIS AND TESTING - COOLING SYSTEM DIAGNOSIS CHART
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 (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 7 - COOLING/
ENGINE/ENGINE COOLANT TEMP
SENSOR - DESCRIPTION). Repair
connector if necessary.
3. Is the temperature gauge
operating OK?3. Check gauge operation. Repair
as necessary.
4. Coolant level low in cold ambient
temperatures accompanied with
poor heater performance.4. Check coolant level in the coolant
pressure botttle and the radiator.
Inspect system for leaks. Repair
leaks as necessary.
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)
6. Electric fan functioning when not
required.6. Inspect electric fan for proper
operation. Refer to Electric Cooling
Fan in this section. Refer to group
8W for electric cooling fan and relay
circuit schematic data.
1. 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.
2. Is the temperature gauge reading
correctly?2. Check gauge. (Refer to Group 8J
- INSTRUMENT CLUSTER). Repair
as necessary.
3. Is the temperature warning
illuminating unnecessarily?3. Check warning lamp operation.
(Refer to Group 8J - INSTRUMENT
CLUSTER).Repair as necessary.
4. Coolant low in coolant pressure
bottle and radiator?4. Check for coolant leaks and
repair as necessary. (Refer to 7 -
COOLING - DIAGNOSIS AND
TESTING).
7 - 6 COOLINGKJ
COOLING (Continued)