
COOLING SYSTEM
CONTENTS
page page
GENERAL INFORMATION
COOLANT PRESSURE BOTTLE............ 1
COOLING SYSTEM Ð 2.0L GASOLINE...... 1
COOLING SYSTEM Ð 2.5L VM DIESEL..... 1
LOW COOLANT LEVEL SENSOR........... 1
RADIATOR............................ 2
DESCRIPTION AND OPERATION
AUTOMATIC BELT TENSIONER............ 6
BELT TENSION......................... 5
COOLANT PERFORMANCE............... 5
PRESSURE/VENT CAP................... 4
THERMOSTAT OPERATION............... 4
THERMOSTAT......................... 6
WATER PUMP......................... 3
SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT........... 7
DRAINING COOLING SYSTEM............. 7
REFILLING COOLING SYSTEM............ 7
REMOVAL AND INSTALLATION
ENGINE THERMOSTATÐ 2.0L GASOLINE . . . 9GENERATOR/POWER STEERING BELT Ð 2.5L
VM DIESEL......................... 10
RADIATOR Ð 2.5L VM DIESEL........... 9
THERMOSTAT Ð 2.5L VM DIESEL......... 9
WATER PUMP BELT Ð 2.5L VM DIESEL . . . 10
WATER PUMP Ð 2.0L GASOLINE......... 7
WATER PUMP Ð 2.5L VM DIESEL........ 8
CLEANING AND INSPECTION
WATER PUMP........................ 10
ADJUSTMENTS
BELT TENSION CHART................. 11
BELT TENSION GAUGE METHOD......... 11
SPECIFICATIONS
COOLING SYSTEM CAPACITY............ 12
TORQUE CHART...................... 12
SPECIAL TOOLS
COOLING............................ 12
GENERAL INFORMATION
COOLING SYSTEM Ð 2.0L GASOLINE
The 2.0L gasoline engine cooling system consists of
an engine cooling module, thermostat, coolant, a
water pump to circulate the coolant. The engine cool-
ing module may consist of a radiator, electric fan
motors, fan, shroud, coolant reserve system, hoses,
clamps, air condition condenser.
²When the Engine is cold: The thermostat is
closed; the cooling system has no flow through the
radiator. The coolant flows through the engine,
heater system and bypass.
²When the Engine is warm: Thermostat is open;
the cooling system has flow through radiator, engine,
heater system and bypass.
COOLING SYSTEM Ð 2.5L VM DIESEL
The cooling system has a radiator, coolant, electric
fan motors, shroud, pressure cap, thermostat, coolant
pressure bottle, hoses, a water pump to circulate the
coolant, to complete the circuit. Coolant flow for the
VM diesel engine is shown in (Fig. 1).
COOLANT PRESSURE BOTTLE
2.5L VM DIESEL
This system works with the pressure cap to use
thermal expansion and contraction of the coolant to
keep the coolant free of trapped air. It provides some
reserve coolant to cover minor leaks and evaporation
or boiling losses. The coolant pressure bottle location
for 2.5L diesel is above the cylinder head cover (Fig.
2).
LOW COOLANT LEVEL SENSOR
The low coolant level sensor checks for low coolant
level in the coolant tank. A signal will be sent from
this sensor to the Body Control Module (BCM). When
the BCM determines low coolant level for 30 contin-
uous seconds, the instrument panel mounted low
coolant level warning lamp will be illuminated. The
sensor is located on the front side of the coolant tank
(Fig. 4). For information, refer to Group 8E, Instru-
ment Panel and Gauges.
If this lamp is illuminated, it indicates the need to
fill the coolant tank and check for leaks.
NS/GSCOOLING SYSTEM 7 - 1

Initial belt adjustment is done with a adjustable
tensioner pulley. After the initial adjustment is per-
formed, an automatic belt tensioner is used to main-
tain correct belt tension at all times. Do not attempt
to check belt tension with a belt tension gauge on
vehicles equipped with an automatic belt tensioner.
Refer to Automatic Belt Tensioner in this group.
AUTOMATIC BELT TENSIONER
Drive belt tension is controlled by a spring loaded
automatic belt tensioner located below and to the
front of the engine oil filter (Fig. 12). This tensioner
is connected to a pivot bracket and a pulley (Fig. 12).
The pivot bracket rotates on a pivot pin attached to
the engine. Special machined washers with rubber
o-rings (Fig. 12) are used at each side of the pivot
bracket to help keep dirt and water away from the
pivot pin.
If a defective belt tensioner is suspected, a check of
this pivot bracket and pivot pin should be made. Cor-
rosion may have formed at the pin and may cause
the pivot bracket to stick. Belt slippage will result.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE THE
AUTOMATIC BELT TENSIONER. UNIT IS SERVICED
AS AN ASSEMBLY.
THERMOSTAT
DIAGNOSIS
Diesel engines, due to their inherent efficiency are
slower to warm up than gasoline powered engines,
and will operate at lower temperatures when the
vehicle is unloaded. Because of this, lower tempera-
ture gauge readings for diesel versus gasoline
engines may, at times be normal.
Typically, complaints of low engine coolant temper-
ature are observed as low heater output when com-
bined with cool or cold outside temperatures.
To help promote faster engine warm-up, an electric
engine block heater must be used with cool or cold
outside temperatures. This will help keep the engine
coolant warm when the vehicle is parked. Use the
block heater if the outside temperature is below 4ÉC
(40ÉF).Do not use the block heater if the out-
side temperature is above 4ÉC (40ÉF).
TESTING
NOTE: The DRB scan tool shoud be used to moni-
tor engine coolant temperature on the diesel
engine. Refer to the 1998 GS Powertrain Diagnostic
Manual for thermostat diagnosis procedure.
Fig. 12 Automatic Belt Tensioner Assembly
7 - 6 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)

SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT
2.5L VM DIESEL
Do not remove coolant bottle pressure cap when
the engine is hot. Remove pressure cap and fill cool-
ant bottle between Min and Max lines inside filler
neck. Use only 50/50 mix of ethylene glycol type anti-
freeze and water (Fig. 13). Squeezing radiator hoses
may help purge air from the cooling system.
DRAINING COOLING SYSTEM
2.0L GASOLINE
To drain cooling system move temperature selector
for heater to full heat with engine running.Without
removing radiator pressure cap and with sys-
tem not under pressure,Shut engine off and open
draincock. The coolant reserve tank should empty
first, then remove radiator pressure cap and let the
radiator drain (if not, see Testing Cooling System for
leaks).
2.5L VM DIESEL
The cooling system does not have a radiator
mounted pressure cap. Instead the pressure cap is
mounted on the coolant pressure bottle (Fig. 14).
(1) Shut off engine.
(2) Remove radiator pressure cap.
(3) Open draincock and allow coolant to drain.
REFILLING COOLING SYSTEM
2.0L GASOLINE
Refer to the gasoline engine cooling system infor-
mation in this manual. Cooling system capacity is 6.0
liters (6.34 qts.) which includes the heater and cool-
ant recovery tank.
2.5L VM DIESEL
First clean system to remove old glycol, see Cooling
System Cleaning.
(1) Disconnect upper radiator hose at thermostat
housing.
(2) Remove pressure cap from coolant expansion
tank.
(3) Fill cooling system through upper radiator hose
until coolant starts to leak out at the thermostat
housing. Reconnect hose and re-install clamp.
(4) Fill expansion tank to top of bottle. Run engine
at idle without pressure cap installed for 5 minutes.
Squeeze upper radiator hose several times.
(5) Shut off engine. Top off coolant and install
pressure cap.
(6) Inspect system for leaks.
REMOVAL AND INSTALLATION
WATER PUMP Ð 2.0L GASOLINE
REMOVAL
(1) Remove accessory drive belts and power steer-
ing pump.
(2) Drain cooling system.
Fig. 13 Coolant Pressure BottleÐ2.5L VM Diesel
Fig. 14 Pressure Cap and BottleÐVM Diesel
NS/GSCOOLING SYSTEM 7 - 7

BATTERY
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION......................... 1
SAFETY PRECAUTIONS AND WARNINGS..... 1
DESCRIPTION AND OPERATION
BATTERY IGNITION OFF DRAW (IOD)........ 1
CHARGING TIME REQUIRED............... 2
DIAGNOSIS AND TESTING
BATTERY BUILT-IN TEST INDICATOR........ 2
BATTERY IGNITION OFF DRAW (IOD)........ 3
BATTERY LOAD TEST..................... 4
BATTERY OPEN CIRCUIT VOLTAGE TEST..... 6SERVICE PROCEDURES
BATTERY CHARGING..................... 6
CHARGING COMPLETELY DISCHARGED
BATTERY............................. 7
VISUAL INSPECTION..................... 7
REMOVAL AND INSTALLATION
BATTERY TRAY.......................... 9
BATTERY............................... 8
SPECIFICATIONS
BATTERY SPECIFICATIONS............... 10
TORQUE.............................. 10
GENERAL INFORMATION
INTRODUCTION
The battery stores, stabilizes, and delivers electri-
cal current to operate various electrical systems in
the vehicle. The determination of whether a battery
is good or bad is made by its ability to accept a
charge. It also must supply high-amperage current
for a long enough period to be able to start the vehi-
cle. The capability of the battery to store electrical
current comes from a chemical reaction. This reac-
tion takes place between the sulfuric acid solution
(electrolyte) and the lead +/- plates in each cell of the
battery. As the battery discharges, the plates react
with the acid from the electrolyte. When the charging
system charges the battery, the water is converted to
sulfuric acid in the battery. The concentration of acid
in the electrolyte is measured as specific gravity
using a hydrometer. The original equipment (OE)
battery is equipped with a hydrometer (test indica-
tor) built into the battery cover. The specific gravity
indicates the battery's state-of-charge. The OE bat-
tery is sealed and water cannot be added.
The battery is vented to release gases that are cre-
ated when the battery is being charged and dis-
charged. The battery top, posts, and terminals should
be cleaned when other under hood maintenance is
performed.
When the electrolyte level is below the top of the
plates, Clear in the test Indicator, the battery must
be replaced. The battery must be completely charged,
and the battery top, posts, and cable clamps must be
cleaned before diagnostic procedures are performed.
SAFETY PRECAUTIONS AND WARNINGS
WARNING: DO NOT ALLOW JUMPER CABLE
CLAMPS TO TOUCH EACH OTHER WHEN CON-
NECTED TO A BOOSTER SOURCE. DO NOT USE
OPEN FLAME NEAR BATTERY. REMOVE METALLIC
JEWELRY WORN ON HANDS OR WRISTS TO AVOID
INJURY BY ACCIDENTAL ARCING OF BATTERY
CURRENT.
WHEN USING A HIGH OUTPUT BOOSTING DEVICE,
DO NOT ALLOW THE DISABLED VEHICLE'S BAT-
TERY TO EXCEED 16 VOLTS. PERSONAL INJURY
OR DAMAGE TO ELECTRICAL SYSTEM CAN
RESULT.
TO PROTECT THE HANDS FROM BATTERY ACID, A
SUITABLE PAIR OF HEAVY DUTY RUBBER
GLOVES, NOT THE HOUSEHOLD TYPE, SHOULD
BE WORN WHEN REMOVING OR SERVICING A
BATTERY. SAFETY GLASSES ALSO SHOULD BE
WORN.
DESCRIPTION AND OPERATION
BATTERY IGNITION OFF DRAW (IOD)
A completely normal vehicle will have a small
amount of current drain on the battery with the key
out of the ignition. It can range from 5 to 25 milli-
amperes after all the modules time out. If a vehicle
will not be operated for approximately a 20 days, the
IOD fuse should be pulled to eliminate the vehicle
electrical drain on the battery. The IOD fuse is
NSBATTERY 8A - 1

use. Refer to Causes of Battery Discharging in this
Group for more information.
NOTE: CLEAR COLOR = Replace Battery
WARNING: DO NOT CHARGE, ASSIST BOOST,
LOAD TEST, OR ADD WATER TO THE BATTERY
WHEN CLEAR COLOR DOT IS VISIBLE. PERSONAL
INJURY MAY OCCUR.
A clear color dot shows electrolyte level in battery
is below the test indicator (Fig. 1). Water cannot be
added to a maintenance free battery. The battery
must be replaced. A low electrolyte level may be
caused by an over charging condition. Refer to Gen-
erator Test Procedures on Vehicle.
CAUSES OF BATTERY DISCHARGING
It is normal to have a small 5 to 25 milliamperes
continuous electrical draw from the battery. This
draw will take place with the ignition in the OFF
position, and the courtesy, dome, storage compart-
ments, and engine compartment lights OFF. The con-
tinuous draw is due to various electronic features or
accessories that require electrical current with the
ignition OFF to function properly. When a vehicle is
not used over an extended period of approximately 20
days the IOD fuse should be pulled. The fuse is
located in the power distribution center. Disconnec-
tion of this fuse will reduce the level of battery dis-
charge. Refer to Battery Diagnosis and Testing table
and to the proper procedures.
ABNORMAL BATTERY DISCHARGING
²Corroded battery posts, cables or terminals.
²Loose or worn generator drive belt.
²Electrical loads that exceed the output of the
charging system due to equipment or accessories
installed after delivery.
²Slow driving speeds in heavy traffic conditions
or prolonged idling with high-amperage electrical
systems in use.²Defective electrical circuit or component causing
excess Ignition Off Draw (IOD). Refer to Battery
Ignition Off Draw (IOD).
²Defective charging system.
²Defective battery.
BATTERY IGNITION OFF DRAW (IOD)
High current draw on the battery with the ignition
OFF will discharge a battery. After a dead battery is
serviced the vehicle Ignition Off Draw (IOD) should
be checked. Determine if a high current draw condi-
tion exists first check the vehicle with a test lamp.
(1) Verify that all electrical accessories are OFF.
²Remove key from ignition switch
²Turn off all lights
²Liftgate and glove box door is closed
²Sun visor vanity lights are OFF
²All doors are closed
²Allow the Illuminated Entry System to time out
in approximately 30 seconds, if equipped.
²During Transmission Control Module (TCM)
power down there will be 500 milliamperes present
for 20 minutes. Afterwards less than 1.0 milliampere.
(2) Disconnect battery negative cable (Fig. 4).
CAUTION: Always disconnect the meter before
opening a door.
(3) Using an multimeter, that has least a milliam-
pere range of 200 mA. Set meter to the highest mA
range. Install meter between the battery negative
cable and battery negative post (Fig. 5). Carefully
remove the test lamp without disconnecting the
meter. After all modules time-out the total vehicle
IOD should be less than 25 milliamperes. If ignition
off draw is more than 25 milliamperes go to Step 4.
(4) Each time the test lamp or milliampere meter
is disconnected and connected, all electronic timer
functions will be activated for approximately one
minute. The Body Control Module (BCM) ignition off
draw can reach 90 milliamperes.
(5) Remove the PDC fuses:
²Interior lamps
²Brake lamp
²IOD
(6) If there is any reading, with fuses removed
there is a short circuit in the wiring. Refer to Group
8W, wiring diagrams. If reading is less than 25 mA
go to Step 8.
(7) Install all fuses. After installing fuse, the cur-
rent can reach 90 mA. After time-out the reading
should not exceed 25 mA. If OK go to. If not, discon-
nect:
²Radio
²Body Control Module
²Remote Keyless Entry Module
Fig. 3 Test Indicator
NSBATTERY 8A - 3
DIAGNOSIS AND TESTING (Continued)

BATTERY OPEN CIRCUIT VOLTAGE TEST
An open circuit voltage no load test shows the
state of charge of a battery and whether it is ready
for a load test at 50 percent of the battery's cold
crank rating. Refer to Battery Load Test. If a battery
has open circuit voltage reading of 12.4 volts or
greater, and will not pass the load test, replace the
battery because it is defective. To test open circuit
voltage, perform the following operation.
(1) Remove both battery cables, negative cable
first. Battery top, cables and posts should be clean. If
green dot is not visible in indicator, charge the bat-
tery. Refer to Battery Charging Procedures.
(2) Connect a Volt/Ammeter/Load tester to the bat-
tery posts (Fig. 6). Rotate the load control knob of the
Carbon pile rheostat to apply a 300 amp load. Apply
this load for 15 seconds to remove the surface charge
from the battery, and return the control knob to off
(Fig. 7).
(3) Allow the battery to stabilize for 2 minutes,
and then verify the open circuit voltage (Fig. 9).
(4) This voltage reading will approximate the state
of charge of the battery. It will not reveal battery
cranking capacity. Refer to Battery Open Circuit
Voltage table.
SERVICE PROCEDURES
BATTERY CHARGING
WARNING: DO NOT CHARGE A BATTERY THAT
HAS EXCESSIVELY LOW ELECTROLYTE LEVEL.
BATTERY MAY SPARK INTERNALLY AND
EXPLODE. EXPLOSIVE GASES FORM OVER THE
BATTERY. DO NOT SMOKE, USE FLAME, OR CRE-
ATE SPARKS NEAR BATTERY. DO NOT ASSIST
BOOST OR CHARGE A FROZEN BATTERY. BAT-
TERY CASING MAY FRACTURE. BATTERY ACID IS
POISON, AND MAY CAUSE SEVERE BURNS. BAT-
TERIES CONTAIN SULFURIC ACID. AVOID CON-
TACT WITH SKIN, EYES, OR CLOTHING. IN THE
EVENT OF CONTACT, FLUSH WITH WATER AND
CALL PHYSICIAN IMMEDIATELY. KEEP OUT OF
REACH OF CHILDREN.
CAUTION: Disconnect the battery NEGATIVE cable
first. (Fig. 4) before charging battery to avoid dam-
age to electrical systems. Do not exceed 16.0 volts
while charging battery. Refer to the instructions
supplied with charging equipment
NOTE: The battery cannot be refilled with water, it
must be replaced.
A battery is considered fully charged when it will
meet all the following requirements.
²It has an open circuit voltage charge of at least
12.4 volts.
²It passes the 15 second load test, refer to the
Load Test Temperature chart.
²The built in test indicator dot is GREEN (Fig.
1).
Battery electrolyte will bubble inside of battery
case while being charged properly. If the electrolyte
boils violently, or is discharged from the vent holes
while charging, immediately reduce charging rate or
turn off charger. Evaluate battery condition. Battery
damage may occur if charging is excessive.
Some battery chargers are equipped with polarity
sensing devices to protect the charger or battery from
being damaged if improperly connected. If the bat-
tery state of charge is too low for the polarity sensor
to detect, the sensor must be bypassed for charger to
operate. Refer to operating instructions provided
with battery charger being used.
CAUTION: Charge battery until test indicator
appears green. Do not overcharge.
It may be necessary to jiggle the battery or vehicle
to bring the green dot in the test indicator into view.
Fig. 9 Testing Open Circuit Voltage
BATTERY OPEN CIRCUIT VOLTAGE
Open Circuit VoltsCharge Per-
centage
11.7 volts or less 0%
12.0 volts 25%
12.2 volts 50%
12.4 volts 75%
12.6 volts or more 100%
8A - 6 BATTERYNS
DIAGNOSIS AND TESTING (Continued)

After the battery has been charged to 12.4 volts or
greater, perform a load test to determine cranking
capacity. Refer to Battery Load Test in this Group. If
the battery passes the load test, return the battery to
use. If battery will not endure a load test, it must be
replaced. Properly clean and inspect battery hold
downs, tray, terminals, cables, posts, and top before
completing service.
CHARGING COMPLETELY DISCHARGED BATTERY
The following procedure should be used to recharge
a completely discharged battery. Unless procedure is
properly followed, a good battery may be needlessly
replaced. Refer to Battery Charging Rate table.
(1) Measure the voltage at battery posts with a
voltmeter accurate to 1/10 volt (Fig. 10). If below 10
volts, charge current will be low, and it could take
some time before it accepts a current in excess of a
few milliamperes. Such low current may not be
detectable on amp meters built into many chargers.
(2) Connect charger leads. Some chargers feature
polarity protection circuitry that prevents operation
unless charger is connected to battery posts correctly.
A completely discharged battery may not have
enough voltage to activate this circuitry. This may
happen even though the leads are connected properly.
(3) Battery chargers vary in the amount of voltage
and current they provide. For the time required for
the battery to accept measurable charger current at
various voltages, refer to Battery Charging Rate
table. If charge current is still not measurable after
charging times, the battery should be replaced. Ifcharge current is measurable during charging time,
the battery may be good, and charging should be
completed in the normal manner.
VISUAL INSPECTION
CAUTION: Do not allow baking soda solution to
enter vent holes, as damage to battery can result.
(1) Clean top of battery with a solution of warm
water and baking soda.
(2) Apply soda solution with a bristle brush and
allow to soak until acid deposits loosen (Fig. 11).
(3) Rinse soda solution from battery with clear
water and blot battery dry with paper toweling. Dis-
pose of toweling in a safe manner. Refer to the
WARNINGS on top of battery.
(4) Inspect battery case and cover for cracks, leak-
age or damaged hold down ledge. If battery is dam-
aged replace it.
(5) Inspect battery tray for damage caused by acid
from battery. If acid is present, clean area with bak-
ing soda solution.
(6) Clean battery posts with a battery post clean-
ing tool (Fig. 12).
(7) Clean battery cable clamps with a battery ter-
minal cleaning tool (Fig. 13). Replace cables that are
frayed or have broken clamps.
BATTERY CHARGING RATE
Voltage Hours
16.0 volts maximum up to 4 hours
14.0 to 15.9 volts up to 8 hours
13.9 volts or less up to 16 hours
Fig. 10 Voltmeter Accurate to 1/10 Volt (Connected)
Fig. 11 Cleaning Battery
NSBATTERY 8A - 7
SERVICE PROCEDURES (Continued)

REMOVAL AND INSTALLATION
BATTERY
WARNING: TO PROTECT THE HANDS FROM BAT-
TERY ACID, A SUITABLE PAIR OF HEAVY DUTY
RUBBER GLOVES, NOT THE HOUSEHOLD TYPE,
SHOULD BE WORN WHEN REMOVING OR SERVIC-ING A BATTERY. SAFETY GLASSES ALSO SHOULD
BE WORN.
REMOVAL
(1) Verify that the ignition switch and all accesso-
ries are OFF.
(2) Disconnect battery cable terminals from the
battery posts, negative first (Fig. 14).
(3) Remove battery heat shield (Fig. 15).
(4) Remove battery hold down (Fig. 16).
(5) Remove battery from vehicle (Fig. 17).
INSTALLATION
Inspect and clean battery and attaching compo-
nents before installation.
(1) Install battery in vehicle making sure that bat-
tery is properly positioned on battery tray.
(2) Install battery hold down.
Fig. 12 Cleaning Battery Post
Fig. 13 Cleaning Battery Cable Terminal
Fig. 14 Battery Cable Disconnected
Fig. 15 Battery Heat Shield
8A - 8 BATTERYNS
SERVICE PROCEDURES (Continued)