2003 GMC YUKON heating

Engine Coolant
The cooling system in your vehicle isfilled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occursfirst, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, seeEngine Overheating on
page 5-29.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
•Give freezing protection down to−34°F(−37°C).
•Give boiling protection up to 265°F (129°C).
•Protect against rust and corrosion.
•Help keep the proper engine temperature.
•Let the warning lights and gages work as they
should.Notice:When adding coolant, it is important that
you use only DEX-COOL
®(silicate-free) coolant.
If coolant other than DEX-COOL®is added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the engine
coolant will require change sooner—at 30,000 miles
(50,000 km) or 24 months, whichever occursrst.
Damage caused by the use of coolant other
than DEX-COOL
®is not covered by your new vehicle
warranty.
What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOL®coolant which won’t damage
aluminum parts. If you use this coolant mixture,
you don’t need to add anything else.
5-26
2003 - Yukon/Yukon XL

Coolant Surge Tank Pressure Cap
SeeEngine Compartment
Overview on page 5-12for
more information on
location.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank.
Notice:Your pressure cap is a pressure-type cap
and must be tightly installed to prevent coolant loss
and possible engine damage from overheating.
See“Capacities and Specications”for more
information.
Engine Overheating
You willfind a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-46. In addition, you will
find a LOW COOLANT LEVEL, ENGINE OVERHEATED
and a REDUCED ENGINE POWER message in the
DIC on the instrument panel. SeeDriver Information
Center (DIC) on page 3-53.
Overheated Engine Protection
Operating Mode (V8 Engines Only)
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternatesfiring
groups of cylinders helps prevent engine damage. In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. See“Engine Oil”in the Index.
5-29
2003 - Yukon/Yukon XL

Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service,
see your GMC Warranty booklet for details.{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See“Loading Your
Vehicle”in the Index.
Underinated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
Overinated tires are more likely to be
cut, punctured or broken by a sudden
impact—such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents. If
your tread is badly worn, or if your tires
have been damaged, replace them.
5-60
2003 - Yukon/Yukon XL

Cooling System Capacity
ApplicationCapacities
English Metric
Cooling System
VORTEC™4800 V8 Automatic with front A/C 14.4 quarts 13.6 L
VORTEC™4800 V8 Automatic with front and rear A/C 15.8 quarts 15.0 L
VORTEC™5300 V8 Automatic with front A/C 14.4 quarts 13.6 L
VORTEC™5300 V8* Automatic with front and rear A/C 15.8 quarts 15.0 L
VORTEC™6000 V8 Automatic 15.8 quarts 15.0 L
VORTEC™6000 V8** Automatic with engine oil cooler 15.4 quarts 14.6 L
VORTEC™8100 V8 Automatic 20.7 quarts 19.6 L
*Vehicles equipped with the optional air conditioner.
**Vehicles equipped with the optional engine oil cooler.
Add one liter if equipped with rear heating for all engines.
After refill, the level must be rechecked. Add enough engine oil so that thefluid is within the proper operating range.
SeeEngine Oil on page 5-16.
5-107
2003 - Yukon/Yukon XL

Cleaning (cont.)
Underbody Maintenance...............................5-94
Video Screen............................................3-125
Weatherstrips..............................................5-91
Cleaning Aluminum or Chrome-Plated Wheels.....5-93
Cleaning Exterior Lamps/Lenses.......................5-92
Cleaning Fabric/Carpet....................................5-89
Cleaning Glass Surfaces..................................5-91
Cleaning Interior Plastic Components.................5-91
Cleaning Leather............................................5-90
Cleaning the Mirror.........................................2-43
Cleaning the Top of the Instrument Panel...........5-91
Cleaning the Windshield, Backglass and Wiper
Blades.......................................................5-93
Cleaning Tires................................................5-94
Cleaning Vinyl................................................5-90
Climate Control System...................................3-21
Dual ..........................................................3-22
Dual Automatic............................................3-26
Rear Air Conditioning and Heating System......3-33
Rear Air Conditioning and Heating System,
Electronic................................................3-35
Rear Air Conditioning System........................3-32
Compact Disc Messages................3-84, 3-97, 3-110
Compass Calibration...............................2-42, 2-44
Compass Operation.........................................2-44
Compass Variance..................................2-41, 2-44Content Theft-Deferrent....................................2-16
Control of a Vehicle.......................................... 4-6
Convenience Net............................................2-56
Coolant
Engine Temperature Gage............................3-46
Heater, Engine............................................2-21
Surge Tank Pressure Cap.............................5-29
Cooling System..............................................5-32
Cruise Control................................................3-11
Cruise Control Light........................................3-52
Cupholder(s)..................................................2-54
Current and Past Model Order Forms................7-11
Customer Assistance Information
Courtesy Transportation.................................. 7-7
Customer Assistance for Text Telephone (TTY)
Users....................................................... 7-4
Customer Assistance Offices........................... 7-4
Customer Satisfaction Procedure..................... 7-2
GM Mobility Program for Persons with
Disabilities................................................ 7-5
Reporting Safety Defects to General Motors....7-10
Reporting Safety Defects to the Canadian
Government............................................7-10
Reporting Safety Defects to the United States
Government.............................................. 7-9
Roadside Assistance Program......................... 7-5
Service Publications Ordering Information........7-10
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2003 - Yukon/Yukon XL

E
Easy Exit Seat...............................................2-60
Electrical System
Add-On Equipment......................................5-97
Fuses and Circuit Breakers...........................5-98
Power Windows and Other Power Options......5-97
Windshield Wiper Fuses...............................5-97
Electrochromic Mirror Operation................2-41, 2-43
Emissions Inspection and Maintenance
Programs...................................................3-50
Engine
Air Cleaner/Filter.........................................5-21
Battery.......................................................5-43
Check and Service Engine Soon Light............3-48
Compartment Overview................................5-12
Coolant......................................................5-26
Coolant Heater............................................2-21
Coolant Temperature Gage...........................3-46
Cooling System Inspection............................6-16
Exhaust.....................................................2-38
Fan Noise..................................................5-37
Oil .............................................................5-16
Overheating................................................5-29
Starting
......................................................2-20
ENGINE COOLANT HOT
.................................3-64
Engine Coolant Level Check
.............................6-11
Engine Hour Meter Display
...............................3-39Engine Oil Additives........................................5-19
Engine Oil Level Check...................................6-11
ENGINE OVERHEATED..................................3-65
Entering or Exiting the Third Row Seats.............. 1-8
Entertainment System
Cleaning the Video Screen..........................3-125
DVD Distortion..........................................3-123
Entry Lighting.................................................3-18
Environmental Concerns..................................4-26
Erasing HomeLink
®Buttons..............................2-53
Exit Lighting...................................................3-18
Express-Down Windows...................................2-15
Extender, Safety Belt.......................................1-43
Exterior Lamps...............................................3-14
F
Filter
Engine Air Cleaner......................................5-21
Finding a PTY Station
(RDS and XM™) .......................3-78, 3-88, 3-101
Finding a Station....................3-73, 3-76, 3-86, 3-99
Finish Care....................................................5-92
Finish Damage...............................................5-94
Fixed Mast Antenna.......................................3-125
Flash-To-Pass.................................................. 3-9
Flat Tire........................................................5-69
Flat Tire, Changing.........................................5-69
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2003 - Yukon/Yukon XL

H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-8
Headlamp High/Low-Beam Changer.................... 3-9
Headlamps....................................................5-53
Bulb Replacement.......................................5-52
Front Turn Signal, Sidemarker and Daytime
Running Lamps........................................5-54
Halogen Bulbs............................................5-53
Roof Marker Lamps.....................................5-55
Side Identification Marker Lamps...................5-55
Headphones.................................................3-117
Heated Seats................................................... 1-5
Heating.........................................................3-30
Highway Hypnosis...........................................4-44
Hill and Mountain Roads..................................4-45
Hitches..........................................................4-67
HomeLink Transmitter, Programming..................2-51
HomeLink
®Transmitter....................................2-50
Hood
Checking Things Under................................5-10
Release.....................................................5-11
Horn ............................................................... 3-7
How to Add Coolant to the Coolant Surge Tank......5-34
How to Add Fluid
............................................5-25
How to Check
........................................5-23, 5-61
How to Check Lubricant
...................................5-50How to Check Power Steering Fluid..................5-39
How to Inspect...............................................5-21
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-27
Hydroplaning..................................................4-40
I
If No Steam Is Coming From Your Engine..........5-31
If Steam Is Coming From Your Engine...............5-30
If the Light is Flashing.....................................3-49
If the Light Is On Steady.................................3-49
If You Are Stuck in Sand, Mud, Ice or Snow.......4-52
If You Do Decide To Pull A Trailer.....................4-62
If You’re Caught in a Blizzard...........................4-50
Ignition Positions.............................................2-19
Ignition Transmission Lock Check......................6-14
Infants and Young Children, Restraints...............1-46
Inflation -- Tire Pressure..................................5-61
Inspection
Brake System.............................................6-16
Engine Cooling System................................6-16
Exhaust System..........................................6-15
Fuel System...............................................6-15
Part C - Periodic Maintenance.......................6-15
Steering and Suspension..............................6-15
Transfer Case and Front Axle
(Four-Wheel Drive)...................................6-16
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2003 - Yukon/Yukon XL

Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-11
Part C - Periodic Maintenance Inspections..........6-15
PartD-Recommended Fluids and Lubricants....6-17
PartE-Maintenance Record...........................6-19
Passenger Air Bag Indicator.....................2-43, 2-45
Passenger Air Bag Status Indicator...................3-40
PASSENGER DOOR AJAR..............................3-69
Passenger Sensing System..............................1-81
Passing.................................................4-20, 4-69
Passlock
®......................................................2-18
Personalization Button.....................................3-57
Plan Ahead When Possible................................ 7-7
Playing a Cassette Tape..................................3-93
Playing a Compact Disc.................3-83, 3-95, 3-106
Playing a Specific Loaded
Compact Disc............................................3-107
Playing the Radio...................3-72, 3-76, 3-86, 3-99
Power
Accessory Outlets........................................3-20
Door Locks.................................................. 2-8
Electrical System.........................................5-97
Lumbar Controls........................................... 1-5
Seat ............................................................ 1-4
Steering Fluid.............................................5-38
Windows
....................................................2-15
Power Steering
...............................................4-14
Power Winches
..............................................4-74
Programmable Automatic Door Locks
.................. 2-9
Programming the HomeLink Transmitter
.............2-51
Q
QUADRASTEER™..........................................4-16
Questions and Answers About Safety Belts.........1-27
R
Radio Data System (RDS)...............3-75, 3-85, 3-98
Radio Messages.............................3-74, 3-80, 3-90
Radios..........................................................3-71
AM-FM Radio.............................................3-72
Care of Your Cassette Tape Player...............3-124
Care of Your CD and DVD Player................3-125
Care of Your CDs and DVDs .......................3-125
Radio with Cassette and CD.........................3-85
Radio with CD............................................3-75
Radio with Six-Disc CD................................3-98
Rear Seat Audio........................................3-120
Setting the Time for Radios with Radio Data
Systems (RDS)........................................3-72
Setting the Time for Radios without Radio
Data Systems (RDS)................................3-71
Theft-Deterrent..........................................3-122
Understanding Reception............................3-123
RDS Messages.............................3-79, 3-89, 3-103
REAR ACCESS OPEN ....................................3-67
Rear Air Conditioning and Heating System.........3-33
Rear Air Conditioning and Heating System and
Electronic Climate Controls...........................3-35
Rear Air Conditioning System...........................3-32
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2003 - Yukon/Yukon XL