2003 GMC YUKON engine overheat

The coolant level should
be at or above the FULL
COLD mark. If it isn’t,
you may have a leak at the
pressure cap or in the
radiator hoses, heater
hoses, radiator, water
pump or somewhere else
in the cooling system.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don’t touch them. If you
do, you can be burned.
Don’t run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an enginere, and you could be
burned. Get any leakxed before you drive the
vehicle.If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal
down. If it doesn’t, your vehicle needs service. Turn off
the engine.
Notice:Engine damage from running your engine
without coolant isn’t covered by your warranty.
See“Overheated Engine Protection Operating
Mode”in the Index for information on driving to a
safe place in an emergency.
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.
5-33
2003 - Yukon/Yukon XL

{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle’s coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you wouldn’t get the overheat warning.
Your engine could catchre and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Don’t spill coolant on a hot engine.
1. Park the vehicle on a
level surface. You can
remove the coolant
surge tank pressure
cap when the cooling
system, including
the coolant surge tank
pressure cap and
upper radiator hose, is
no longer hot.
2. Turn the pressure cap slowly counterclockwise (left)
about one full turn. If you hear a hiss, wait for that to
stop. A hiss means there is still some pressure left.
3. Then keep turning the pressure cap slowly, and
remove it.
5-35
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
6
2003 - Yukon/Yukon XL

Mirrors (cont.)
Outside Manual Mirrors................................2-45
Outside Power Camper-Type.........................2-47
Outside Power Foldaway Mirrors....................2-47
Outside Power Mirrors..................................2-46
Model Reference................................................ vi
MyGMLink.com................................................ 7-3
N
New Vehicle Break-In......................................2-18
Normal Maintenance Replacement Parts...........5-109
O
Odometer......................................................3-39
Off-Road Recovery..........................................4-19
Oil
Engine.......................................................5-16
Pressure Gage............................................3-51
OIL PRESSURE LOW .....................................3-65
Older Children, Restraints................................1-44
Online Owner Center........................................ 7-3
OnStar
®Personal Calling.................................2-49
OnStar®Services............................................2-49
OnStar®Steering Wheel Controls......................2-50
OnStar®System.............................................2-48
OnStar®Virtual Advisor....................................2-49
Operating Your All-Wheel-Drive Vehicle Off
Paved Roads..............................................4-22Other Warning Devices...................................... 3-7
Outlet Adjustment...................................3-25, 3-31
Outside
Automatic Dimming Mirror.............................2-47
Camper-Type Mirrors....................................2-46
Convex Mirror.............................................2-48
Curb View Assist Mirrors..............................2-47
Heated Mirrors............................................2-48
Manual Mirrors............................................2-45
Power Foldaway Mirrors...............................2-47
Power Mirrors.............................................2-46
Outside Power Camper-Type Mirror...................2-47
Overheated Engine Protection Operating Mode
(V8 Engines Only).......................................5-29
Owners, Canadian............................................... ii
Owner’s Information........................................7-11
P
Panel Doors...................................................2-13
Park (P)
Shifting Out of............................................2-37
Parking
Brake........................................................2-34
Over Things That Burn.................................2-38
Parking Brake and Automatic Transmission Park
(P) Mechanism Check..................................6-14
Parking on Hills..............................................4-71
Park(P)
Shifting Into................................................2-35
11
2003 - Yukon/Yukon XL