2005 GMC YUKON DENALI engine overheat

Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-37.
In addition, you will nd an ENGINE COOLANT HOT,
ENGINE OVERHEATED and a REDUCED ENGINE
POWER message in the Driver Information Center (DIC)
on the instrument panel. SeeDIC Warnings and
Messages on page 3-50.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood. Stay
away from the engine if you see or hear steam
coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
CAUTION: (Continued)
CAUTION: (Continued)
If you keep driving when your engine is
overheated, the liquids in it can catch re. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
SeeOverheated Engine Protection Operating
Mode on page 5-30for information on driving
to a safe place in an emergency.
Notice:If your engine catches re because you keep
driving with no coolant, your vehicle can be badly
damaged. The costly repairs would not be covered by
your warranty. SeeOverheated Engine Protection
Operating Mode on page 5-30for information on
driving to a safe place in an emergency.
5-28

If No Steam Is Coming From Your
Engine
An overheat warning, along with a low coolant condition,
can indicate a serious problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-52.
If you get the overheat warning with no sign of steam, try
this for a minute or so:
1. If your air conditioner is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
3. If you are in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving — DRIVE (D).If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam and your vehicle is
equipped with an engine-driven cooling fan, push down
the accelerator until the engine speed is about twice
as fast as normal idle speed for at least three minutes
while you are parked.
If there is still no sign of steam and your vehicle is
equipped with an electric engine cooling fan, idle the
engine for three minutes while you are parked.
If you still have the warning,turn off the engine and get
everyone out of the vehicleuntil it cools down. Also,
see “Overheated Engine Protection Operating Mode”
later in this section.
You may decide not to lift the hood but to get service
help right away.
5-29

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates ring
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. SeeEngine Oil on page 5-14.
Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Electric Engine Cooling Fan (If Equipped)
5-30

If there seems to be no leak and your vehicle is
equipped with an electric engine cooling fan, with the
engine on check to see if the cooling fan is running. If it
is not, your vehicle needs service. Turn off the engine.
If there seems to be no leak and your vehicle is
equipped with an engine-driven cooling fan, start the
engine again and see if the fan speed increases when
idle speed is doubled by pushing the accelerator
pedal down. If it does not, your vehicle needs service.
Turn off the engine.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
Overheated Engine Protection Operating Mode on
page 5-30for information on driving to a safe place
in an emergency.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
How to Add Coolant to the Coolant
Surge Tank
If you have not found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the coolant level is not at or above the FULL COLD
mark, add a 50/50 mixture ofclean, drinkable water
and DEX-COOL
®coolant at the coolant surge tank, but
be sure the cooling system, including the coolant
surge tank pressure cap, is cool before you do it. See
Engine Coolant on page 5-25for more information.
If no coolant is visible in the surge tank, add coolant
as follows:
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap — even a little — they can come
out at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have
to turn the pressure cap.
5-32

{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 would not get the overheat warning.
Your engine could catch re 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. Do not spill coolant on a hot engine.
1. 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.
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.
2. Then keep turning the pressure cap slowly, and
remove it.
5-33

Driving
At Night.....................................................4-29
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Freeway.....................................................4-34
Hill and Mountain Roads..............................4-36
In Rain and on Wet Roads...........................4-31
Recovery Hooks..........................................4-43
Rocking Your Vehicle to Get it Out.................4-42
Winter........................................................4-38
Dual Automatic Climate Control System.............3-20
DVD
Rear Seat Entertainment System...................3-83
E
Electrical System
Add-On Equipment.....................................5-105
Center Instrument Panel Fuse Block.............5-108
Fuses and Circuit Breakers.........................5-105
Instrument Panel Fuse Block.......................5-106
Power Windows and Other Power Options....5-105
Underhood Fuse Block...............................5-109
Windshield Wiper Fuses.............................5-105
Engine
Air Cleaner/Filter.........................................5-19
Battery.......................................................5-41Engine (cont.)
Check and Service Engine Soon Light............3-39
Coolant......................................................5-25
Coolant Heater............................................2-22
Coolant Temperature Gage...........................3-37
Engine Compartment Overview......................5-12
Exhaust.....................................................2-30
Fan Noise..................................................5-35
Oil .............................................................5-14
Overheated Protection Operating Mode...........5-30
Overheating................................................5-28
Starting......................................................2-21
Entry Lighting.................................................3-18
Event Data Recorders (EDR)............................7-10
Exit Lighting...................................................3-18
Extender, Safety Belt.......................................1-47
F
Filter
Engine Air Cleaner......................................5-19
Finish Damage.............................................5-101
Fixed Mast Antenna.......................................3-102
Flash-to-Pass................................................... 3-9
Flat Tire........................................................5-74
Flat Tire, Changing.........................................5-74
Flat Tire, Storing.............................................5-90
5

Mirrors (cont.)
Outside Convex Mirror.................................2-35
Outside Heated Mirrors................................2-36
Outside Power Mirrors..................................2-34
MyGMLink.com................................................ 7-3
N
Navigation/Radio System..................................3-94
New Vehicle Break-In......................................2-19
Normal Maintenance Replacement Parts............6-14
O
Odometer......................................................3-30
Off-Road Recovery..........................................4-13
Oil
Engine.......................................................5-14
Pressure Gage............................................3-42
Older Children, Restraints................................1-47
Online Owner Center........................................ 7-3
OnStar
®System.............................................2-37
Operating Your All-Wheel-Drive Vehicle Off
Paved Roads..............................................4-16
Other Warning Devices...................................... 3-6
Outlet Adjustment............................................3-25Outside
Automatic Dimming Mirror with Curb View
Assist.....................................................2-36
Convex Mirror.............................................2-35
Heated Mirrors............................................2-36
Power Mirrors.............................................2-34
Overheated Engine Protection Operating Mode....5-30
Owner Checks and Services.............................. 6-9
Owners, Canadian............................................... ii
P
Park (P)
Shifting Into................................................2-28
Shifting Out of............................................2-29
Parking
Brake........................................................2-27
Over Things That Burn.................................2-30
Passenger Airbag Status Indicator.....................3-32
Passenger Sensing System..............................1-79
Passing.........................................................4-14
Passlock
®......................................................2-19
Power
Accessory Outlets........................................3-19
Door Locks.................................................. 2-9
Electrical System.......................................5-105
9