
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
Vehicle Care 299
Engine Coolant
The cooling system in the vehicle is
filled with DEX-COOL®engine
coolant. This coolant is designed to
remain in the vehicle for 5 years or
240 000 km (150,000 mi), whichever
occurs first.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating 0301.
What to Use
{Warning
Adding only plain water or some
other liquid to the cooling system
can be dangerous. Plain water
and other liquids, can boil before
the proper coolant mixture will.
The coolant warning system is set
for the proper coolant mixture.
With plain water or the wrong
mixture, the engine could get too
hot but you would not get the
(Continued)
Warning (Continued)
overheat warning. The engine
could catch fire and you or others
could be burned. Use a 50/
50 mixture of clean, drinkable
water and DEX-COOL coolant.
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture:
. Gives freezing protection down
to−37 °C (−34 °F), outside
temperature.
. Gives boiling protection up to
129 °C (265 °F), engine
temperature.
. Protects against rust and
corrosion.
. Will not damage aluminum parts.
. Helps keep the proper engine
temperature.
Caution
If improper coolant mixture,
inhibitors, or additives are used in
the vehicle cooling system, the
engine could overheat and be
damaged. Too much water in the
mixture can freeze and crack
engine cooling parts. The repairs
would not be covered by the
vehicle warranty. Use only the
proper mixture of engine coolant
for the cooling system. See
Recommended Fluids and
Lubricants 0384.
Never dispose of engine coolant by
putting it in the trash, or by pouring
it on the ground, or into sewers,
streams, or bodies of water. Have
the coolant changed by an
authorized service center, familiar
with legal requirements regarding
used coolant disposal. This will help
protect the environment and your
health.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
300 Vehicle Care
Checking Coolant
The coolant surge tank is in the
engine compartment on the
passenger side of the vehicle. See
Engine Compartment
Overview0287.
The vehicle must be on a level
surface when checking the coolant
level.
Check to see if coolant is visible in
the coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, wait until it cools down. The
coolant level should be at or above the FULL COLD mark. If it is not,
there may be a leak in the cooling
system.
If coolant is visible but the coolant
level is not at or above the FULL
COLD mark, see
“How to Add
Coolant to the Coolant Surge Tank,”
following.
How to Add Coolant to the
Coolant Surge Tank
{Warning
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.
Caution
This vehicle has a specific
coolant fill procedure. Failure to
follow this procedure could cause
the engine to overheat and be
severely damaged.
{Warning
Steam and scalding liquids from a
hot cooling system can blow out
and burn you badly. Never turn
the cap when the cooling system,
including the surge tank pressure
cap, is hot. Wait for the cooling
system and surge tank pressure
cap to cool.
If no coolant is visible in the surge
tank, add coolant.
1. 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
Vehicle Care 301
Turn the pressure cap slowly
counterclockwise about one full
turn. If a hiss is heard, wait for
that to stop. A hiss means
there is still some pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper mixture to the FULL
COLD mark.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90 °C (195 °F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge
tank until the level reaches the
FULL COLD mark.
5. Replace the pressure cap tightly. 6. Verify coolant level after the
engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6.
Caution
If the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
Caution
Running the engine without
coolant may cause damage or a
fire. Vehicle damage would not be
covered by the vehicle warranty.
The vehicle has several indicators
to warn of engine overheating. There is a coolant temperature
gauge in the vehicle's instrument
cluster. See
Engine Coolant
Temperature Gauge 0139.
In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC). See
Engine Cooling System Messages
0 161 andEngine Power
Messages 0162.
If the decision is made not to lift the
hood when this warning appears,
get service help right away.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Check to see if the engine cooling
fan(s) are running. If the engine is
overheating, the fans should be
running. If they are not, do not
continue to run the engine, and
have the vehicle serviced.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
302 Vehicle Care
If Steam is Coming from the
Engine Compartment
{Warning
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.
If you keep driving when the
engine is overheated, the liquids
in it can catch fire. You or others
could be badly burned. Stop the
engine if it overheats, and get out
of the vehicle until the engine
is cool.
If No Steam is Coming from
the Engine Compartment
The ENGINE OVERHEATED STOP
ENGINE or the ENGINE
OVERHEATED IDLE ENGINEmessage, along with a low coolant
condition, can indicate a serious
problem.
If there is an engine overheat
warning, but no steam is seen or
heard, the problem may not be too
serious. Sometimes the engine can
get a little too hot when the vehicle:
.
Climbs a long hill on a hot day.
. Stops after high-speed driving.
. Idles for long periods in traffic.
. Tows a trailer; see Trailer
Towing 0271.
If the ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message appears with no sign of
steam, try this for a minute or so: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the
highest fan speed. Open the
windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral), and let the
engine idle. If the engine coolant temperature
gauge is no longer in the overheat
zone or an overheat warning no
longer displays, the vehicle can be
driven. Continue to drive the vehicle
slowly for about 10 minutes. Keep a
safe vehicle distance from the
vehicle in front. If the warning does
not come back on, continue to drive
normally and have the cooling
system checked for proper fill and
function.
If the warning continues, pull over,
stop, and park the vehicle
right away.
If there is still no sign of steam and
the 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
five minutes while the vehicle is
parked. If the warning is still there,
turn off the engine and get everyone
out of the vehicle until it cools down.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
316 Vehicle Care
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses
The wiring circuits in the vehicle are
protected from short circuits by
fuses. This greatly reduces the
chance of fires caused by electrical
problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.Fuses of the same amperage can
be temporarily borrowed from
another fuse location, if a fuse goes
out. Replace the fuse as soon as
you can.
Engine Compartment
Fuse Block
The engine compartment fuse block
is in the engine compartment, on
the driver side of the vehicle.
Lift the cover to access the fuse
block.
Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.
A fuse puller is available in the left
instrument panel fuse block.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
418 Index
Driving (cont'd)Characteristics and
Towing Tips . . . . . . . . . . . . . . . . . 268
Defensive . . . . . . . . . . . . . . . . . . . . . 201
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . 201
For Better Fuel Economy . . . . . . . 26
Hill and Mountain Roads . . . . . . 209
If the Vehicle is Stuck . . . . . . . . . .211
Loss of Control . . . . . . . . . . . . . . . 203
Off-Road . . . . . . . . . . . . . . . . . . . . . 203
Off-Road Recovery . . . . . . . . . . . 202
Vehicle Load Limits . . . . . . . . . . . 212
Wet Roads . . . . . . . . . . . . . . . . . . . 208
Winter . . . . . . . . . . . . . . . . . . . . . . . . 209
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . 191
E
E85 or FlexFuel . . . . . . . . . . . . . . . . 265
Electrical Equipment,Add-On . . . . . . . . . . . . . . . . . . . . . . . 282
Electrical System Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 316
Fuses . . . . . . . . . . . . . . . . . . . . . . . . 316
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . 320, 323
Overload . . . . . . . . . . . . . . . . . . . . . 315 Electrical System (cont'd)
Rear Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . 325
Emergency
OnStar
®. . . . . . . . . . . . . . . . . . . . . . 406
Engine Air Cleaner/Filter . . . . . . . . . . . . . 297
Check and Service EngineSoon Light . . . . . . . . . . . . . . . . . . 144
Compartment Overview . . . . . . . 287
Coolant . . . . . . . . . . . . . . . . . . . . . . . 299
Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . 139
Coolant Temperature
Warning Light . . . . . . . . . . . . . . . 148
Cooling System . . . . . . . . . . . . . . . 298
Cooling System Messages . . . 161
Drive Belt Routing . . . . . . . . . . . . 390
Exhaust . . . . . . . . . . . . . . . . . . . . . . 226
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Heater . . . . . . . . . . . . . . . . . . . . . . . . 222
Oil Life System . . . . . . . . . . . . . . . 292
Oil Messages . . . . . . . . . . . . . . . . . 161
Oil Pressure Gauge . . . . . . . . . . 138
Oil Pressure Light . . . . . . . . . . . . 149
Overheating . . . . . . . . . . . . . . . . . . 301
Power Messages . . . . . . . . . . . . . 162
Running While Parked . . . . . . . . 227 Engine (cont'd)
Starting . . . . . . . . . . . . . . . . . . . . . . . 220
Entry Lighting . . . . . . . . . . . . . . . . . . . 188
Equipment, Towing . . . . . . . . . . . . . 274
Event Data Recorders . . . . . . . . . . 403
Exit Lighting . . . . . . . . . . . . . . . . . . . . 188
Extended Parking . . . . . . . . . . . . . . . 226
Extender, Safety Belt . . . . . . . . . . . . 84
Exterior Lamp Controls . . . . . . . . . 181
Exterior Lamps Off Reminder . . . 183
F
Fan Engine . . . . . . . . . . . . . . . . . . . . . . . . 303
Features Memory . . . . . . . . . . . . . . . . . . . . . . . . . 12
Filter, Engine Air Cleaner . . . . . . . . . . . 297
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 183
Flashers, Hazard Warning . . . . . . 185
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . 346
Changing . . . . . . . . . . . . . . . . . . . . . 347
FlexFuel E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Floor Mats . . . . . . . . . . . . . . . . . . . . . . 373
Fluid AutomaticTransmission . . . . . . . . . . . 293, 296
Brakes . . . . . . . . . . . . . . . . . . . . . . . . 305

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 7/5/16
422 Index
Mirrors (cont'd)Folding . . . . . . . . . . . . . . . . . . . . . . . . . 55
Heated . . . . . . . . . . . . . . . . . . . . . . . . . 55
Manual Rearview . . . . . . . . . . . . . . . 57
Power . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Tilt in Reverse . . . . . . . . . . . . . . . . . . 56
Mirrors, Interior Rearview . . . . . . . . 57
Monitor System, Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 335
N
Navigation
OnStar®. . . . . . . . . . . . . . . . . . . . . . 407
Net, Convenience . . . . . . . . . . . . . . 122
New Vehicle Break-In . . . . . . . . . . . 216
Noise Control System . . . . . . . . . . 308
O
Object Detection System Messages . . . . . . . . . . . . . . . . . . . . . 163
Odometer . . . . . . . . . . . . . . . . . . . . . . . 137 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Off-Road . . . . . . . . . . . . . . . . . . . . . . . 203 Driving . . . . . . . . . . . . . . . . . . . . . . . . 203
Recovery . . . . . . . . . . . . . . . . . . . . . 202
Oil Engine . . . . . . . . . . . . . . . . . . . . . . . . 290
Engine Oil Life System . . . . . . . 292
Engine Oil Pressure Gauge . . . 138 Oil (cont'd)
Messages . . . . . . . . . . . . . . . . . . . . 161
Pressure Light . . . . . . . . . . . . . . . . 149
Older Children, Restraints . . . . . . . 98
Online Owner Center . . . . . . . . . . . 394
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . 403
OnStar
®Additional
Information . . . . . . . . . . . . . . . . . . . . 410
OnStar
®Connections . . . . . . . . . . . 407
OnStar®Diagnostics . . . . . . . . . . . . 409
OnStar®Emergency . . . . . . . . . . . . 406
OnStar®Navigation . . . . . . . . . . . . . 407
OnStar®Overview . . . . . . . . . . . . . . 405
OnStar®Security . . . . . . . . . . . . . . . 406
Operation Fog Lamps . . . . . . . . . . . . . . . . . . . 186
Ordering Service Publications . . . . . . . . . . 400
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . 130
Overheating, Engine . . . . . . . . . . . . 301
P
Park Shifting Into . . . . . . . . . . . . . . . . . . . 224
Shifting Out of . . . . . . . . . . . . . . . . 225
Parking Brake . . . . . . . . . . . . . . . . . . . . . . . . . 237 Parking (cont'd)
Brake and P (Park)
Mechanism Check . . . . . . . . . . 310
Extended . . . . . . . . . . . . . . . . . . . . . 226
Over Things That Burn . . . . . . . 225
Parking Assist . . . . . . . . . . . . . . . . . . 252
Parking or Backing Assistance Systems . . . . . . . . . . 252
Passenger Airbag Status
Indicator . . . . . . . . . . . . . . . . . . . . . . 142
Passenger Compartment Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Passenger Sensing System . . . . . 92
Perchlorate Materials Requirements, California . . . . . . 284
Personalization Vehicle . . . . . . . . . . . . . . . . . . . . . . . 170
Power
Door Locks . . . . . . . . . . . . . . . . . . . . . 42
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Outlets . . . . . . . . . . . . . . . . . . . . . . . 130
Protection, Battery . . . . . . . . . . . . 189
Retained Accessory (RAP) . . . 223
Seat Adjustment . . . . . . . . . . . . . . . . 64
Windows . . . . . . . . . . . . . . . . . . . . . . . 58
Power Assist Steps . . . . . . . . . . . . . . 49
Pregnancy, Using Safety Belts . . . 83