2018 GMC YUKON engine overheat

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Driving and Operating 215
Caution
Cranking the engine for long
periods of time, by returning the
ignition to the START position
immediately after cranking has
ended, can overheat and damage
the cranking motor, and drain the
battery. Wait at least 15 seconds
between each try, to let the
cranking motor cool down.
2. If the engine does not start after five to 10 seconds,
especially in very cold weather
(below −18 °C or 0 °F), it could
be flooded with too much
gasoline. Try pushing the
accelerator pedal all the way to
the floor and holding it there as
you press ENGINE START/
STOP, for up to a maximum of
15 seconds. Wait at least
15 seconds between each try,
to allow the cranking motor to
cool down. When the engine
starts, let go of the button, and
the accelerator. If the vehicle starts briefly but then stops
again, do the same thing. This
clears the extra gasoline from
the engine. Do not race the
engine immediately after
starting it. Operate the engine
and transmission gently until
the oil warms up and lubricates
all moving parts.
Engine Heater
{Warning
Do not plug in the engine block
heater while the vehicle is parked
in a garage or under a carport.
Property damage or personal
injury may result. Always park the
vehicle in a clear open area away
from buildings or structures.
If equipped, the engine heater can
provide easier starting and better
fuel economy during engine
warm-up in cold weather conditions
at or below −18 °C (0 °F). Vehicles
with an engine heater should be
plugged in at least four hours before starting. There may be an internal
thermostat in the plug end of the
cord, which will prevent engine
heater operation at temperatures
above
−18 °C (0 °F).
To Use the Engine Heater
1. Turn off the engine.
2. Open the hood and unwrap the
electrical cord. The cord is by
the left front fender, next to the
engine compartment fuse
block.
Check the heater cord for
damage. If it is damaged, do
not use it. See your dealer for
a replacement. Inspect the
cord for damage yearly.
3. Plug the cord into a normal, grounded 110-volt AC outlet.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
216 Driving and Operating
{Warning
Improper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire.. Plug the cord into a
three-prong electrical utility
receptacle that is protected
by a ground fault detection
function. An ungrounded
outlet could cause an
electric shock.
. Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension
cord in good operating
condition, or using a
damaged heater or
extension cord, could make
(Continued)
Warning (Continued)
it overheat and cause a fire,
property damage, electric
shock, and injury.
. Do not operate the vehicle
with the heater cord
permanently attached to the
vehicle. Possible heater
cord and thermostat
damage could occur.
. While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord.
. Before starting the vehicle,
unplug the cord, reattach
the cover to the plug, and
securely fasten the cord.
Keep the cord away from
any moving parts.
4. Before starting the engine, be sure to unplug and store the
cord as it was before to keep it away from moving engine
parts. If you do not, it could be
damaged.
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP)
Some vehicle accessories may be
used after the ignition is turned off.
The power windows and sunroof,
if equipped, will continue to work for
up to 10 minutes or until any door is
opened.
The infotainment system will
continue to work for 10 minutes,
until the driver door is opened,
or until the ignition is turned on or
placed in ACC/ACCESSORY.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Driving and Operating 217
Shifting Into Park
{Warning
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. If you have left the engine
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when you are on
fairly level ground, use the steps
that follow. If the vehicle has a
four-wheel-drive transfer case
with a N (Neutral) position, and
the transfer case is in N (Neutral),
the vehicle will be free to roll,
even if the shift lever is in
P (Park). Be sure the transfer
case is in a drive gear. If towing a
trailer, seeDriving Characteristics
and Towing Tips 0263.
1. Hold the brake pedal down, then set the parking brake. See
Parking Brake 0232. 2. Move the shift lever into the
P (Park) position by pulling the
shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case is in a drive gear –not in
N (Neutral).
4. Turn the ignition off.
Leaving the Vehicle with the
Engine Running
{Warning
It can be dangerous to leave the
vehicle with the engine running.
The vehicle could move suddenly
if the shift lever is not fully in
P (Park) with the parking brake
firmly set.
If you have four-wheel drive and
the transfer case is in N (Neutral),
the vehicle will be free to roll,
even if the shift lever is in
P (Park). So be sure the transfer
case is in a drive gear –not in
N (Neutral).
(Continued)
Warning (Continued)
And, if you leave the vehicle with
the engine running, it could
overheat and even catch fire. You
or others could be injured. Do not
leave the vehicle with the engine
running unless you have to.
If you have to leave the vehicle with
the engine running, be sure the
vehicle is in P (Park) and the
parking brake is firmly set before
you leave it. After you move the shift
lever into P (Park), hold the regular
brake pedal down. Then, see if you
can move the shift lever away from
P (Park) without first pulling it toward
you. If you can, it means that the
shift lever was not fully locked into
P (Park).
Torque Lock
If you are parking on a hill and you
do not shift the transmission into
P (Park) properly, the weight of the
vehicle may put too much force on
the parking pawl in the
transmission. You may find it difficult

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
266 Driving and Operating
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, seeEngine Overheating 0298.
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill. 2. Have someone place chocks
under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0376.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
Do not tow a trailer during break-in.
See New Vehicle Break-In 0209.
Before towing a trailer, see
"Hands-Free Operation" under
Liftgate 045.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
280 Vehicle Care
Vehicle Care
General Information
General Information . . . . . . . . . . 281
California Proposition65 Warning . . . . . . . . . . . . . . . . . 281
California Perchlorate Materials Requirements . . . . . 282
Accessories and Modifications . . . . . . . . . . . . . . . . 282
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 282
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 283
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 284
Engine Oil . . . . . . . . . . . . . . . . . . . . 287
Engine Oil Life System . . . . . . . 289
Automatic Transmission Fluid (6 Speed Transmission) . . . . . 290
Automatic Transmission Fluid (8 and 10 Speed
Transmission) . . . . . . . . . . . . . . . 293
Engine Air Cleaner/Filter . . . . . . 294
Cooling System . . . . . . . . . . . . . . 295
Engine Overheating . . . . . . . . . . 298
Engine Fan . . . . . . . . . . . . . . . . . . . 300
Washer Fluid . . . . . . . . . . . . . . . . . 300 Brakes . . . . . . . . . . . . . . . . . . . . . . . 301
Brake Fluid . . . . . . . . . . . . . . . . . . . 302
Battery - North America . . . . . . 303
Four-Wheel Drive . . . . . . . . . . . . . 303
Front Axle . . . . . . . . . . . . . . . . . . . . 304
Rear Axle . . . . . . . . . . . . . . . . . . . . 305
Noise Control System . . . . . . . . 305
Starter Switch Check . . . . . . . . . 306
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 307
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 307
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 307
Wiper Blade Replacement . . . . 308
Glass Replacement . . . . . . . . . . 309
Windshield Replacement . . . . . 309
Gas Strut(s) . . . . . . . . . . . . . . . . . . 309
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 310
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 311
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 311
LED Lighting . . . . . . . . . . . . . . . . . . 311
Fog Lamps . . . . . . . . . . . . . . . . . . . 311
Back-Up Lamps . . . . . . . . . . . . . . 311
License Plate Lamp . . . . . . . . . . 312
Electrical System
Electrical System Overload . . . 313
Fuses and Circuit Breakers . . . 313
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 314
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 318
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 321
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 323
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 324
All-Season Tires . . . . . . . . . . . . . . 325
Winter Tires . . . . . . . . . . . . . . . . . . 325
Low-Profile Tires . . . . . . . . . . . . . 326
All-Terrain Tires . . . . . . . . . . . . . . . 326
Tire Sidewall Labeling . . . . . . . . 326
Tire Designations . . . . . . . . . . . . . 327
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 328
Tire Pressure . . . . . . . . . . . . . . . . . 331
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . 332
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . 333
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . 334
Tire Inspection . . . . . . . . . . . . . . . . 337

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
290 Vehicle Care
best conditions, the oil life system
may indicate that an oil change is
not necessary for up to a year. The
engine oil and filter must be
changed at least once a year and,
at this time, the system must be
reset. Your dealer has trained
service people who will perform this
work and reset the system. It is also
important to check the oil regularly
over the course of an oil drain
interval and keep it at the proper
level.
If the system is ever reset
accidentally, the oil must be
changed at 5 000 km (3,000 mi)
since the last oil change.
Remember to reset the oil life
system whenever the oil is changed.
How to Reset the Engine Oil
Life System
Reset the system whenever the
engine oil is changed so that the
system can calculate the next
engine oil change. Always reset the
engine oil life to 100% after every oil
change. It will not reset itself. To
reset the engine oil life system:1. Display the REMAINING OIL
LIFE on the DIC. See Driver
Information Center (DIC) 0154.
2. Press and hold
V. The oil life
will change to 100%.
The oil life system can also be reset
as follows: 1. Display the REMAINING OIL LIFE on the DIC. See Driver
Information Center (DIC) 0154.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. Display the REMAINING OIL LIFE on the DIC. If the display
shows 100%, the system is
reset.
If the CHANGE ENGINE OIL SOON
message comes back on when the
vehicle is started and/or the
REMAINING OIL LIFE is near 0%,
the engine oil life system has not
been reset. Repeat the procedure.
Automatic Transmission
Fluid (6 Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The only
reason for fluid loss is a
transmission leak or overheated
transmission. If a small leak is
suspected, then use the following
checking procedures to check the
fluid level. However, if there is a
large leak, then it may be necessary
to have the vehicle towed to a
dealer service department and have
it repaired before driving the vehicle
further.
Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may
not be covered by the vehicle
warranty. Always use the (Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Vehicle Care 291
Caution (Continued)
automatic transmission fluid listed
inRecommended Fluids and
Lubricants 0384.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 376. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants 0384.
How to Check Automatic
Transmission Fluid
Caution
Too much or too little fluid can
damage the transmission. Too
much can mean that some of the
fluid could come out and fall on
hot engine parts or exhaust
system parts, starting a fire. Too
little fluid could cause the (Continued)
Caution (Continued)
transmission to overheat. Be sure
to get an accurate reading if
checking the transmission fluid.
Before checking the fluid level,
prepare the vehicle: 1. Start the engine and park the vehicle on a level surface.
Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever
through each gear range,
pausing for about
three seconds in each range.
Then, move the shift lever back
to P (Park).
4. Allow the engine to idle (500– 800 rpm) for at least
one minute. Slowly release the
brake pedal.
5. Keep the engine running and check the transmission fluid
temperature on the Driver Information Center (DIC). See
Driver Information Center (DIC)
0
154.
6. Using the transmission fluid temperature reading, determine
and perform the appropriate
check procedure. If the
transmission fluid temperature
reading is not within the
required temperature ranges,
allow the vehicle to cool,
or operate the vehicle until the
appropriate transmission fluid
temperature is reached.
Cold Check Procedure
Use this procedure only as a
reference to determine if the
transmission has enough fluid to be
operated safely until a hot check
procedure can be made. The hot
check procedure is the most
accurate method to check the fluid
level. Perform the hot check
procedure at the first opportunity.
Use this cold check procedure to
check fluid level when the
transmission temperature is
between 27 °C and 32 °C (80 °F and
90 °F).

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Vehicle Care 295
{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. The air
cleaner not only cleans the air; it
helps to stop flames if the engine
backfires. Use caution when
working on the engine and do not
drive with the air cleaner/filter off.
Caution
If the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always
have the air cleaner/filter in place
when driving.
Cooling System
The cooling system allows the
engine to maintain the correct
working temperature.
1. Coolant Surge Tank
2. Coolant Surge TankPressure Cap
3. Engine Electric Cooling Fan(s)
{Warning
An underhood electric fan can
start up even when the engine is
not running and can cause injury.
Keep hands, clothing, and tools
away from any underhood
electric fan.
{Warning
Do not touch heater or radiator
hoses, or other engine parts.
They can be very hot and can
burn you. Do not run the engine if
there is a leak; all coolant could
leak out. That could cause an
engine fire and can burn you. Fix
any leak before driving the
vehicle.
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 0298.