cooling GMC YUKON 2020 Owner's Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
172 Lighting
interior lamps remain on for a set
amount of time, then automatically
turn off.
The exterior lamps turn off
immediately by turning the exterior
lamp control off.
This feature can be changed. See
Vehicle Personalization0152.
Battery Load
Management
The vehicle has Electric Power
Management (EPM), which
estimates the battery's temperature
and state of charge. It then adjusts
the voltage for best performance
and extended life of the battery.
When the battery's state of charge
is low, the voltage is raised slightly
to quickly bring the charge back up.
When the state of charge is high,
the voltage is lowered slightly to
prevent overcharging. The voltmeter
gauge or the voltage display on the
Driver Information Center (DIC),
if equipped, may show the voltage moving up or down. This is normal.
If there is a problem, an alert will be
displayed.
The battery can be discharged at
idle if the electrical loads are very
high. This is true for all vehicles.
This is because the generator
(alternator) may not be spinning fast
enough at idle to produce all the
power that is needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, fog
lamps, rear window defogger,
climate control fan at high speed,
heated seats, engine cooling fans,
trailer loads, and loads plugged into
accessory power outlets.
EPM works to prevent excessive
discharge of the battery. It does this
by balancing the generator's output
and the vehicle's electrical needs.
It can increase engine idle speed to
generate more power, whenever
needed. It can temporarily reduce
the power demands of some
accessories.Normally, these actions occur in
steps or levels, without being
noticeable. In rare cases at the
highest levels of corrective action,
this action may be noticeable to the
driver. If so, a DIC message might
be displayed and it is recommended
that the driver reduce the electrical
loads as much as possible.
Battery Power Protection
This feature shuts off the dome and
reading lamps if they are left on for
more than 10 minutes when the
ignition is off. This will keep the
battery from running down.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Climate Controls 175
Climate Controls
Climate Control Systems
Dual Automatic ClimateControl System . . . . . . . . . . . . . 175
Rear Climate Control System . . . . . . . . . . . . . . . . . . . . . . 179
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . 180
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . 181
Service . . . . . . . . . . . . . . . . . . . . . . . 182
Climate Control
Systems
Dual Automatic Climate
Control System
With this system the heating,
cooling, and ventilation in the
vehicle can be controlled. Some
climate control settings can be
changed. See “Climate and Air
Quality” underVehicle
Personalization 0152.
1. Driver Temperature Control
2. A/C (Air Conditioning) 3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger Temperature
Control
7. SYNC (Synchronized Temperature)
8. Rear Window Defogger
9. RCTRL (Rear Climate Control Lockout)
10. Rear Temperature Control
11. Rear Air Delivery Mode Control
12. Rear Fan Control
13. Front Climate Control Power Button
14. Rear AUTO (Automatic Operation)
15. Rear Climate Control Power Button
16. Air Recirculation
17. AUTO (Automatic Operation)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 193
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody or
chassis, or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, driveline,
steering, suspension, wheels, tires,
and exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See theMaintenance
Schedule 0379.
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep-standing or flowing water.
{Warning
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.
Allow extra following distance.
. Pass with caution.
. Keep windshield wiping
equipment in good shape.
. Keep the windshield washer fluid
reservoir filled.
. Have good tires with proper
tread depth. See Tires0326.
. Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips include:

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
194 Driving and Operating
.Keep the vehicle serviced and in
good shape.
. Check all fluid levels and brakes,
tires, cooling system, and
transmission.
. Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and
(Continued)
Warning (Continued)
loss of steering assist. Always
have the engine running and the
vehicle in gear.
. Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the
center line.
. Be alert on top of hills;
something could be in your lane
(e.g., stalled car, crash).
. Pay attention to special road
signs (e.g., falling rocks area,
winding roads, long grades,
passing or no-passing zones)
and take appropriate action.
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and
the road creates less traction or
grip, so drive carefully. Wet ice can
occur at about 0 °C (32 °F) when freezing rain begins to fall. Avoid
driving on wet ice or in freezing rain
until roads can be treated.
For Slippery Road Driving:
.
Accelerate gently. Accelerating
too quickly causes the wheels to
spin and makes the surface
under the tires slick.
. Turn on Traction Control. See
Traction Control/Electronic
Stability Control 0226.
. The Antilock Brake System
(ABS) improves vehicle stability
during hard stops, but the
brakes should be applied sooner
than when on dry pavement.
See Antilock Brake System
(ABS) 0224.
. Allow greater following distance
and watch for slippery spots. Icy
patches can occur on otherwise
clear roads in shaded areas.
The surface of a curve or an
overpass can remain icy when
the surrounding roads are clear.
Avoid sudden steering
maneuvers and braking while
on ice.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
218 Driving and Operating
Grade Braking is not available when
Range Selection Mode is active.
SeeTow/Haul Mode 0218.
While using Range Selection Mode,
cruise control and the Tow/Haul
Mode can be used.
Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
The repair will not be covered by
the vehicle warranty. If the vehicle
is stuck, do not spin the tires.
When stopping on a hill, use the
brakes to hold the vehicle in
place.
Tow/Haul Mode
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce
shift cycling. This provides
increased performance, vehicle
control, and enhanced transmission
and engine cooling when driving
down steep hills or mountain
grades, towing, or hauling heavy
loads. The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See
Tow/Haul Mode Light 0139 and
Hill and Mountain Roads 0193.
Also see “Tow/Haul Mode” under
Towing Equipment 0270.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “Tow/Haul Mode” listed
previously and Manual Mode0216.
Tow/Haul Mode Grade Braking
assists in maintaining desired
vehicle speeds when driving on
downhill grades by using the engine
and transmission to slow the
vehicle.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
264 Driving and Operating
2. Start the engine and shift intoa gear.
3. Release the parking brake.
4. Let up on the brake pedal.
5. Drive slowly until the tires are clear of the chocks.
6. Stop and have someone pick up and store the chocks.
7. Slowly pull the trailer from the water.
8. Once the vehicle and trailer have been driven from the
sloped part of the boat ramp,
the vehicle can be shifted from
four-wheel-drive high. Shift into
the drive mode that is
appropriate for the road
conditions.
Caution
If the vehicle tires begin to spin
and the vehicle begins to slide
toward the water, remove your
foot from the accelerator pedal
(Continued)
Caution (Continued)
and apply the brake pedal. Seek
help to have the vehicle towed up
the ramp.
Maintenance when Trailer
Towing
The vehicle needs service more
often when used to tow trailers. See
Maintenance Schedule 0379. It is
especially important to check the
automatic transmission fluid, engine
oil, axle lubricant, belts, cooling
system, and brake system before
and during each trip.
Check periodically that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling when Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 300.
Trailer Towing
Caution
Towing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer
for important information about
towing a trailer with the vehicle.
Trailer Weight
{Warning
Never exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring
the weight, speed, altitude, road
grades, outside temperature,
dimensions of the front of the trailer,
and how frequently the vehicle is
used to tow a trailer.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 281
Vehicle Care
General Information
General Information . . . . . . . . . . 282
California Proposition65 Warning . . . . . . . . . . . . . . . . . 282
California Perchlorate Materials Requirements . . . . . 283
Accessories and Modifications . . . . . . . . . . . . . . . . 283
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 283
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 284
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 286
Engine Oil . . . . . . . . . . . . . . . . . . . . 289
Engine Oil Life System . . . . . . . 291
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 292
Automatic Transmission Fluid (10-Speed Transmission) . . . 295
Engine Air Cleaner/Filter . . . . . . 296
Cooling System . . . . . . . . . . . . . . 297
Engine Overheating . . . . . . . . . . 300
Engine Fan . . . . . . . . . . . . . . . . . . . 302
Washer Fluid . . . . . . . . . . . . . . . . . 302
Brakes . . . . . . . . . . . . . . . . . . . . . . . 303 Brake Fluid . . . . . . . . . . . . . . . . . . . 304
Battery - North America . . . . . . 305
Four-Wheel Drive . . . . . . . . . . . . . 305
Front Axle . . . . . . . . . . . . . . . . . . . . 306
Rear Axle . . . . . . . . . . . . . . . . . . . . 306
Noise Control System . . . . . . . . 306
Starter Switch Check . . . . . . . . . 308
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 308
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 308
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 309
Wiper Blade Replacement . . . . 309
Glass Replacement . . . . . . . . . . 310
Windshield Replacement . . . . . 310
Gas Strut(s) . . . . . . . . . . . . . . . . . . 310
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 312
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 312
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 312
LED Lighting . . . . . . . . . . . . . . . . . 312
Fog Lamps . . . . . . . . . . . . . . . . . . . 312
Back-Up Lamps . . . . . . . . . . . . . . 313
License Plate Lamp . . . . . . . . . . 314
Electrical System
Electrical System Overload . . . 314
Fuses and Circuit Breakers . . . 315
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 315
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 320
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 323
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 325
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 326
All-Season Tires . . . . . . . . . . . . . . 327
Winter Tires . . . . . . . . . . . . . . . . . . 328
Low-Profile Tires . . . . . . . . . . . . . 328
All-Terrain Tires . . . . . . . . . . . . . . . 328
Tire Sidewall Labeling . . . . . . . . 329
Tire Designations . . . . . . . . . . . . . 330
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 331
Tire Pressure . . . . . . . . . . . . . . . . . 333
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . 334
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . 335
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . 336
Tire Inspection . . . . . . . . . . . . . . . . 340

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 287
1. Positive (+) Terminal. SeeJump Starting - North America
0360.
2. Battery - North America 0305.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0297.
4. Engine Air Cleaner/Filter 0296.
5. Automatic Transmission Dipstick. See “How to Check
Automatic Transmission Fluid”
under Automatic Transmission
Fluid (6-Speed Transmission)
0 292 or
Automatic Transmission Fluid
(10-Speed Transmission)
0 295.
6. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0360.
7. Engine Cooling Fans (Out of View). See Cooling System
0 297.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0289. 9. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil 0289.
10. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 302.
11. Brake Fluid Reservoir. See Brake Fluid 0304.
12. Engine Compartment Fuse
Block 0315.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 289
1. Positive (+) Terminal. SeeJump Starting - North America
0360.
2. Battery - North America 0305.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0297.
4. Engine Air Cleaner/Filter 0296.
5. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0360.
6. Engine Cooling Fans (Out of View). See Cooling System
0 297.
7. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0289.
8. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil 0289.
9. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 302.
10. Brake Fluid Reservoir. See Brake Fluid 0304. 11.
Engine Compartment Fuse
Block 0315.
Engine Oil
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
.
Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
“Selecting the Right Engine Oil”
in this section.
. Check the engine oil level
regularly and maintain the
proper oil level. See “Checking
Engine Oil” and“When to Add
Engine Oil” in this section.
. Change the engine oil at the
appropriate time. See Engine Oil
Life System 0291.
. Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.
Checking Engine Oil
If equipped, the ENGINE OIL LOW
ADD OIL message displays when
the engine oil level may be too low.
Check the oil level before filling to
the recommended level. If the oil is
not low and this message remains
on, see your dealer.
Check the engine oil level regularly,
every 650 km (400 mi), especially
prior to a long trip. The engine oil
dipstick handle is a loop. See
Engine Compartment Overview
0286 for the location.
{Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
Follow these guidelines:
. To get an accurate reading, park
the vehicle on level ground.
Check the engine oil level after
the engine has been off for at
least two hours. Checking the

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 297
{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. Use caution
when working on the engine. Do
not start the engine or drive the
vehicle with the air cleaner/filter
off, as flames may be present if
the engine backfires.
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 0300.