engine compartment overview GMC SIERRA 2020 Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 327
Vehicle Care
General Information
General Information . . . . . . . . . . 328
California Proposition65 Warning . . . . . . . . . . . . . . . . . 329
California Perchlorate Materials Requirements . . . . . 329
Accessories and Modifications . . . . . . . . . . . . . . . . 329
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 330
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 330
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 332
Engine Oil . . . . . . . . . . . . . . . . . . . . 339
Engine Oil Life System . . . . . . . 341
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Filter Life System . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Cleaner/Filter . . . . . . 344
Cooling System . . . . . . . . . . . . . . 346
Engine Overheating . . . . . . . . . . 351
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 352
Engine Fan . . . . . . . . . . . . . . . . . . . 353 Power Steering Fluid . . . . . . . . . 354
Washer Fluid . . . . . . . . . . . . . . . . . 354
Brakes . . . . . . . . . . . . . . . . . . . . . . . 355
Brake Pad Life System . . . . . . . 356
Brake Fluid . . . . . . . . . . . . . . . . . . . 357
Battery - North America . . . . . . 358
Four-Wheel Drive . . . . . . . . . . . . . 361
Front Axle . . . . . . . . . . . . . . . . . . . . 361
Rear Axle . . . . . . . . . . . . . . . . . . . . 362
Noise Control System . . . . . . . . 362
Starter Switch Check . . . . . . . . . 363
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 363
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 363
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 364
Wiper Blade Replacement . . . . 364
Windshield Replacement . . . . . 365
Gas Strut(s) . . . . . . . . . . . . . . . . . . 365
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 366
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 367
Halogen Bulbs . . . . . . . . . . . . . . . . 367
LED Lighting . . . . . . . . . . . . . . . . . 367 Headlamps, Front Turn Signal,
Sidemarker, and Parking
Lamps . . . . . . . . . . . . . . . . . . . . . . 367
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 368
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 369
License Plate Lamp . . . . . . . . . . 369
Electrical System
Electrical System Overload . . . 370
Fuses and Circuit Breakers . . . 370
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 371
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 374
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 376
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 379
All-Season Tires . . . . . . . . . . . . . . 379
Winter Tires . . . . . . . . . . . . . . . . . . 380
Low-Profile Tires . . . . . . . . . . . . . 380
All-Terrain Tires . . . . . . . . . . . . . . . 381
Tire Sidewall Labeling . . . . . . . . 381
Tire Designations . . . . . . . . . . . . . 383
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 385

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
332 Vehicle Care
Engine Compartment Overview
2.7L L4 Engine (L3B)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 339
1. Remote Negative (–) Location.See Jump Starting - North
America 0419.
2. Positive (+) Terminal (Under Cover). See Jump Starting -
North America 0419.
3. Battery - North America 0358.
4. Engine Air Cleaner/Filter 0344.
5. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil 0339.
6. Engine Cooling Fan (Out of View). See Cooling System
0 346.
7. Power Steering Fluid Reservoir. See Power Steering
Fluid 0354.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0339.
9. Auxiliary Battery. Battery -
North America 0358.
10. Brake Fluid Reservoir. See Brake Fluid 0357.
11. Engine Compartment Fuse
Block 0371. 12. Coolant Surge Tank and
Pressure Cap. See Cooling
System 0346.
13. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 354.
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
Engine Oil
For diesel engine vehicles, see
“Engine Oil” in the Duramax diesel
supplement.
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 0341.
. Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.Checking Engine Oil
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
0332 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
340 Vehicle Care
If a low oil Driver Information Center
(DIC) message displays, check the
oil level.
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
engine oil level on steep grades
or too soon after engine shutoff
can result in incorrect readings.
Accuracy improves when
checking a cold engine prior to
starting. Remove the dipstick
and check the level.
. If unable to wait two hours, the
engine must be off for at least
15 minutes if the engine is
warm, or at least 30 minutes if
the engine is not warm. Pull out
the dipstick, wipe it with a clean
paper towel or cloth, then push it
back in all the way. Remove it
again, keeping the tip down, and
check the level.When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick and
the engine has been off for at least
15 minutes, add 1 L (1 qt) of the
recommended oil and then recheck
the level. See “Selecting the Right
Engine Oil” later in this section for
an explanation of what kind of oil to
use. For engine oil crankcase
capacity, see Capacities and
Specifications 0459.
Caution
Do not add too much oil. Oil
levels above or below the
acceptable operating range
shown on the dipstick are harmful
to the engine. If the oil level is
(Continued)
Caution (Continued)
above the operating range (i.e.,
the engine has so much oil that
the oil level gets above the
cross-hatched area that shows
the proper operating range), the
engine could be damaged. Drain
the excess oil or limit driving of
the vehicle, and seek a service
professional to remove the
excess oil.
See Engine Compartment Overview
0 332 for the location of the engine
oil fill cap.
Add enough oil to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when through.
Selecting the Right Engine Oil
Selecting the right engine oil
depends on both the proper oil
specification and viscosity grade.
See Recommended Fluids and
Lubricants 0453.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
344 Vehicle Care
3. PressTon the steering wheel,
or press the trip odometer reset
stem if the vehicle does not
have DIC controls, to move to
the Reset/Disable display area.
Select Reset then press the
thumbwheel or press the reset
stem for several seconds.
4. Press the thumbwheel or the reset stem to confirm the reset.
Engine Air Cleaner/Filter
The engine air cleaner/filter is on
the driver side of the engine
compartment. See Engine
Compartment Overview 0332.
When to Inspect the Engine Air
Cleaner/Filter
If the vehicle is not equipped with
the engine air filter life system see
Maintenance Schedule 0442 for
intervals on inspecting and
replacing the engine air cleaner
filter.
How to Inspect/Replace the
Engine Air Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/
filter, make sure that the engine air
cleaner/filter housing and nearby
components are free of dirt and
debris. Do not clean the engine air
cleaner/filter or components with
water or compressed air.
To inspect or replace the engine air
cleaner/filter:
5.3L V8 Engine (L84) Shown, 2.7L
L4 Engine (L3B), 4.3L V6 Engine(LV3), 5.3L V8 Engine (L82), and
6.2L V8 Engine (L87) Similar
1. Air Duct Clamp
2. Electrical Harness Connector
3. Screws
1. Locate the air cleaner/filter assembly. See Engine
Compartment Overview 0332.
2. Disconnect the outlet duct by loosening the air duct
clamp (1).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 345
3. Disconnect the electricalharness connector (2) from the
cover.
4. Remove the three screws on top of the cover of the housing,
then slide and lift the cover.
5. Lift and remove the engine air cleaner/filter.
6. Lightly tap and shake the engine air cleaner/filter, away
from the vehicle, to release
loose dust and dirt. Replace
the engine air filter if damaged.
7. Reverse steps 2–5 to reinstall the engine air cleaner/filter
cover housing.
8. If equipped, reset the engine air filter life system after
replacing the engine air filter.
See Engine Air Filter Life
System 0343.
6.6L V8 Engine (L8T)
1. Locate the air cleaner/filter assembly. See Engine
Compartment Overview 0332.
2. Remove the eight screws on top of the cover of the housing,
then lift the cover.
3. Remove the engine air cleaner/ filter from the housing. Take
care to dislodge as little dirt as
possible.
4. Clean the engine air cleaner/ filter sealing surfaces and the
housing. 5. Inspect or replace the engine
air cleaner/filter.
6. Reverse Steps 2–4 to reinstall the filter cover housing.
7. If equipped, reset the engine air filter life system after
replacing the engine air filter.
see Engine Air Filter Life
System 0343.
{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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
348 Vehicle Care
Caution
Do not use anything other than a
mix of DEX-COOL coolant that
meets GM Standard
GMW3420 and clean, drinkable
water. Anything else can cause
damage to the engine cooling
system and the vehicle, which
would not be covered by the
vehicle warranty.
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.
Checking Coolant
The coolant surge tank is in the
engine compartment on the driver
side of the vehicle. See Engine
Compartment Overview 0332.
The vehicle must be on a level
surface when checking the coolant
level.
All Engines Except 6.6L V8 (L8T) Engine
6.6L V8 (L8T) Engine Only
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 indicated 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 indicated
mark, see the following sections on
how to add coolant to the coolant
surge tank following.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
354 Vehicle Care
Power Steering Fluid
The power steering fluid reservoir is
in the engine compartment on the
driver side of the vehicle. See
Engine Compartment Overview
0332 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
How to Check Power Steering
Fluid
To check the power steering fluid:
1. Set the ignition off and let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the
dipstick.
The level should be between the
ADD and FULL marks. If necessary,
add only enough fluid to bring the
level up to the hashed area between
the ADD and FULL marks.
To prevent contamination of brake
fluid, never check or fill the power
steering reservoir with the brake
master cylinder cover off.
What to Use
Caution
Use of the incorrect fluid may
damage the vehicle and the
damages may not be covered by
the vehicle warranty. Always use
the correct fluid listed in
Recommended Fluids and
Lubricants0453.
To determine what kind of fluid to
use, see Recommended Fluids and
Lubricants 0453. Always use the
proper fluid. Failure to use the
proper fluid can cause leaks and
damage hoses and seals.
Washer Fluid
What to Use
When windshield washer fluid needs
to be added, be sure to read the
manufacturer's instructions before
use. Use a fluid that has sufficient
protection against freezing in an
area where the temperature may fall
below freezing.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 355
Adding Washer Fluid
The vehicle has a low washer fluid
message on the DIC that comes on
when the washer fluid is low. The
message is displayed for
15 seconds at the start of each
ignition cycle. When the WASHER
FLUID LOW ADD FLUID message
displays, washer fluid will need to
be added to the windshield washer
fluid reservoir.
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. SeeEngine
Compartment Overview 0332 for
reservoir location.
Caution
. Do not use washer fluid that
contains any type of water
repellent coating. This can
cause the wiper blades to
chatter or skip.
. Do not use engine coolant
(antifreeze) in the
windshield washer. It can
damage the windshield
washer system and paint.
. Do not mix water with
ready-to-use washer fluid.
Water can cause the
solution to freeze and
damage the washer fluid
tank and other parts of the
washer system.
. When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
. Fill the washer fluid tank
only three-quarters full when
it is very cold. This allows
(Continued)
Caution (Continued)
for fluid expansion if
freezing occurs, which could
damage the tank if it is
completely full.
Brakes
Disc brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 357
level DIC. Repeat for pads on
the other axle if they were also
replaced.
How to Disable the Brake Pad
Life System
The brake pad life system can be
turned off. This may be necessary if
aftermarket brake pads without wear
sensors are installed. When the
system is turned off, the front and
rear brake pad life percentages will
not display. However, the built-in
wear indicators that make a
high-pitched warning sound when
the brake pads are worn can still
determine when the pads should be
replaced. SeeBrakes0355.
To turn off the brake pad life system: 1. Display Brake Pad Life on the DIC. See Driver Information
Center (DIC) (Base Level)
0 148 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0149.
2. Select DISABLE. To turn the brake pad life system
back on, follow the above steps but
select ENABLE in Step 2.
Brake Fluid
The brake master cylinder reservoir
is filled with GM approved DOT 4
(1500) or DOT 3 (2500/3500) brake
fluid as indicated on the reservoir
cap. See
Engine Compartment
Overview 0332 for the location of
the reservoir.
Checking Brake Fluid
With the vehicle in P (Park) on a
level surface, the brake fluid level
should be between the minimum
and maximum marks on the brake
fluid reservoir.
There are only two reasons why the
brake fluid level in the reservoir may
go down: .
Normal brake lining wear. When
new linings are installed, the
fluid level goes back up.
. A fluid leak in the brake
hydraulic system. Have the
brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid
reservoir cap and the area around
the cap before removing it.
Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings are
worn, there will be too much fluid
when new brake linings are
installed. Add or remove fluid, as
necessary, only when work is done
on the brake hydraulic system.
{Warning
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged. (Continued)