2023 GMC SIERRA engine

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 315
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.
If there is no sign of steam, idle the engine
for five minutes while parked. If the warning
is still displayed, turn off the engine until it
cools down.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and
the ENGINE POWER IS REDUCED message
displays, an overheat protection mode which
alternates firing groups of cylinders helps to
prevent engine damage. In this mode, a loss
in power and engine performance will be
noticed. This operating mode allows the
vehicle to be driven to a safe place in an
emergency. Driving extended distances and/
or towing a trailer in the overheat
protection mode should be avoided.
If the engine or transmission detects an
impending hot fluid condition, then the
transmission may force upshifts to limit
temperatures. Downshifts may also be
prevented in this instance. Normal operationmay continue unless the display indicates
there is a hot condition and engine should
be idled.
Caution
After driving in the overheated engine
protection operating mode, the engine oil
will be severely degraded. Any repairs
performed before the engine is cool may
cause engine damage. Allow the engine
to cool before attempting any repair.
Repair the cause of coolant loss, change
the oil, and reset the oil life system. See
Engine Oil
0306.
Engine Fan
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
The vehicle has a clutched engine cooling
fan. When the clutch is engaged, the fan
spins faster to provide more air to cool the
engine. In most everyday driving conditions,
the fan is spinning slower and the clutch is
not fully engaged. This improves fuel
economy and reduces fan noise. Under
heavy vehicle loading, trailer towing, and/or
high outside temperatures, the fan speed
increases as the clutch more fully engages, so an increase in fan noise may be heard.
This is normal and should not be mistaken
as the transmission slipping or making extra
shifts. It is merely the cooling system
functioning properly. The fan will slow down
when additional cooling is not required and
the clutch partially disengages.
This fan noise may be heard when starting
the engine. It will go away as the fan clutch
partially disengages.
Power Steering Fluid
The power steering fluid reservoir is in the
engine compartment on the driver side of
the vehicle. See
Engine Compartment
Overview 0305 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

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
316 Vehicle Care
is heard. A fluid loss in this system could
indicate a problem. Have the system
inspected and repaired.
Wait for the power steering system to cool,
with the engine off, before checking the
fluid.
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, do
not overfill. 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 Lubricants
0389.
To determine what kind of fluid to use, see
Recommended Fluids and Lubricants 0389.
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.
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. See
Engine Compartment Overview 0305 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.
(Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 317
Caution (Continued)
.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 for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake linings have built-in wear
indicators that make a high-pitched warning
sound when the brake linings are worn and
new linings are needed. The sound can come
and go or can be heard all the time when
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.
Caution
Continuing to drive with worn-out brake
linings could result in costly brake
repairs.
Some driving conditions or climates can
cause a brake squeal when the brakes are
first applied, clearing up following several
applications. This does not mean something
is wrong with the brakes.
Properly torqued wheel nuts are necessary
to help prevent brake pulsation. When tires
are rotated, inspect brake linings for wear
and evenly tighten wheel nuts in the proper
sequence to torque specifications. See
Capacities and Specifications 0393.
Brake pads should be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer if the brake pedal does not
return to normal height, or if there is a
rapid increase in pedal travel. This could be
a sign that brake service may be required.
Replacing Brake System Parts
Always replace brake system parts with
new, approved replacement parts. If this is
not done, the brakes may not work
properly. The braking performance can
change in many ways if the wrong brake
parts are installed or if parts are improperly
installed.
Brake Pad Life System
When to Change Brake Pads
This vehicle has a system that estimates the
remaining life of the front and rear brake
pads. Brake pad life is displayed in the
Driver Information Center (DIC), along with
a percentage for each axle. The system must
be reset every time the brake pads are
changed.
When the system has determined that the
brake pads need to be replaced, a message
will display, which may include mileage
remaining.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
318 Vehicle Care
Brake pads should always be replaced as
complete axle sets.
How to Reset the Brake Pad Life System
The system will automatically detect when
significantly worn brake pads are replaced.
When the ignition is turned on after new
pads and wear sensors are installed, a
message will display. Follow the prompts to
reset the system.
The brake pad life system can also be
manually reset:1. Display Brake Pad Life on the DIC. See Driver Information Center (DIC) (Base
Level) 0128 or
Driver Information Center (DIC) (Midlevel
and Uplevel) 0130.
2. Select the Brake Pad Life menu.
3. Select front or rear pads as appropriate.
4. Select YES on the confirmation message. 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. See
Brakes0317.
To turn off the brake pad life system: 1. Display Brake Pad Life on the DIC. See Driver Information Center (DIC) (Base
Level) 0128 or
Driver Information Center (DIC) (Midlevel
and Uplevel) 0130.
2. Select the Brake Pad Life menu.
3. 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 brake fluid as
indicated on the reservoir cap. See Engine
Compartment Overview 0305 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

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 319
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. Add brake fluid only when
work is done on the brake hydraulic
system.
When the brake fluid falls to a low level,
the brake warning light comes on. See Brake
System Warning Light 0122.
Brake fluid absorbs water over time which
degrades the effectiveness of the brake fluid.
Replace brake fluid at the specified intervals
to prevent increased stopping distance. See
Maintenance Schedule 0385.
What to Add
Use only GM approved DOT 4 brake fluid
from a clean, sealed container. See
Recommended Fluids and Lubricants 0389.
{Warning
The wrong or contaminated brake fluid
could result in damage to the brake
system. This could result in the loss of
braking leading to a possible injury.
Always use the proper GM approved
brake fluid.
Caution
If brake fluid is spilled on the vehicle's
painted surfaces, the paint finish can be
damaged. Immediately wash off any
painted surface.
Battery - North America
The original equipment battery is
maintenance free. Do not remove the cap
and do not add fluid.
Refer to the replacement number shown on
the original battery label when a new
battery is needed. See Engine Compartment
Overview 0305 for battery location.
{Warning
WARNING: Battery posts, terminals and
related accessories can expose you to
chemicals including lead and lead
compounds, which are known to the
State of California to cause cancer and
birth defects or other reproductive harm.
Wash hands after handling. For more
information go to
www.P65Warnings.ca.gov.
See California Proposition 65 Warning 01.
Vehicle Storage
{Warning
Batteries have acid that can burn you and
gas that can explode. You can be badly
hurt if you are not careful. See Jump
Starting - North America 0367 for tips on
working around a battery without
getting hurt.
Infrequent Usage: Remove the black,
negative (−) cable from the battery to keep
the battery from running down.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
322 Vehicle Care
General Motors LLC, and is not limited to
any particular part, component or system of
the vehicle manufactured by General Motors
LLC. Defects in design, assembly or in any
part, component or system of the vehicle as
manufactured by General Motors LLC, which,
at the time it left General Motors LLC’s
control, caused noise emissions to exceed
Federal standards, are covered by this
warranty for the life of the vehicle.
TAMPERING WITH NOISE CONTROL
SYSTEM PROHIBITED
Federal law prohibits the following acts or
the causing thereof:1. The removal or rendering inoperative by any person, other than for purposes of
maintenance, repair, or replacement, of
any device or element of design
incorporated into any new vehicle for
the purpose of noise control prior to its
sale or delivery to the ultimate purchaser
or while it is in use; or
2. the use of the vehicle after such device or element of design has been removed
or rendered inoperative by any person. Among those acts presumed to constitute
tampering are the acts listed below.
Insulation:
Removal of the noise shields or any
undercab insulation.
Engine:
Removal or rendering engine speed
governor, if so equipped, inoperative so as
to allow engine speed to exceed
manufacturer specifications.
Modification of the engine control system or
calibration.
Fan and Drive:
.Removal of fan clutch or rendering clutch
inoperative.
.Removal of the fan shroud.
Air Intake:
.Removal of air cleaner silencer.
.Reversing air cleaner cover.
Exhaust:
.Removal of muffler, catalytic converter,
and/or resonator.
.Removal of exhaust pipes and exhaust
pipe clamps.
Automatic Transmission Shift Lock
Control Function Check
(Mechanical Shifter)
{Warning
When you are doing this inspection, the
vehicle could move suddenly. If the
vehicle moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room around the vehicle.
It should be parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular brake immediately if
the vehicle begins to move.
3. With the engine off, turn the ignition on, but do not start the engine. Without
applying the regular brake, try to move
the shift lever out of P (Park) with
normal effort. If the shift lever moves
out of P (Park), contact your dealer for
service.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 323
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check, the
vehicle could begin to move. You or
others could be injured and property
could be damaged. Make sure there is
room in front of the vehicle in case it
begins to roll. Be ready to apply the
regular brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the vehicle
facing downhill. Keeping your foot on the
regular brake, set the parking brake.
.To check the parking brake's holding
ability: With the engine running and the
transmission in N (Neutral), slowly remove
foot pressure from the regular brake
pedal. Do this until the vehicle is held by
the parking brake only.
.To check the P (Park) mechanism's holding
ability: With the engine running, shift to
P (Park). Then release the parking brake
followed by the regular brake.
Contact your dealer if service is required.
Wiper Blade Replacement
Windshield wiper blades should be replaced
periodically. See Maintenance Schedule
0 385.
Replacement blades come in different types
and are removed in different ways. For
proper type and length, see Maintenance
Replacement Parts 0390.
Caution
Allowing the wiper arm to touch the
windshield when no wiper blade is
installed could damage the windshield.
Any damage that occurs would not be
covered by the vehicle warranty. Do not
allow the wiper arm to touch the
windshield.
Front Wiper Blade Replacement
To replace the wiper blade:
1. Pull the wiper assembly away from the windshield.
2. Lift up on the latch in the middle of the
wiper blade where the wiper arm
attaches.
3. With the latch open, pull the wiper blade down toward the windshield far enough
to release it from the J-hooked end of
the wiper arm.
4. Remove the wiper blade.
5. Reverse Steps 1–3 for wiper blade replacement.
Glass Replacement
If the windshield or front side glass must be
replaced, see your dealer to determine the
correct replacement glass.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 329
4. If the fuse must be replacedimmediately, spare fuses are also
provided on the instrument panel end
cap or borrow a replacement fuse with
the same amperage from the fuse block.
Choose a vehicle feature that is not
needed to safely operate the vehicle.
Repeat Steps 2-3.
5. Insert the replacement fuse into the empty slot of the blown fuse.
At the next opportunity, see your dealer to
replace the blown fuse.
Headlamp Wiring
An electrical overload may cause the lamps
to go on and off, or in some cases to
remain off. Have the headlamp wiring
checked right away if the lamps go on and
off or remain off.
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 and Circuit Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit breakers.
This greatly reduces the chance of damage
caused by electrical problems.
{Danger
Fuses and circuit breakers are marked
with their ampere rating. Do not exceed
the specified amperage rating when
replacing fuses and circuit breakers. Use
of an oversized fuse or circuit breaker can
result in a vehicle fire. You and others
could be seriously injured or killed.
{Warning
Installation or use of fuses that do not
meet GM’s original fuse specifications is
dangerous. The fuses could fail, and result
in a fire. You or others could be injured
or killed, and the vehicle could be
damaged.
See Accessories and Modifications 0302 and
General Information 0302.
To check or replace a blown fuse, see
Electrical System Overload 0327.
Engine Compartment Fuse Block
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
The engine compartment fuse block is in the
engine compartment, on the driver side of
vehicle.