2021 GMC SIERRA engine coolant

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 121
serviced by your dealer. If the system is
working normally, the indicator light then
turns off. This light comes on when the
Electronic Stability Control (ESC) system is
turned off. If ESC is off, the Traction Control
System (TCS) is also off. To turn ESC off and
on, seeTraction Control/Electronic Stability
Control 0248.
If ESC and TCS are off, the systems do not
assist in controlling the vehicle. Adjust
driving accordingly.
Engine Coolant Temperature
Warning Light
This light comes on briefly while starting
the vehicle.
If it does not, have the vehicle serviced by
your dealer. If the system is working
normally the indicator light goes off.
Caution
The engine coolant temperature warning
light indicates that the vehicle has
overheated. Driving with this light on can
damage the engine and it may not be
covered by the vehicle warranty. See
Engine Overheating 0338.
The engine coolant temperature warning
light comes on when the engine has
overheated.
If this happens, pull over and turn off the
engine as soon as possible. See Engine
Overheating 0338.
Driver Mode Control Light
This light comes on when Sport Mode is
selected.
This light comes on when Snow/Ice Mode is
selected.
This light comes on when Terrain Mode is
selected.
This light comes on when Off-Road Mode is
selected.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 291
Driving on Grades
Reduce speed and shift to a lower gear
before starting down a long or steep
downhill grade. If the transmission is not
shifted down, the brakes may overheat and
result in reduced braking efficiency.
The vehicle can tow in D (Drive). Shift the
transmission to a lower gear if the
transmission shifts too often under heavy
loads and/or hilly conditions.
When towing at higher altitudes, engine
coolant will boil at a lower temperature
than at lower altitudes. If the engine is
turned off immediately after towing at high
altitude on steep uphill grades, the vehicle
could show signs similar to engine
overheating. To avoid this, let the engine
run, 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 0338.
Viewing Systems
If equipped, the viewing systems on the
vehicle can improve visibility while hitching,
backing, and driving with a trailer. See
Driver Assistance Systems 0265.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer on a
level surface when possible.
When parking your vehicle and your trailer
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. Gradually release the brake pedal to allow the chocks to absorb the load of
the trailer.
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.
.Start the engine.
.Shift into a gear.
.Release the parking brake. 2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of
the chocks.
4. Stop and have someone pick up and store the chocks.
Launching and Retrieving a Boat
Backing the Trailer into the Water
{Warning
.Have all passengers get out of the
vehicle before backing onto the sloped
part of the ramp. Lower the driver and
passenger side windows before
backing onto the ramp. This will
provide a means of escape in the
unlikely event the vehicle slides into
the water.
.If the boat launch surface is slippery,
have the driver remain in the vehicle
with the brake pedal applied while the
boat is being launched. The boat
launch can be especially slippery at
low tide when part of the ramp was
previously submerged at high tide. Do
not back onto the ramp to launch the
boat if you are not sure the vehicle
can maintain traction.
(Continued)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 319
Caution (Continued)
one to the vehicle. If the vehicle has RPO
VYU, then the payload the vehicle can
carry will be reduced when a snow plow
is installed. The vehicle can be damaged
if either the front or rear axle ratings or
the Gross Vehicle Weight Rating (GVWR)
are exceeded.
The plow the vehicle can carry depends on
many things, such as:
.The options the vehicle came with, and
the weight of those options.
.The weight and number of passengers to
be carried.
.The weight of items added to the vehicle,
like a tool box or truck cap.
.The total weight of any additional cargo
to be carried.
To safely carry a snow plow on the vehicle:
.With a snow plow attached, the engine
coolant temperature gauge may show a
higher temperature than while driving
without one. The snow plow could block
the airflow to the radiator. This could be
more noticeable as vehicle speed
increases. At speeds above 72 km/h
(45 mph), this may cause the engine coolant to overheat. Move or angle the
snow plow blade to allow increased
airflow to the radiator.
.To increase the airflow, move the snow
plow blade position.
.If driving more than 24 km/h (15 mi),
angle the plow blade position.
.Make sure the weight on the front and
rear axles does not exceed the axle rating
for each.
.Follow the snowplow manufacturer’s
recommendations for any rear ballast that
may be required. Rear ballast may be
required to ensure a proper front and rear
weight distribution ratio even though the
actual weight at the front axle may be
less than the front axel rating.
.The snowplow manufacturer or installer
can assist in determining the amount of
rear ballast required to ensure that the
vehicle with the attached snowplow does
not exceed the GVW rating, the front and
rear axle ratings, or the front and rear
weight distribution ratio.
Front axle reserve capacity is the difference
between the Front Gross Axle Weight
Rating (GAWR) and the front axle weight of
the vehicle with full fuel, passengers, and any other cargo. This is the amount of
weight that can be added to the front axle
before reaching the Front GAWR.
To calculate the amount of weight any front
accessory, such as a snow plow, is adding to
the front axle, use this formula:
(W x (A + W.B.)) /W.B.= Weight the accessory
is adding to the front axle.
Where:
IW = Weight of added accessory
IA = Distance that the accessory is in
front of the front axle
IW.B. = Vehicle Wheelbase

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
326 Vehicle Care
1. Remote Negative (–) Location. SeeJump
Starting - North America 0391.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0391.
3. Battery - North America 0343.
4. Engine Compartment Fuse Block 0353.
5. Engine Cooling Fans (Out of View). See Cooling System 0335.
6. Engine Oil Fill Cap. See “When to Add
Engine Oil” underEngine Oil 0330.
7. Engine Oil Dipstick. See “Checking Engine
Oil” under Engine Oil 0330.
8. Coolant Surge Tank and Pressure Cap. See Cooling System 0335.
9. Engine Air Cleaner/Filter 0334.
10. Brake Fluid Reservoir. See Brake Fluid
0 343.
11. Windshield Washer Fluid Reservoir. See “Adding Washer Fluid” underWasher
Fluid 0340.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
328 Vehicle Care
1. Remote Negative (–) Location. SeeJump
Starting - North America 0391.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0391.
3. Battery - North America 0343.
4. Engine Compartment Fuse Block 0353.
5. Engine Cooling Fans (Out of View). See Cooling System 0335.
6. Engine Oil Dipstick. See “Checking Engine
Oil” under Engine Oil 0330.
7. Engine Oil Fill Cap. See “When to Add
Engine Oil” underEngine Oil 0330.
8. Coolant Surge Tank and Pressure Cap. See Cooling System 0335.
9. Engine Air Cleaner/Filter 0334.
10. Brake Fluid Reservoir. See Brake Fluid
0 343.
11. Windshield Washer Fluid Reservoir. See “Adding Washer Fluid” underWasher
Fluid 0340.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
330 Vehicle Care
1. Remote Negative (–) Location. SeeJump
Starting - North America 0391.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0391.
3. Battery - North America 0343.
4. Engine Compartment Fuse Block 0353.
5. Engine Oil Dipstick. See “Checking Engine
Oil” under Engine Oil 0330.
6. Engine Cooling Fans (Out of View). See Cooling System 0335.
7. Engine Oil Fill Cap. See “When to Add
Engine Oil” underEngine Oil 0330.
8. Coolant Surge Tank and Pressure Cap. See Cooling System 0335.
9. Engine Air Cleaner/Filter 0334.
10. Brake Fluid Reservoir. See Brake Fluid
0 343.
11. Windshield Washer Fluid Reservoir. See “Adding Washer Fluid” underWasher
Fluid 0340.
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. SeeEngine Oil Life System 0332.
.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 0325 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.
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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 335
{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
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
The cooling system allows the engine to
maintain the correct working temperature.
2.7L L4 Engine (L3B)
4.3L V6 Engine (LV3)
5.3L V8 Engine (L84) Shown, 5.3L V8 Engine(L82) and 6.2L V8 Engine (L87) Similar
1. Engine Electric Cooling Fans (Out of View)
2. Coolant Surge Tank and Pressure Cap
{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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
336 Vehicle Care
{Warning
Do not touch heater, radiator, a/c pipes
or 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, seeEngine Overheating 0338.
What to Use
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
(Continued)
Warning (Continued)
the wrong mixture, the engine could get
too hot but there would not be an
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. 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
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
0 325.
The vehicle must be on a level surface when
checking the coolant level.
All Engines