2024 GMC SIERRA DENALI engine overheat

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 319
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.
{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.
1. Engine Cooling Fan (Out of View)
2. Coolant Surge Tank and Pressure Cap
{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 0321.
What to Use
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
320 Vehicle Care
.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
0 313. The vehicle must be on a level surface when
checking the coolant level.
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.
How to Add Coolant to the Coolant
Surge Tank
If the vehicle has a diesel engine, see
“Cooling System”
in the Duramax diesel
supplement for the proper coolant fill
procedure.
{Warning
Spilling coolant on hot engine parts can
burn you. Coolant contains ethylene
glycol and it will burn if the engine parts
are hot enough.
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 321
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
Caution
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
If no coolant is visible in the surge tank, add
coolant.
1. Remove the coolant surge tank pressure cap when the cooling system, including
the coolant surge tank pressure cap and
upper radiator hose, is no longer hot.
Turn the pressure cap slowly
counterclockwise about one full turn. If a
hiss is heard, wait for that to stop.
A hiss means there is still some
pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper mixture to the full cold mark.
4. With the coolant surge tank pressure cap off, start the engine and let it run until
the engine coolant temperature gauge
indicates approximately 90 °C (195 °F).
By this time, the coolant level inside the
coolant surge tank may be lower. If the
level is lower, add more of the proper
mixture to the coolant surge tank until
the level reaches the indicated mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1–6.Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Engine Overheating
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
Caution
Do not run the engine if there is a leak
in the engine cooling system. This can
cause a loss of all coolant and can
damage the system and vehicle. Have
any leaks fixed right away.
The vehicle has several indicators to warn of
engine overheating.
There is a coolant temperature gauge in the
vehicle's instrument cluster. See Engine
Coolant Temperature Gauge 0118.
In addition, there are ENGINE OVERHEATED
STOP ENGINE, ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS REDUCED
messages in the Driver Information
Center (DIC).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
322 Vehicle Care
If the decision is made not to lift the hood
when this warning appears, get service help
right away. SeeRoadside Assistance Program
0 408.
If the decision is made to lift the hood,
make sure the vehicle is parked on a level
surface.
Check to see if the engine cooling fans are
running. If the engine is overheating, the
fans should be running. If they are not, do
not continue to run the engine and have the
vehicle serviced.
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 operation
may continue unless the display indicates
there is a hot condition and engine should
be idled.If Steam is Coming from the Engine
Compartment
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
If No Steam is Coming from the Engine
Compartment
The ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious problem.
If there is an engine overheat warning, but
no steam is seen or heard, the problem may
not be too serious. Sometimes the engine
can get a little too hot when the vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
.Tows a trailer; see Trailer Towing0280.
If the ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE
message appears with no sign of steam, try
this for a minute or so: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan
speed. Open the windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and
let the engine idle.
If the temperature overheat gauge is no
longer in the overheat zone or an overheat
warning no longer displays, the vehicle can
be driven. Continue to drive the vehicle
slowly for about 10 minutes. Keep a safe
vehicle distance from the vehicle in front.
If the warning does not come back on,
continue to drive normally and have the
cooling system checked for proper fill and
function.
If the warning continues, pull over, stop, and
park the vehicle right away.
If there is still no sign of steam and the
vehicle is equipped with an engine driven
cooling fan, push down the accelerator until
the engine speed is about twice as fast as

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 323
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
0314.
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 0313 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-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 337
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 0310 and
General Information 0310.
To check or replace a blown fuse, see
Electrical System Overload 0335.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
350 Vehicle Care
Tire Pressure
Tires need the correct amount of air
pressure to operate effectively.
{Warning
Neither tire underinflation nor
overinflation is good. Underinflated
tires, or tires that do not have
enough air, can result in:
.Tire overloading and overheating,
which could lead to a blowout
.Premature or irregular wear
.Poor handling
.Reduced fuel economy for
internal combustion engine
vehicles
.Reduced range for electric vehicles
Overinflated tires, or tires that have
too much air, can result in:
.Unusual wear
.Poor handling
.Rough ride
(Continued)
Warning (Continued)
.Needless damage from road
hazards
The Tire and Loading Information label
on the vehicle indicates the original
equipment tires and the correct cold
tire inflation pressures. The
recommended pressure is the minimum
air pressure needed to support the
vehicle's maximum load carrying
capacity.
For additional information regarding
how much weight the vehicle can carry,
and an example of the Tire and Loading
Information label, see Vehicle Load
Limits 0210. How the vehicle is loaded
affects vehicle handling and ride
comfort. Never load the vehicle with
more weight than it was designed to
carry.
When to Check
Check the pressure of the tires once a
month or more. Do not forget the spare, if the vehicle
has one. See
Full-Size Spare Tire 0375
for additional information.
How to Check
Use a good quality pocket-type gauge
to check tire pressure. Proper tire
inflation cannot be determined by
looking at the tire. Check the tire
inflation pressure when the tires are
cold, meaning the vehicle has not been
driven for at least three hours or no
more than 1.6 km (1 mi).
Remove the valve cap from the tire
valve stem. Press the tire gauge firmly
onto the valve to get a pressure
measurement. If the cold tire inflation
pressure matches the recommended
pressure on the Tire and Loading
Information label, no further adjustment
is necessary. If the inflation pressure is
low, add air until the recommended
pressure is reached. If the inflation
pressure is high, press on the metal
stem in the center of the tire valve to
release air.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
428 Index
Data Collection (cont'd)OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
Data Recorders, Event . . . . . . . . . . . . . . . . . . . .415
Daytime Running Lamps (DRL) . . . . . . . . . . . .145
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . . . 200
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Diagnostics Connected Services . . . . . . . . . . . . . . . . . . . . 424
Disabled Vehicle Transporting . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
Distracted
Driving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . . . 199
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 23
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Drive Belt Routing, Engine . . . . . . . . . . . . . . . 404
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 329
Driver Assistance Systems, Advanced . . . . . . . . . 252
Information Center (DIC) . . . . . . . . . . . 131, 133
Mode Control . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Mode Control Light . . . . . . . . . . . . . . . . . . . . 128 Driver (cont'd)
Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Driving Assistance Systems . . . . . . . . . . . . . . . . . . . . 263
Better Fuel Economy . . . . . . . . . . . . . . . . . . . 199
Characteristics and Towing Tips . . . . . . . . 276
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Hill and Mountain Roads . . . . . . . . . . . . . . 207
If the Vehicle is Stuck . . . . . . . . . . . . . . . . . 209
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 202
Off-Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 202
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 210
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
Dual Automatic Climate Control System . . . . 193
E
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . . . 272
ElectricParking Brake . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Parking Brake Light . . . . . . . . . . . . . . . . . . . . 124
Electrical Equipment, Add-On . . . . . . . . . . . . . . . . . . . . 306
System Overload . . . . . . . . . . . . . . . . . . . . . . 335 Electrical System
Engine Compartment Fuse Block . . . . . . . 337
Fuses and Circuit Breakers . . . . . . . . . . . . . 337
Instrument Panel Fuse Block . . . . . . 341, 342
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Emergency
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . 318
Air Filter Life System . . . . . . . . . . . . . . . . . . . 317
Check Light (Malfunction Indicator) . . . . 122
Compartment Overview . . . . . . . . . . . . . . . . 313
Coolant Temperature Gauge . . . . . . . . . . . . 118
Coolant Temperature WarningLight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 319
Drive Belt Routing . . . . . . . . . . . . . . . . . . . . . 404
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 316
Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . . 117
Oil Pressure Light . . . . . . . . . . . . . . . . . . . . . . 129
Overheated Protection Operating Mode . . . . . . . . . . . . . . . . . . . . . 323
Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Power Messages . . . . . . . . . . . . . . . . . . . . . . . 139