
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 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 339
FusesUsage
6 –
7 ELM 4 –Electronic
Lighting Module 4
8 –
9 –
10 ELM 6 –Electronic
Lighting Module 6
11 BCM 3 –Body Control
Module 3
12 Rear Window Defogger
13 Washer Front
14 –
15 –
16 –
17 IECL 1
19 DC/AC Inverter
20 IECR 2 (LD)/EBCM2 (HD) 21 –
22 IECL 2
24 Fuel Heater (DSL) Fuses
Usage
25 EBCM 1 –Electronic
Brake Control Module 1
26 –
27 Horn
28 Parking Lamp Mirror/ Grill (LD)/Parking Lamp
Left (HD)
29 Parking Lamp Right (HD)
30 ELM 3 –Electronic
Lighting Module 3
31 ELM 1 –Electronic
Lighting Module 1
32 –
33 Not R/C
34 Radars (LD) 37 MISC IP Headliner Ignition
38 Seat Fan Ignition
39 Trailer Ignition Module
40 Misc Ignition 41 Trailer Parking Lamp Fuses
Usage
42 Tail Lamp Left (HD)
44 DEFC/ICCM Ignition (LD/ HD)/FTZM Ignition (HD)
45 Secondary Axle Motor
46 Engine Control Module Ignition
47 –
48 –
49 Transmission Auxiliary Oil Pump (LD)
50 A/C Clutch 51 Transfer Case Control Module
52 Front Wiper
53 Center High-Mounted Stop Lamp
54 Tail Lamp Right (HD) 55 Trailer Back-up Lamp
56 SADS (LD)/Fuel Tank Zone Module 2 (HD)
57 TTPM/SBZA
58 Starter Motor (LD)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
386 Vehicle Care
.Promptly rinse the bed surface following
a chemical spill to avoid permanent
damage.
.Use a dry rag to remove oil.
Cleaning Exterior Lamps/Lenses,
Emblems, Decals and Stripes
Use only lukewarm or cold water, a soft
cloth, and a car washing soap to clean
exterior lamps, lenses, emblems, decals and
stripes. Follow instructions under "Washing
the Vehicle" previously in this section.
Lamp covers are made of plastic, and some
have a UV protective coating. Do not clean
or wipe them while they are dry.
Do not use any of the following on lamp
covers:
.Abrasive or caustic agents.
.Washer fluids and other cleaning agents
in higher concentrations than suggested
by the manufacturer.
.Solvents, alcohols, fuels, or other harsh
cleaners.
.Ice scrapers or other hard items.
.Aftermarket appearance caps or covers
while the lamps are illuminated, due to
excessive heat generated.
Caution
Failure to clean lamps properly can cause
damage to the lamp cover that would
not be covered by the vehicle warranty.
Caution
Using wax on low gloss black finish
stripes can increase the gloss level and
create a non-uniform finish. Clean low
gloss stripes with soap and water only.
Air Intakes
Clear debris from the air intakes, between
the hood and windshield, when washing the
vehicle.
Shutter System
The vehicle may have a shutter system
designed to help improve fuel economy.
Keep the shutter system clear of debris,
snow and ice. If the check engine light is
activated, please check to see if the shutter
system is clear of debris, snow or ice.
Windshield and Wiper Blades
Clean the outside of the windshield with
glass cleaner.
Clean rubber blades using a lint-free cloth or
paper towel soaked with windshield washer
fluid or a mild detergent. Wash the
windshield thoroughly when cleaning the

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
388 Vehicle Care
Inspect power steering for proper
attachment, connections, binding, cracks,
chafing, etc.
Visually check constant velocity joint boots
and axle seals for leaks.
2500/3500 Series vehicles, at least every
engine oil change lubricate the upper and
lower control arm ball joints.
2500/3500 Series vehicles equipped with
steering linkage, at least every engine oil
change lubricate the tie rod ball joints, idler
arm pivot shaft bearings, idler arm socket,
and pitman arm socket.
Caution
Lubrication of applicable suspension
points should not be done unless the
temperature is−12 °C (10 °F) or higher,
or damage could result.
Body Component Lubrication
Lubricate all key lock cylinders, hood hinges,
liftgate hinges, and the steel fuel door hinge
unless the components are plastic. Applying
silicone grease on weatherstrips with a clean
cloth will make them last longer, seal better,
and not stick or squeak.
Underbody Maintenance
At least twice a year, spring and fall, use
plain water to flush any corrosive materials
from the underbody. Take care to
thoroughly clean any areas where mud and
other debris can collect. If equipped with
power assist steps, extend them and then
use a high pressure wash to clean all joints
and gaps.
Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or axles and should be replaced.
Sheet Metal Damage
If the vehicle is damaged and requires sheet
metal repair or replacement, make sure the
body repair shop applies anti-corrosion
material to parts repaired or replaced to
restore corrosion protection.
Original manufacturer replacement parts will
provide the corrosion protection while
maintaining the vehicle warranty.
Finish Damage
Quickly repair minor chips and scratches
with touch-up materials available from your
dealer to avoid corrosion. Larger areas of
finish damage can be corrected in your
dealer's body and paint shop.
Chemical Paint Spotting
Airborne pollutants can fall upon and attack
painted vehicle surfaces causing blotchy,
ring-shaped discolorations, and small,
irregular dark spots etched into the paint
surface. Refer to “Finish Care”previously in
this section.
Interior Care
To prevent dirt particle abrasions, regularly
clean the vehicle's interior. Before using
cleaners, read and follow all safety
instructions on the label. While cleaning the
interior, open the doors and windows to get
proper ventilation. Newspapers or dark
garments can transfer color to the vehicle’s
interior.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Service and Maintenance 395
Additional Required Services–Normal
Service
Every 12 000 km (7,500 mi)
.Check engine oil level and oil
life percentage. If needed, change engine
oil and filter, and reset oil life system. Or
when the CHANGE ENGINE OIL SOON
message displays, have the engine oil
and filter changed within the next
1 000 km/600 mi. If driven under the best
conditions, the engine oil life system may
not indicate the need for vehicle service
for up to a year. The engine oil and filter
must be changed at least once a year and
the oil life system must be reset. Your
trained dealer technician can perform this
work. If the engine oil life system is reset
accidentally, service the vehicle within
5 000 km/3,000 mi since the last service.
Reset the oil life system when the oil is
changed. See Engine Oil Life System
0 316.
.When the REPLACE AT NEXT OIL CHANGE
message displays, the engine air filter
should be replaced at the next engine oil
change. When the REPLACE ENGINE AIR
FILTER SOON message displays, the
engine air filter should be replaced at the
earliest convenience. Reset the engine air filter life system after the engine air filter
is replaced. See
Engine Air Filter Life
System 0317.
Every 36 000 km (22,500 mi)
.Replace passenger compartment air filter.
Or every 24 months, whichever comes
first. More frequent passenger
compartment air filter replacement may
be needed if driving in areas with heavy
traffic, poor air quality, high dust levels,
or environmental allergens. Passenger
compartment air filter replacement may
also be needed if there is reduced airflow,
window fogging, or odors. Your GM
dealer can help determine when to
replace the filter.
Every 80 500 km (50,000 mi)
.Change transfer case fluid, if equipped
with 4WD. Do not directly power wash
the transfer case and/or front/rear axle
output seals. High pressure water can
overcome the seals and contaminate the
transfer case fluid. Contaminated fluid will
decrease the life of the transfer case
and/or axles and should be replaced.
Every 156 000 km (97,500 mi)
.Replace spark plugs. Inspect spark plug
wires and/or boots. Every 161 000 km (100,000 mi)
.Replace hood and/or body lift support gas
struts. Or every 10 years, whichever
comes first. See
Gas Strut(s)0332.
Every 240 000 km (150,000 mi)
.Drain and fill engine cooling system. Or
every six years, whichever comes first.
See Cooling System 0319.
Severe Conditions Requiring More
Frequent Maintenance*
.Public service, military, or commercial use
vehicles to include the following:
‐ Ambulances, police cars, and
emergency rescue vehicles.
‐ Civilian vehicles such as light duty
pick-up trucks, SUVs, and passenger
cars that are used in military
applications.
‐ Recovery vehicles such as tow trucks
and flatbed single vehicle carriers or
any vehicle that is consistently used in
towing trailers or other loads.
‐ High use commercial vehicles such as
courier delivery vehicles, private
security patrol vehicles, or any vehicles
that operate on a 24-hour basis.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
396 Service and Maintenance
‐Any vehicle consistently operated in a
high sand or dust environment such as
those used on oil pipelines and similar
applications.
.Vehicles that are regularly used for short
trips of 6 km (4 mi) or less.
The oil life indicator will show you when
to change the oil and filter. Under severe
conditions the indicator may come on
before 12 000 km (7,500 mi).
* Footnote: Under extreme driving
conditions listed above, it may be
necessary to replace your spark plugs at
more frequent intervals. For further
assistance in determining the most
suitable service maintenance intervals for
your vehicle, please contact your
authorized GM Dealer.
Extreme service is for vehicles mainly
driven off-road in four-wheel drive or used
in farming, mining, forestry, or snow
plowing.
Additional Required Services –Severe
Service
Every 40 000 km (25,000 mi)
.Change transfer case fluid, if equipped
with 4WD. Do not directly power wash
the transfer case and/or front/rear axle
output seals. High pressure water can
overcome the seals and contaminate the
transfer case fluid. Contaminated fluid will
decrease the life of the transfer case
and/or axles and should be replaced.
Every 72 000 km (45,000 mi)
.Change automatic transmission fluid and
filter.
Owner Checks and Services
Every Five Years
.Replace brake fluid.
Every Seven Years
.Replace Air Conditioning Desiccant every
seven years. The air conditioning system
requires maintenance every seven years.
This service requires replacement of the
desiccant to help the longevity and
efficient operation of the air conditioning
system. This service can be complex. See
your dealer.
Multi-Point Vehicle
Inspection (MPVI)
A Multi Point Vehicle Inspection (MPVI)
completed by a GM dealer technician is a
maintenance assessment of your vehicle.
The benefit of the MPVI is to identify and
inform the customer of service items that
require immediate attention and those that
may require attention in the future.
The technician will perform the following
checks on your vehicle. For a complete list
of checks, inspections, and services, see your
dealer.
Some items may not apply to your vehicle
and/or region.
Diagnostics
.OnStar active, if equipped
.Service history/recall check
Engine Oil and Filter
.Engine oil
.Oil life monitor
‐ Reset oil life monitor
Exterior Lights
.Visual inspection

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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Service and Maintenance 397
Windshield and Wipers
.Visual inspection
Battery
.Battery visual inspection
.Battery test results
.Battery cables and connections
Systems, Fluids, and Visible Leak
Inspection
.Engine oil
.Transmission
.Drive axle
.Transfer case
.Engine cooling system
.Power steering, if equipped
.Fuel system
.Windshield washer fluid
Tire Inspection
.Tire pressure, tread depth, and wear
.Rotation, if applicable
.Alignment check, optional
.Reset tire pressure monitor
.Check tire sealant expiration date,
if equipped
.Check spare tire, if equipped
Brakes
.Check brake system
Visible and Functional Inspections
.Seat belt components
.Exhaust system
.Accelerator pedal
.Passenger compartment air filter,
if equipped
.Engine air filter
.Hoses
.Belts
.Shocks and struts
.Steering components
.Axle boots or driveshaft and u-joints
.Compartment lift struts, if equipped
.Floor mats secured, no interference with
pedals
.Horn
.Ignition lock, if equipped
.Starter switch
.Evaporative control system
Lubricate
.Chassis components
Special Application Services
.Vehicles with Dual Wheels: Check dual
wheel nut torque at 160, 1 600, and
10 000 km (100, 1,000, and 6,000 mi) of
driving. Repeat this service whenever a
tire/wheel is serviced or removed.
.Severe Commercial Use Vehicles Only:
Lubricate chassis components every oil
change.
.Have underbody flushing service
performed. See “Underbody Maintenance”
in Exterior Care 0383.