GMC SIERRA DENALI 2020 Owners Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
430 Vehicle Care
Automatic Car Wash
Caution
Some automatic car washes can
cause damage to the vehicle,
wheels and ground effects.
Automatic car washes are not
recommended, due to lack of
clearance for the undercarriage
and/or wide rear tires and wheels.
Caution
Automatic car washes can cause
damage to the vehicle, wheels,
ground effects, and convertible
top (if equipped).
Do not use automatic car washes
due to lack of clearance for the
undercarriage, wide rear tires,
and wheels.
If using an automatic car wash,
follow with the car wash
instructions. The windshield wiper
and rear window wiper, if equipped, must be turned off. Remove any
accessories that may be damaged
or interfere with the car wash
equipment.
See
Power Assist Steps 034 for
cleaning information.
Rinse the vehicle well, before
washing and after, to remove all
cleaning agents completely. If they
are allowed to dry on the surface,
they could stain.
Dry the finish with a soft, clean
chamois or an all-cotton towel to
avoid surface scratches and water
spotting.Finish Care
Application of aftermarket clearcoat
sealant/wax materials is not
recommended. If painted surfaces
are damaged, see your dealer to
have the damage assessed and
repaired. Foreign materials such as
calcium chloride and other salts, ice
melting agents, road oil and tar, tree
sap, bird droppings, chemicals from
industrial chimneys, etc., can
damage the vehicle's finish if they
remain on painted surfaces. Wash the vehicle as soon as possible.
If necessary, use non-abrasive
cleaners that are marked safe for
painted surfaces to remove foreign
matter.
Occasional hand waxing or mild
polishing should be done to remove
residue from the paint finish. See
your dealer for approved cleaning
products.
Do not apply waxes or polishes to
uncoated plastic, vinyl, rubber,
decals, simulated wood, or flat paint
as damage can occur.
Caution
Machine compounding or
aggressive polishing on a
basecoat/clearcoat paint finish
may damage it. Use only
non-abrasive waxes and polishes
that are made for a basecoat/
clearcoat paint finish on the
vehicle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 431
To keep the paint finish looking new,
keep the vehicle garaged or
covered whenever possible.
Protecting Exterior Bright Metal
Moldings
Caution
Failure to clean and protect the
bright metal moldings can result
in a hazy white finish or pitting.
This damage would not be
covered by the vehicle warranty.
The bright metal moldings on the
vehicle are aluminum, chrome or
stainless steel. To prevent damage
always follow these cleaning
instructions:
. Be sure the molding is cool to
the touch before applying any
cleaning solution.
. Use only approved cleaning
solutions for aluminum, chrome
or stainless steel. Some
cleaners are highly acidic or
contain alkaline substances and
can damage the moldings. .
Always dilute a concentrated
cleaner according to the
manufacturer ’s instructions.
. Do not use cleaners that are not
intended for automotive use.
. Use a nonabrasive wax on the
vehicle after washing to protect
and extend the molding finish.
Spray-In Bedliner Care
Caution
Using silicone-based products
may damage the bedliner, reduce
the slip-resistant texture, and
attract dirt.
A spray-in bedliner is a permanent
coating that bonds to the truck bed
and cannot be removed. Promptly
rinse the bedliner surface following
a chemical spill to avoid permanent
damage.
Spray-in bedliners can fade from
oxidation, road dirt, heavy-duty
hauling, and hard water stains.
Clean it periodically by washing off the loose dirt and using a mild
detergent. To restore the original
appearance, apply the bedliner
conditioner available through your
dealer.
CarbonPro Box Care
Caution
To prevent surface damage to the
pickup box, rinse chemical spills
quickly, never use alcohol wipes
to clean, and avoid scraping the
surface.
If equipped with a CarbonPro
Pickup Box, use the following
instructions for cleaning:
. Clean the box periodically by
washing off the loose dirt with
water and a mild detergent.
. Promptly rinse the bed surface
following a chemical spill to
avoid permanent damage.
. Use a dry rag to remove oil.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
432 Vehicle Care
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 increase
fuel economy. Keep the shutter
system clean for proper operation.
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
blades. Bugs, road grime, sap, and

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 433
a buildup of vehicle wash/wax
treatments may cause wiper
streaking.
Replace the wiper blades if they are
worn or damaged. Damage can be
caused by extreme dusty
conditions, sand, salt, heat, sun,
snow, and ice.
Weatherstrips
Apply weatherstrip lubricant on
weatherstrips to make them last
longer, seal better, and not stick or
squeak. Lubricate weatherstrips
once a year. Hot, dry climates may
require more frequent application.
Black marks from rubber material on
painted surfaces can be removed by
rubbing with a clean cloth. See
Recommended Fluids and
Lubricants0452.
Tires
Use a stiff brush with tire cleaner to
clean the tires.
Caution
Using petroleum-based tire
dressing products on the vehicle
may damage the paint finish and/
or tires. When applying a tire
dressing, always wipe off any
overspray from all painted
surfaces on the vehicle.
Wheels and Wheel Trim
Use a soft, clean cloth with mild
soap and water to clean the wheels.
After rinsing thoroughly with clean
water, dry with a soft, clean towel.
A wax may then be applied.
Caution
Chrome wheels and chrome
wheel trim may be damaged if the
vehicle is not washed after driving
on roads that have been sprayed
with magnesium chloride or
calcium chloride. These are used
on roads for conditions such as
(Continued)
Caution (Continued)
dust and ice. Always wash the
chrome with soap and water after
exposure.
Caution
To avoid surface damage on
wheels and wheel trim, do not
use strong soaps, chemicals,
abrasive polishes, cleaners,
or brushes. Use only GM
approved cleaners. Do not drive
the vehicle through an automatic
car wash that uses silicon carbide
tire/wheel cleaning brushes.
Damage could occur and the
repairs would not be covered by
the vehicle warranty.
Brake System
Visually inspect brake lines and
hoses for proper hook-up, binding,
leaks, cracks, chafing, etc. Inspect
disc brake pads for wear and rotors

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
434 Vehicle Care
for surface condition. Inspect drum
brake linings/shoes for wear or
cracks. Inspect all other brake parts.
Steering, Suspension, and
Chassis Components
Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of wear at
least once a year.
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. Control arm ball joints on
1500 series vehicles are
maintenance-free.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 435
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.
Immediately remove any soils.
Newspapers or dark garments can
transfer color to the vehicle’s
interior.
Use a soft bristle brush to remove
dust from knobs and crevices on the
instrument cluster. Using a mild
soap solution, immediately remove
hand lotions, sunscreen, and insect
repellent from all interior surfaces or
permanent damage may result.
Use cleaners specifically designed
for the surfaces being cleaned to
prevent permanent damage. Apply
cleaners directly to the cleaning cloth. Do not spray cleaners on any
switches or controls. Remove
cleaners quickly.
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.
To prevent damage, do not clean
the interior using the following
cleaners or techniques:
.
Never use a razor or any other
sharp object to remove soil from
any interior surface.
. Never use a brush with stiff
bristles.
. Never rub any surface
aggressively or with too much
pressure.
. Do not use laundry detergents or
dishwashing soaps with
degreasers. For liquid cleaners,
use approximately 20 drops per
3.8 L (1 gal) of water.
A concentrated soap solution will create streaks and attract dirt.
Do not use solutions that contain
strong or caustic soap.
. Do not heavily saturate the
upholstery when cleaning.
. Do not use solvents or cleaners
containing solvents.
Interior Glass
To clean, use a terry cloth fabric
dampened with water. Wipe droplets
left behind with a clean dry cloth.
If necessary, use a commercial
glass cleaner after cleaning with
plain water.
Caution
To prevent scratching, never use
abrasive cleaners on automotive
glass. Abrasive cleaners or
aggressive cleaning may damage
the rear window defogger.
Cleaning the windshield with water
during the first three to six months
of ownership will reduce tendency
to fog.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
436 Vehicle Care
Speaker Covers
Vacuum around a speaker cover
gently, so that the speaker will not
be damaged. Clean spots with water
and mild soap.
Coated Moldings
Coated moldings should be cleaned.
.When lightly soiled, wipe with a
sponge or soft, lint-free cloth
dampened with water.
. When heavily soiled, use warm
soapy water.
Fabric/Carpet/Suede
Start by vacuuming the surface
using a soft brush attachment. If a
rotating vacuum brush attachment is
being used, only use it on the floor
carpet. Before cleaning, gently
remove as much of the soil as
possible:
.Gently blot liquids with a paper
towel. Continue blotting until no
more soil can be removed.
. For solid soils, remove as much
as possible prior to vacuuming. To clean:
1. Saturate a clean, lint-free colorfast cloth with water.
Microfiber cloth is
recommended to prevent lint
transfer to the fabric or carpet.
2. Remove excess moisture by gently wringing until water does
not drip from the cleaning cloth.
3. Start on the outside edge of the soil and gently rub toward the
center. Fold the cleaning cloth
to a clean area frequently to
prevent forcing the soil in to the
fabric.
4. Continue gently rubbing the soiled area until there is no
longer any color transfer from
the soil to the cleaning cloth.
5. If the soil is not completely removed, use a mild soap
solution followed only by plain
water. If the soil is not completely
removed, it may be necessary to
use a commercial upholstery
cleaner or spot lifter. Test a small
hidden area for colorfastness before
using a commercial upholstery
cleaner or spot lifter. If ring
formation occurs, clean the entire
fabric or carpet.
After cleaning use a paper towel to
blot excess moisture.
Cleaning High Gloss Surfaces
and Vehicle Information and
Radio Displays
Use a microfiber cloth on high gloss
surfaces or vehicle displays. First,
use a soft bristle brush to remove
dirt that can scratch the surface.
Then gently clean by rubbing with a
microfiber cloth. Never use window
cleaners or solvents. Periodically
hand wash the microfiber cloth
separately, using mild soap. Do not
use bleach or fabric softener. Rinse
thoroughly and air dry before
next use.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 437
Caution
Do not attach a device with a
suction cup to the display. This
may cause damage and would
not be covered by the vehicle
warranty.
Instrument Panel, Leather,
Vinyl, Other Plastic Surfaces,
Low Gloss Paint Surfaces and
Natural Open Pore Wood
Surfaces
Use a soft microfiber cloth
dampened with water to remove
dust and loose dirt. For a more
thorough cleaning, use a soft
microfiber cloth dampened with a
mild soap solution.
Caution
Soaking or saturating leather,
especially perforated leather, as
well as other interior surfaces,
may cause permanent damage.(Continued)
Caution (Continued)
Wipe excess moisture from these
surfaces after cleaning and allow
them to dry naturally. Never use
heat, steam, or spot removers. Do
not use cleaners that contain
silicone or wax-based products.
Cleaners containing these
solvents can permanently change
the appearance and feel of
leather or soft trim, and are not
recommended.
Do not use cleaners that increase
gloss, especially on the instrument
panel. Reflected glare can decrease
visibility through the windshield
under certain conditions.
Caution
Use of air fresheners may cause
permanent damage to plastics
and painted surfaces. If an air
freshener comes in contact with (Continued)
Caution (Continued)
any plastic or painted surface in
the vehicle, blot immediately and
clean with a soft cloth dampened
with a mild soap solution.
Damage caused by air fresheners
would not be covered by the
vehicle warranty.
Care of Seat Belts
Keep belts clean and dry.
{Warning
Do not bleach or dye seat belt
webbing. It may severely weaken
the webbing. In a crash, they
might not be able to provide
adequate protection. Clean and
rinse seat belt webbing only with
mild soap and lukewarm water.
Allow the webbing to dry.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
438 Vehicle Care
Floor Mats
{Warning
If a floor mat is the wrong size or
is not properly installed, it can
interfere with the pedals.
Interference with the pedals can
cause unintended acceleration
and/or increased stopping
distance which can cause a crash
and injury. Make sure the floor
mat does not interfere with the
pedals.
Use the following guidelines for
proper floor mat usage:
. The original equipment floor
mats were designed for your
vehicle. If the floor mats need
replacing, it is recommended
that GM certified floor mats be
purchased. Non-GM floor mats
may not fit properly and may
interfere with the pedals. Always
check that the floor mats do not
interfere with the pedals. .
Do not use a floor mat if the
vehicle is not equipped with a
floor mat retainer on the driver
side floor.
. Use the floor mat with the
correct side up. Do not turn
it over.
. Do not place anything on top of
the driver side floor mat.
. Use only a single floor mat on
the driver side.
. Do not place one floor mat on
top of another.
Removing and Replacing the
Floor Mats
Pull up on the rear of the driver side
floor mat to unlock each retainer
and remove.
Reinstall by lining up the floor mat
retainer openings over the carpet
retainers and snapping into position.
Make sure the floor mat is properly
secured in place.
Verify the floor mat does not
interfere with the pedals.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Service and Maintenance 439
Service and
Maintenance
General Information
General Information . . . . . . . . . . 439
Maintenance Schedule
Maintenance Schedule . . . . . . . 441
Special Application Services
Special ApplicationServices . . . . . . . . . . . . . . . . . . . . 448
Additional Maintenance
and Care
Additional Maintenanceand Care . . . . . . . . . . . . . . . . . . . . 449
Recommended Fluids,
Lubricants, and Parts
Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . 452
Maintenance Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . 454
Maintenance Records
Maintenance Records . . . . . . . . 456
General Information
This maintenance section applies to
vehicles with a gasoline engine. For
diesel engine vehicles, see
"Maintenance Schedule" in the
Duramax diesel supplement.
Your vehicle is an important
investment. This section describes
the required maintenance for the
vehicle. Follow this schedule to help
protect against major repair
expenses resulting from neglect or
inadequate maintenance. It may
also help to maintain the value of
the vehicle if it is sold. It is the
responsibility of the owner to have
all required maintenance performed.
Your dealer has trained technicians
who can perform required
maintenance using genuine
replacement parts. They have
up-to-date tools and equipment for
fast and accurate diagnostics. Many
dealers have extended evening and
Saturday hours, courtesy
transportation, and online
scheduling to assist with service
needs. Your dealer recognizes the
importance of providing
competitively priced maintenance
and repair services. With trained
technicians, the dealer is the place
for routine maintenance such as oil
changes and tire rotations and
additional maintenance items like
tires, brakes, batteries, and wiper
blades.
Caution
Damage caused by improper
maintenance can lead to costly
repairs and may not be covered
by the vehicle warranty.
Maintenance intervals, checks,
inspections, recommended fluids,
and lubricants are important to
keep the vehicle in good working
condition.
Do not have chemical flushes that
are not approved by GM
performed on the vehicle. The
use of flushes, solvents, cleaners,
or lubricants that are not
(Continued)