air conditioning CHEVROLET SILVERADO 2500HD 2021 User Guide

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Vehicle Care 339
Tire Designations
Tire Size
The examples show a typical light truck
tire size.
Light Truck (LT-Metric) Tire
(1) Light Truck (LT-Metric) Tire:The
United States version of a metric tire
sizing system. The letters LT as the first
two characters in the tire size mean a
light truck tire engineered to standards
set by the U.S. Tire and Rim
Association.
(2) Tire Width
:The 3-digit number
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio
:A 2-digit number that
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in item 3 of the light truck (LT-Metric) tire
illustration, it would mean that the
tire's sidewall is 75 percent as high as it
is wide.
(4) Construction Code
:A letter code is
used to indicate the type of ply
construction in the tire. The letter R
means radial ply construction; the
letter D means diagonal or bias ply
construction.
(5) Rim Diameter
:Diameter of the
wheel in inches.
(6) Load Range
:Load Range.
(7) Service Description
:The service
description indicates the load index and
speed rating of a tire. If two numbers
are given as in the example, 120/116,
then this represents the load index for
single versus dual wheel usage (single/
dual). The speed rating is the maximum
speed a tire is certified to carry a load.
Tire Terminology and Definitions
Air Pressure:The amount of air inside
the tire pressing outward on each
square inch of the tire. Air pressure is
expressed in kPa (kilopascal) or psi
(pounds per square inch).
Accessory Weight
:The combined
weight of optional accessories. Some
examples of optional accessories are
automatic transmission, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship of a
tire's height to its width.
Belt
:A rubber coated layer of cords
between the plies and the tread. Cords
may be made from steel or other
reinforcing materials.
Bead
:The tire bead contains steel
wires wrapped by steel cords that hold
the tire onto the rim.
Bias Ply Tire
:A pneumatic tire in which
the plies are laid at alternate angles
less than 90 degrees to the centerline
of the tread.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Service and Maintenance 385
Passenger Compartment Air Filter
The passenger compartment air filter
removes dust, pollen, and other airborne
irritants from outside air that is pulled into
the vehicle. The filter should be replaced as
part of routine scheduled maintenance.
Inspect the passenger compartment air filter
every 36 000 km/22,500 miles or two years,
whichever comes first. Replace if necessary.
More frequent replacement may be needed
if the vehicle is driven in areas with heavy
traffic, areas with poor air quality, or areas
with high dust levels. Replacement may also
be needed if there is a reduction in air flow,
excessive window fogging, or odors.
Power Take Off (PTO) and Extended
Idle Use
When the vehicle is used with the PTO
equipment or used in a way that requires
extended idle time, one hour of use shall be
deemed the same as 53 km (33 mi).
SeeDriver Information Center (DIC) (Base
Level) 0119 or
Driver Information Center (DIC) (Midlevel and
Uplevel) 0120 for hourmeter, if equipped.
Air Conditioning Desiccant (Replace 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.
Tire Rotation and Required Services
Every 12 000 km/7,500 mi
Rotate the tires, if recommended for the
vehicle, and perform the following services.
See Tire Rotation 0348.
.Check engine oil level and oil
life percentage. If needed, change engine
oil and filter, and reset oil life system.
See Engine Oil 0305 and
Engine Oil Life System 0307.
.If equipped with the engine air filter life
system, check the air filter
life percentage. If necessary, replace the
engine air filter and reset the engine air
filter life system. See Engine Air Filter Life
System 0308. If the vehicle is not
equipped with the engine air filter life
system, inspect the engine air cleaner
filter. See Engine Air Cleaner/Filter 0309.
.Check engine coolant level. See Cooling
System 0310.
.Check windshield washer fluid level. See
Washer Fluid 0315.
.Check tire inflation pressures, including
the spare. See Tire Pressure0341.
.Inspect tire wear. See Tire Inspection
0 348.
.Visually check for fluid leaks.
.Inspect brake system. See Exterior Care
0 373.
.Visually inspect steering, suspension, and
chassis components for damage, including
cracks or tears in the rubber boots, loose
or missing parts, or signs of wear at least
once a year. See Exterior Care0373.
If equipped with grease fittings, lubricate
the suspension and steering components
every oil change.
.Inspect power steering for proper
attachment, connections, binding, leaks,
cracks, chafing, etc.
.Visually inspect drive shafts for excessive
wear, lubricant leaks or damage including:
tube dents, cracks, constant velocity joint
or universal joint looseness, cracked or
missing boots, loose or missing boot
clamps, center bearing excessive
looseness, missing or loose fasteners.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Service and Maintenance 387
Additional Required ServicesMaintenance Schedule Additional
Required Services - Normal
12 000 km/7,500 mi
24 000 km/15,000 mi
36 000 km/22,500 mi
48 000 km/30,000 mi 60 000 km/37,500 mi
72 000 km/45,000 mi84 000 km/52,500 mi
96 000 km/60,000 mi
108 000 km/67,500 mi 120 000 km/75,000 mi 132 000 km/82,500 mi
144 000 km/90,000 mi 156 000 km/97,500 mi
168 000 km/105,000 mi 180 000 km/112,500 mi
192 000 km/120,000 mi 204 000 km/127,500 mi 216 000 km/135,000 mi
228 000 km/142,500 mi
240 000 km/150,000 mi
Rotate tires and perform Required Services. Check engine oil
level and oil life percentage. Change engine oil and filter,
if needed.
Check engine air filter life percentage and status. Change
engine air filter, if needed. (1)
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
Inspect evaporative control system. (3)@ @@
Replace spark plugs. Inspect spark plug wires and/or boots.@
Change transfer case fluid, if equipped with 4WD. (4)@@@
Drain and fill engine cooling system. (5)@
Visually inspect accessory drive belts. (6)@
Replace brake fluid. (7)
Replace windshield wiper blades. (8)
@ @ @ @ @ @ @ @ @ @
Replace hood gas struts and tailgate dampener. (9)@ @
Replace air conditioning desiccant. (10)

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
388 Service and Maintenance
Footnotes—Maintenance Schedule
Additional Required Services - Normal
(1) Or every four years, whichever comes
first. If driving in dusty conditions, inspect
the filter at each oil change or more often
as needed. See Engine Air Cleaner/Filter
0 309.
(2) Or every two years, whichever comes
first. More frequent replacement may be
needed if the vehicle is driven in areas with
heavy traffic, poor air quality, areas with
high dust levels or are sensitive to
environmental allergens. Filter replacement
may also be needed if you notice reduced
airflow, windows fogging up, or odors. Your
local GM Service location can help you
determine when it is the right time to
replace your filter.
(3) Visually check all fuel and vapor lines
and hoses for proper attachment,
connection, routing, and condition. (4)
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 drive axles and should be
replaced.
(5) Or every five years, whichever comes
first. See Cooling System 0310.
(6) Or every 10 years, whichever comes first.
Inspect for fraying, excessive cracking,
or damage; replace, if needed.
(7) Replace brake fluid every five years. See
Brake Fluid 0317.
(8) Or every 12 months, whichever comes
first. See Wiper Blade Replacement 0322.
(9) Or every 10 years, whichever comes first.
See Gas Strut(s) 0323.
(10) Replace air conditioning desiccant every
seven years.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Service and Maintenance 389
Maintenance Schedule Additional
Required Services - Severe12 000 km/7,500 mi
24 000 km/15,000 mi
36 000 km/22,500 mi
48 000 km/30,000 mi 60 000 km/37,500 mi
72 000 km/45,000 mi84 000 km/52,500 mi
96 000 km/60,000 mi
108 000 km/67,500 mi 120 000 km/75,000 mi 132 000 km/82,500 mi
144 000 km/90,000 mi 156 000 km/97,500 mi
168 000 km/105,000 mi 180 000 km/112,500 mi
192 000 km/120,000 mi 204 000 km/127,500 mi 216 000 km/135,000 mi
228 000 km/142,500 mi
240 000 km/150,000 mi
Rotate tires and perform Required Services. Check engine oil
level and oil life percentage. Change engine oil and filter,
if needed.
Check engine air filter life percentage and status. Change
engine air filter, if needed. (1)
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
Inspect evaporative control system. (3)@ @@
Replace spark plugs. Inspect spark plug wires and/or boots.@
Change automatic transmission fluid and filter.@@@
Change transfer case fluid, if equipped with 4WD. (4)@@@@@@
Drain and fill engine cooling system. (5)@
Visually inspect accessory drive belts. (6)@
Replace brake fluid. (7)
Replace windshield wiper blades. (8)
@ @ @ @ @ @ @ @ @ @
Replace hood gas struts and tailgate dampener. (9)@ @
Replace air conditioning desiccant. (10)

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
390 Service and Maintenance
Footnotes—Maintenance Schedule
Additional Required Services - Severe
(1) Or every four years, whichever comes
first. If driving in dusty conditions, inspect
the filter at each oil change or more often
as needed. See Engine Air Cleaner/Filter
0 309.
(2) Or every two years, whichever comes
first. More frequent replacement may be
needed if the vehicle is driven in areas with
heavy traffic, poor air quality, areas with
high dust levels or are sensitive to
environmental allergens. Filter replacement
may also be needed if you notice reduced
airflow, windows fogging up, or odors. Your
local GM Service location can help you
determine when it is the right time to
replace your filter.
(3) Visually check all fuel and vapor lines
and hoses for proper attachment,
connection, routing, and condition.
(4) 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 drive axles and should be
replaced. (5)
Or every five years, whichever comes
first. See Cooling System 0310.
(6) Or every 10 years, whichever comes first.
Inspect for fraying, excessive cracking,
or damage; replace, if needed.
(7) Replace brake fluid every five years. See
Brake Fluid 0317.
(8) Or every 12 months, whichever comes
first. See Wiper Blade Replacement 0322.
(9) Or every 10 years, whichever comes first.
See Gas Strut(s) 0323.
(10) Replace air conditioning desiccant every
seven years.
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 0373.
Additional Maintenance
and Care
Your vehicle is an important investment and
caring for it properly may help to avoid
future costly repairs. To maintain vehicle
performance, additional maintenance
services may be required.
It is recommended that your dealer perform
these services —their trained dealer
technicians know your vehicle best. Your
dealer can also perform a thorough
assessment with a multi-point inspection to
recommend when your vehicle may need
attention.
The following list is intended to explain the
services and conditions to look for that may
indicate services are required.
Battery
The 12-volt battery supplies power to start
the engine and operate any additional
electrical accessories.
.To avoid break-down or failure to start
the vehicle, maintain a battery with full
cranking power.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
398 Technical Data
Vehicle Data
Capacities and Specifications
The following approximate capacities are given in metric and English conversions. SeeRecommended Fluids and Lubricants0393.
If the vehicle has a diesel engine, see the Duramax diesel supplement.
Application Capacities
Metric English
Air Conditioning Refrigerant For the air conditioning system refrigerant type and charge amount, see the refrigerant label under the hood. See yourdealer for more information.
Engine Cooling System* 14.6 L 15.4 qt
Engine Oil with Filter 7.6 L 8.0 qt
Fuel Tank
I2500 Series and 3500 Series Standard Box (Except Double Cab Diesel) 136.3 L 36.0 gal
I2500 Series and 3500 Series Standard Box (Double Cab Diesel) 111.3 L 29.4 gal
I2500 Series and 3500 Series Long Box (Except Regular Cab Diesel) 136.3 L 36.0 gal
I2500 Series and 3500 Series Long Box (Regular Cab Diesel) 106.0 L 28.0 gal

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
420 Index
IndexA
Accessories and Modifications . . . . . . . . . . . 302
Accessory Power . . . . . . . . . . . . . . . . . . . . . . . . . 229
Add-On Electrical Equipment . . . . . . . . . . . . . 297
Adding a Snow Plow or SimilarEquipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Additional Information OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Additional Maintenance and Care . . . . . . . . 390
Adjustments Lumbar, Front Seats . . . . . . . . . . . . . . . . . . . . 45
Agreements Trademarks and License . . . . . . . . . . . . . . . 190
Air Cleaner/Filter, Engine . . . . . . . . . . . . . . . . 309
Air Conditioning . . . . . . . . . . . . . . . . . . . . .199, 201
Air Filter
Life System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Air Filter, Passenger Compartment . . . . . . . 204
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Airbag System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
How Does an Airbag Restrain? . . . . . . . . . . 61
Passenger Sensing System . . . . . . . . . . . . . . 62
What Makes an Airbag Inflate? . . . . . . . . . 61
What Will You See after an AirbagInflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
When Should an Airbag Inflate? . . . . . . . . 60
Where Are the Airbags? . . . . . . . . . . . . . . . . 59 Airbags
Adding Equipment to the Vehicle . . . . . . . 66
Passenger Status Indicator . . . . . . . . . . . . . 110
Readiness Light . . . . . . . . . . . . . . . . . . . . . . . . 110
Servicing Airbag-Equipped Vehicles . . . . . . 66
System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Alarm
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . 27
Alert Lane Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Side Blind Zone (SBZA) . . . . . . . . . . . . . . . . . 260
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
All-Terrain Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Antenna Fixed Mast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Multi-band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Antilock Brake System (ABS) . . . . . . . . . . . . . 240 Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Apple CarPlay and Android Auto . . . . . . . . . 180
Assistance Program, Roadside . . . . . . . . . . . . 404
Assistance Systems for Driving . . . . . . . . . . 257
Assistance Systems for Parking and Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
422 Index
Check (cont'd)Ignition Transmission Lock . . . . . . . . . . . . . 322
Child Restraints Infants and Young Children . . . . . . . . . . . . . 69
Lower Anchors and Tethers forChildren . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84, 87
Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Circuit Breakers . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Cleaning Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Climate Control Systems . . . . . . . . . . . . . . . . . 199 Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . 199
Dual Automatic . . . . . . . . . . . . . . . . . . . . . . . . 201
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Cluster, Instrument . . . . . . . . . . . . . . . . . . . . . . 102
Collision Damage Repair . . . . . . . . . . . . . . . . . 407
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Connected Services Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 Connections
Connected Services . . . . . . . . . . . . . . . . . . . . 418
Control Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Traction and Electronic Stability . . . . . . . 242
Control Light Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Control of a Vehicle . . . . . . . . . . . . . . . . . . . . . 208
Controls Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 146
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Coolant
Engine Temperature Gauge . . . . . . . . . . . . 108
Engine Temperature Warning Light . . . . . 116
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199, 201
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Courtesy Transportation Program . . . . . . . . 406
Coverage Explanations . . . . . . . . . . . . . . . . . . . 170
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Cupholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Customer Assistance . . . . . . . . . . . . . . . . . . . . . 403
Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Text Telephone (TTY) Users . . . . . . . . . . . . 403
Customer Information
Publications Ordering Information . . . . . 408
Customer Satisfaction Procedure . . . . . . . . . 401
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410D
Damage Repair, Collision . . . . . . . . . . . . . . . . . 407
Danger, Warning, and Caution . . . . . . . . . . . . . .2
Data Collection Infotainment System . . . . . . . . . . . . . . . . . . . 411
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Data Recorders, Event . . . . . . . . . . . . . . . . . . . . 411
Database Coverage Explanations . . . . . . . . . 170
Daytime Running Lamps (DRL) . . . . . . . . . . . 136
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . . . 208
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Diagnostics Connected Services . . . . . . . . . . . . . . . . . . . . 419
Differential, Limited-Slip . . . . . . . . . . . . . . . . . 245
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . . . 207
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 22
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Drive Belt Routing, Engine . . . . . . . . . . . . . . .400
Driver Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Driver Assistance Systems . . . . . . . . . . . . . . . 247
Driver Information Center (DIC) . . . . . . 119, 120
Driver Mode Control . . . . . . . . . . . . . . . . . . . . . 244