2021 CHEVROLET SILVERADO 2500HD low oil pressure

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
310 Vehicle Care
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 0312.
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.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
378 Vehicle Care
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. 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.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Vehicle Care 379
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.
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.

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
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
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
418 Connected Services
PressQ, then ask the Advisor to download
directions to the vehicle’s navigation system,
if equipped. After the call ends, the
navigation screen will provide prompts to
begin driving directions. Routes that are
sent to the navigation screen can only be
canceled through the navigation system.
See www.onstar.com (U.S.) or www.onstar.ca
(Canada).
Connections
The following services help with staying
connected.
For coverage maps, see www.onstar.com
(U.S.) or www.onstar.ca (Canada).
Ensuring Security
.Change the default passwords for the
Wi-Fi hotspot and myChevrolet mobile
application. Make these passwords
different from each other and use a
combination of letters and numbers to
increase the security.
.Change the default name of the SSID
(Service Set Identifier). This is your
network’s name that is visible to other
wireless devices. Choose a unique name
and avoid family names or vehicle
descriptions. Wi-Fi Hotspot (If Equipped)
The vehicle may have a built-in Wi-Fi
hotspot that provides access to the Internet
and web content at 4G LTE speed. Up to
seven mobile devices can be connected.
A data plan is required. Use the in-vehicle
controls only when it is safe to do so.
1. To retrieve Wi-Fi hotspot information, press
=to open the OnStar app on the
infotainment display, then select Wi-Fi
Hotspot. On some vehicles, touch Wi-Fi
or Wi-Fi Settings on the screen.
2. The Wi-Fi settings will display the Wi-Fi hotspot name (SSID), password, and on
some vehicles, the connection type (no
Internet connection, 3G, 4G, 4G LTE), and
signal quality (poor, good, excellent). The
LTE icon shows connection to Wi-Fi. It is
possible that the icon may not illuminate
even though the vehicle has an active
connection.
3. To change the SSID or password, press
Qor call 1-888-4ONSTAR to connect
with an Advisor. On some vehicles, the
SSID and password can be changed in
the Wi-Fi Hotspot menu. After initial set-up, your vehicle’s Wi-Fi
hotspot will connect automatically to your
mobile devices. Manage data usage by
turning Wi-Fi on or off on your mobile
device, using the myChevrolet mobile app,
or by contacting an OnStar Advisor. On
some vehicles, Wi-Fi can also be managed
from the Wi-Fi Hotspot menu.
MyChevrolet Mobile App (If Available)
Download the myChevrolet mobile app to
compatible Apple and Android smartphones.
Chevrolet users can access the following
services from a smartphone:
.Remotely start/stop the vehicle,
if factory-equipped.
.Lock/unlock doors, if equipped with
automatic locks.
.Activate the horn and lamps.
.Check the vehicle’s fuel level, oil life,
or tire pressure, if factory-equipped with
the Tire Pressure Monitor System.
.Send destinations to the vehicle.
.Locate the vehicle on a map (U.S.
market only).
.Turn the vehicle's Wi-Fi hotspot on/off,
manage settings, and monitor data
consumption, if equipped.
.Locate a dealer and schedule service.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
424 Index
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Forward Collision Alert (FCA) System . . . . 257
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . 236, 320
Four-Wheel-Drive Light . . . . . . . . . . . . . . . . . . . . 114
Frequency StatementRadio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Front Seats
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Heated and Ventilated . . . . . . . . . . . . . . . . . . 49
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Economy, Driving for Better . . . . . . . . . . . 207
Filling a Portable Fuel Container . . . . . . . 267
Filling the Tank . . . . . . . . . . . . . . . . . . . 265, 266
Foreign Countries . . . . . . . . . . . . . . . . . . . . . . 264
Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Low Fuel Warning Light . . . . . . . . . . . . . . . . 118
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 264
Recommended . . . . . . . . . . . . . . . . . . . . . . . . . 263
Top Tier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Full-Size Spare Tire . . . . . . . . . . . . . . . . . . . . . . . 366
Fuses
Engine Compartment Fuse Block . . . . . . . 329
Fuses and Circuit Breakers . . . . . . . . . . . . . 329 Fuses (cont'd)
Instrument Panel Fuse Block . . . . . . 332, 334
G
Garage Door Opener . . . . . . . . . . . . . . . . . . . . . . 131
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Gauges Engine Coolant Temperature . . . . . . . . . . . 108
Engine Oil Pressure . . . . . . . . . . . . . . . . . . . . 107
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . 106
Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Warning Lights and Indicators . . . . . . . . . 102
General Information Service and Maintenance . . . . . . . . . . . . . . 383
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Glass Replacement . . . . . . . . . . . . . . . . . . . . . . . 323
Global Positioning System (GPS) . . . . . . . . . 168
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
Guidance Problems with the Route . . . . . . . . . . . . . . 169
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Hazard Warning Flashers . . . . . . . . . . . . . . . . . 137
HD Radio Technology . . . . . . . . . . . . . . . . . . . . . 151
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Head-up Display . . . . . . . . . . . . . . . . . . . . . . . . . . 123
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 324
Daytime Running Lamps (DRL) . . . . . . . . . 136
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Headlamps, Front Turn Signal,Sidemarker, and Parking Lamps . . . . . . 325
High-Beam On Light . . . . . . . . . . . . . . . . . . . . 118
High/Low Beam Changer . . . . . . . . . . . . . . 136
Lamps On Reminder . . . . . . . . . . . . . . . . . . . . 118
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . . 96
Heated and Ventilated Front Seats . . . . . . . 49
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199, 201
High-Beam On Light . . . . . . . . . . . . . . . . . . . . . . 118
Hill and Mountain Roads . . . . . . . . . . . . . . . . . 215
Hill Descent Control (HDC) . . . . . . . . . . . . . . . 244