cooling CHEVROLET COLORADO 2021 Duramax Diesel Supplement

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
22 Driving and Operating
Continue to follow the instructions in the
DIC messages. Hold the exhaust brake
switch on the center stack below the climate
controls for more than three seconds, and
then release it, to begin the regeneration
process.
If the EXHAUST BRAKE ON message displays,
then the switch was released too soon.
Press it again to turn off the exhaust brake,
then try again when the DIC message
prompts.
When manual regeneration begins, the
engine speed increases, the engine cooling
fan sound increases, and a DIC message
indicates that cleaning is in progress.
A DIC message will display when cleaning
has completed. The message will remain as
long as cleaning is not necessary. Cleaning
could take up to 30 minutes. Upon
completion, the engine will return to normal
idle, but exhaust components will remain
hot for several minutes. Do not move the
vehicle until the exhaust has had time to
cool. Manual regeneration can be canceled
at any time by pressing the brake pedal or
turning the engine off. Unusual noises may
be heard if regeneration is interrupted.Diesel Exhaust Fluid{
Warning
Avoid getting Diesel Exhaust Fluid (DEF)
on your skin or in your eyes as it could
cause irritation. For more safety,
handling, and storage information, see
the Diesel Exhaust Fluid container label.
Caution
Use only DEF that is GM approved,
or fluid containing the API certified or ISO
22241 label. The use of other fluids could
damage the system, requiring costly
repairs that will not be covered by the
vehicle warranty.
Caution
Do not mix fuel with DEF, and do not put
DEF in the fuel tank. This could lead to
costly repairs that might not be covered
by the vehicle warranty.
Diesel Exhaust Fluid (DEF) is used with diesel
engines to reduce the amount of regulated
emissions produced. Products such as AdBlue are types of DEF, and are approved for use
in the vehicle as long as they have an API
certification label or meet ISO 22241. The
fluid level in the DEF tank must be
maintained for the vehicle to run properly.
DEF is not a fuel additive. DEF should not be
mixed with or added to diesel fuel. DEF
freezes when exposed to temperatures
below
−11 °C (12 °F). For DEF tank capacity
see Capacities and Specifications 082.
It is normal to hear the DEF system purge
fluid back into the tank after the vehicle is
shut off.
Locating Diesel Exhaust Fluid
DEF can be purchased at your dealer.
Additionally, some diesel truck fueling
stations or retailers may have DEF for
purchase. For vehicles with an active OnStar
or connected services plan, OnStar can help
to locate a DEF retailer. See “Customer
Assistance Offices” in the owner’s manual
for phone numbers to assist in contacting a
GM dealer. See Recommended Fluids and
Lubricants 078.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
52 Vehicle Care
Vehicle Care
General Information
Accessories and Modifications . . . . . . . . . . 52
Vehicle Checks
Engine Compartment Overview . . . . . . . . . 53
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Engine Oil Life System . . . . . . . . . . . . . . . . . 58
Automatic Transmission Fluid . . . . . . . . . . 58
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . 58
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 60
Engine Overheating . . . . . . . . . . . . . . . . . . . . 62
Battery (4-Cylinder Pickup Only) . . . . . . . . 63
Electrical System
Engine Compartment Fuse Block . . . . . . . 64
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
General Information
Accessories and Modifications
Adding non-dealer accessories or making
modifications to the vehicle can affect
vehicle performance and safety, including
such things as airbags, braking, stability,
ride and handling, emissions systems,
aerodynamics, durability, and electronic
systems like antilock brakes, traction control,
and stability control. These accessories or
modifications could even cause malfunction
or damage not covered by the vehicle
warranty.
Damage to vehicle components resulting
from modifications or the installation or use
of non-GM certified parts, including control
module or software modifications, is not
covered under the terms of the vehicle
warranty and may affect remaining
warranty coverage for affected parts.
GM Accessories are designed to complement
and function with other systems on the
vehicle. See your dealer to accessorize the
vehicle using genuine GM Accessories
installed by a dealer technician.
See the warranty manual.
Aftermarket Engine Performance
Enhancement Products and Modifications
Some aftermarket engine performance
products and modifications promise a way
to increase the horsepower and torque
levels of the vehicle's powertrain. You should
be aware that these products could have
harmful effects on the performance and life
of the engine, exhaust emission system,
transmission, and drivetrain. The engine,
transmission, and drivetrain have been
designed and built to offer industry leading
durability and performance in the most
demanding applications. Engine power
enhancement products may enable the
engine to operate at horsepower and torque
levels that could damage, create failure,
or reduce the life of the engine, engine
emission system, transmission, and
drivetrain. Damage, failure, or reduced life of
the engine, transmission, emission system,
drivetrain, or other vehicle components
caused by aftermarket engine performance
enhancement products or modifications
might not be covered under the vehicle
warranty.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
60 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
The cooling system allows the engine to
maintain the correct working temperature.
2.8L 4-Cylinder Engine Pickup Models
See“Cooling System” in the owner’s
manual.
2.8L 4-Cylinder Engine Van Models
1. Coolant Surge Tank
2. Coolant Surge Tank Pressure Cap
3. Engine Cooling Fan (Out of View)
{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.
{Warning
Do not touch heater or radiator 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
mixture. See Recommended Fluids and
Lubricants 078 and
Maintenance Schedule 073 or
Maintenance Schedule 077. The following explains the cooling system
and how to add coolant when it is low.
If there is a problem with engine
overheating, see
Engine Overheating 062.
A 50/50 mixture of clean, drinkable water
and DEX-COOL coolant will:
.Give freezing protection down to −37 °C
(−34 °F).
.Give boiling protection up to 129 °C
(265 °F).
.Protect against rust and corrosion.
.Help keep the proper engine temperature.
.Let the warning lights and gauges work
as they should.
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.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Vehicle Care 61
Use a 50/50 mixture of clean, drinkable
water and DEX-COOL coolant which will not
damage aluminum parts. If using this
mixture, nothing else needs to be added.
If coolant has to be added more than four
times a year, have your dealer check the
vehicle cooling system.
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 (2.8L 4-Cylinder Engine
Pickup Models)
See “Engine Coolant” in the owner’s manual. Checking Coolant (2.8L 4-Cylinder Engine Van
Models)
The coolant surge tank is near the center of
the engine compartment. See
Engine
Compartment Overview 053 for location.
The vehicle must be on a level surface.
When the engine is cold, the coolant level
should be at the indicated mark.
Adding Coolant (2.8L 4-Cylinder Engine Pickup
Models)
See “Engine Coolant” in the owner’s manual. Adding Coolant (2.8L 4-Cylinder Engine Van
Models)
Caution
If coolant is changed or added, always
add enough to fill the system completely
or engine damage may occur.
If more coolant is needed, add the proper
DEX-COOL coolant mixture at the surge tank,
but be careful not to spill it.
{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
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, (Continued)

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
62 Vehicle Care
Warning (Continued)
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
If no coolant is visible in the surge tank, add
coolant as follows:
2.8L 4-Cylinder Van Pressure Cap
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. Slowly fill the coolant surge tank. Do not
let the coolant level go above the
indicated mark in the tank until after the
engine comes to operating temperature
in Step 4.
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, slowly add more of the
proper mixture to the coolant surge tank
until it reaches the indicated mark.
5. Re-install the pressure cap. Be sure the pressure cap is hand-tight
and fully seated.
6. Verify coolant level after the engine is shut off and the coolant is cold.
If necessary, repeat Steps 1–6.
If the coolant level is still low after having
followed these steps twice, have the coolant
system checked by a certified technician at
the dealer for a possible leak.
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
There is an engine coolant temperature
gauge on the instrument cluster. See the
owner’s manual.
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.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Vehicle Care 63
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.
If No Steam Is Coming from the Engine
Compartment
A Driver Information Center (DIC) message,
along with a low coolant condition, can
indicate a serious problem.
If there is an engine overheat warning and
the vehicle does not have a low coolant
condition, and no steam is heard or seen,
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“Driving on Grades”
under “Driving Characteristics and Towing
Tips” in the owner’s manual. If the DIC message comes on with no sign
of steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in N (Neutral) while stopped. If it is safe to
do so, pull off the road, shift to P (Park)
or N (Neutral), and let the engine idle.
2. Turn on the heater to full hot at the highest fan speed and open the window
as necessary.
If the vehicle no longer has the overheat
warning, the vehicle can be driven. Just to
be safe, drive slower for about 10 minutes.
If the warning does not come back on, 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
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.
Battery (4-Cylinder Pickup Only)
Pickups with a 4-cylinder diesel engine are
equipped with an AGM (Absorbing Glass
Mat) 12-volt battery. Installation of a
standard 12-volt battery will result in
reduced cold cranking performance. When
using a battery charger on the AGM battery,
use the AGM setting on the charger,
if available, to limit charge voltage to
14.8 volts. Follow the charger manufacturer's
instructions. See “Battery - North America”
in the owner’s manual.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Vehicle Care 67
FusesUsage
F46 Cooling fan clutch F47 Heater crankcase ventilation
F48 Fog lamps
F49 Selective catalytic reduction power module wake up
F50 Trailer parking lamps F51 Horn
F52 –
F53 –
F54 –
F55 –
F56 Washer pump F57 –
F58 –
F59 –
F60 Mirror defogger F61 –
F62 Selective catalytic reduction power module
F63 – Fuses
Usage
F64 Trailer reverse lamps F65 Left trailer stoplamp/ Turnlamp
F66 Right trailer stoplamp/ Turnlamp
F67 Electric power steering
F68 –
F69 Battery regulated voltage control
F70 –
F71 –
F72 –
F73 –
F74 Generator F75 –
Relays Usage
K1 Air conditioning clutch
K2 Starter
K3 Powertrain sensor
K4 Wiper speed Relays
Usage
K5 Wiper control
K6 Cargo lamp/Bed lighting K7 Powertrain
K8 Fuel pump
K9 Front differential lock actuators
K10 Rear differential lock actuators
K11 Center high-mounted stoplamp
K12 Fuel heater
K13 Selective catalytic reduction power
module heater control/
Diesel exhaust fluid
control
K14 Trailer parking lamps K15 Run/Crank
K16 Cooling fan clutch K17 Rear window defogger/ Mirror defogger

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
Vehicle Care 69
The vehicle may not be equipped with all of
the fuses, relays, and features shown.Fuses Usage
1 Antilock brake system motor
2 Antilock brake system module
3 Right trailer stoplamp/ Turnlamp
4 –
5 –
6 Fuel system control module/Ignition
7 Body control module 5
8 Body control module 7
9 Body control module 4
10 Instrument cluster 11 Trailer wiring
12 –
13 Display/Mirrors/Rear vision camera
14 Washer
16 Horn Fuses Usage
17 Transmission
18 Air conditioning
19 Engine control module battery
20 Left stop/turn cutaway lamp
21 Left stop/turn trailer lamp
22 Right stop/turn cutaway lamp
23 NOx sensors
24 Diesel fuel pump 25 Auxiliary power outlet
26 Body control module 3 27 Special equipment option
28 Airbag
29 Steering wheel sensor
30 Engine control module/ Glow plug module/
Ignition Fuses Usage
31 Transmission control module/Ignition
32 Transmission control module battery
33 Obstacle detection
34 NOx sensors 35 Fuel operated heater module
36 Fuel system control module battery
41 Transmission control module 2, battery
signal
42 Trailer wiring
43 EV fan clutch
44 Starter solenoid 45 Engine control module, powertrain signal 1
46 DC-AC inverter 47 Cooling fan –low
51 Left high-beam headlamp

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
70 Vehicle Care
FusesUsage
52 Right high-beam headlamp
53 Left low-beam headamp
54 Right low-beam headlamp
55 Wipers
56 Canister vent solenoid
58 Body control module 2
59 Body control module 1 61 Crankcase vent heater
62 O2 sensor 2/EV fan
63 –
64 Mass airflow sensor/ Canister vent/Humidity
sensor
65 Ignition coils/injectors - odd
66 Daytime running lamps 2
67 Daytime running lamps 1–uplevel
68 Auxiliary stoplamps Fuses
Usage
69 Trailer power extension 70 Upfitter stoplamps 71 Fuel heater/FlexFuel sensor
72 Body control module 6
73 Lighter/Data link connector
74 Front blower 75 Engine control module, powertrain signal 3
76 Soot sensor 77 O2 sensor 1/ECM powertrain signal 2
78 Engine control module/ Powertrain
79 Ignition coils/injectors - even
Relays Usage
15 Run/Crank
37 NOx sensors
38 Fuel pump Relays
Usage
39 Crank
40 Air conditioning 48 EV fan clutch
49 Powertrain 50 –
57 Cooling fan –low
60 Cooling fan control
Auxiliary Fuse Block
The vehicle may not be equipped with all of
the fuses, relays, and features shown.

Chevrolet/GMC 2.8L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-14465442) - 2021 - CRC - 2/3/20
74 Service and Maintenance
Extended Idle Use
When the vehicle is used in a way that
requires extended idle time, one hour of use
shall be deemed the same as 33 miles. See
Driver Information Center (DIC)010 for
hourmeter.
Required Services 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.
See Engine Oil 055 and
Engine Oil Life System 058.
.Check engine coolant level. See Cooling
System 060.
.Visually check for fluid leaks.
.Inspect engine air cleaner filter. See
Engine Air Cleaner/Filter 058.
.Visually inspect fuel system for damage
or leaks.
.Visually inspect exhaust system and
nearby heat shields for loose or damaged
parts.