2021 CHEVROLET COLORADO overheating

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
84 Instruments and Controls
Engine Coolant Temperature
Gauge
Metric
EnglishThis gauge shows the engine coolant
temperature.
If the pointer moves toward the warning
area at the high end of the gauge, the
engine is too hot.
This reading indicates the same thing as the
warning light. It means that the engine
coolant has overheated. If the vehicle has
been operating under normal driving
conditions, pull off the road, stop the
vehicle, and turn off the engine as soon as
possible. See
Engine Overheating 0250.
Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder light on
the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt. Then the
light stays on solid until the belt is buckled. This cycle may continue several times if the
driver remains or becomes unbuckled while
the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Passenger Seat Belt Reminder Light
There is a passenger seat belt reminder light
near the passenger airbag status indicator.
See
Passenger Sensing System 039.
When the vehicle is started, this light
flashes and a chime may come on to remind
passengers to fasten their seat belt. Then
the light stays on solid until the belt is
buckled. This cycle continues several times if
the passenger remains or becomes
unbuckled while the vehicle is moving.
If the passenger seat belt is buckled, neither
the chime nor the light comes on.
The front passenger seat belt reminder light
and chime may turn on if an object is put
on the seat such as a briefcase, handbag,

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
Driving and Operating 177
Warning (Continued)
Flowing or rushing water creates strong
forces. Driving through flowing water
could cause the vehicle to be carried
away. If this happens, you and other
vehicle occupants could drown. Do not
ignore police warnings and be very
cautious about trying to drive through
flowing water.
Hydroplaning
Hydroplaning is dangerous. Water can build
up under the vehicle's tires so they actually
ride on the water. This can happen if the
road is wet enough and you are going fast
enough. When the vehicle is hydroplaning, it
has little or no contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to slow
down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet weather
driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping equipment in
good shape.
.Keep the windshield washer fluid reservoir
filled.
.Have good tires with proper tread depth.
SeeTires 0268.
.Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through mountains
is different than driving on flat or rolling
terrain. Tips include:
.Keep the vehicle serviced and in good
shape.
.Check all fluid levels and brakes, tires,
cooling system, and transmission.
.Shift to a lower gear when going down
steep or long hills.
{Warning
Using the brakes to slow the vehicle on a
long downhill slope can cause brake
overheating, can reduce brake
performance, and could result in a loss of
braking. Shift the transmission to a lower
gear to let the engine assist the brakes
on a steep downhill slope.
{Warning
Coasting downhill in N (Neutral) or with
the ignition off is dangerous. This can
cause overheating of the brakes and loss
of steering assist. Always have the engine
running and the vehicle in gear.
.Drive at speeds that keep the vehicle in
its own lane. Do not swing wide or cross
the center line.
.Be alert on top of hills; something could
be in your lane (e.g., stalled car, crash).
.Pay attention to special road signs (e.g.,
falling rocks area, winding roads, long
grades, passing or no-passing zones) and
take appropriate action.
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and the road
creates less traction or grip, so drive
carefully. Wet ice can occur at about 0 °C
(32 °F) when freezing rain begins to fall.
Avoid driving on wet ice or in freezing rain
until roads can be treated.

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
188 Driving and Operating
Heater Cord Near Engine Air Cleaner, 2.5L L4Engine Shown, 3.6L V6 Engine Similar
To Use the Engine Heater
1. Turn off the engine.
2. Open the hood and unwrap the electricalcord. The cord is secured near the
coolant surge tank or to the engine air
cleaner. Carefully remove the cord.
Check the heater cord for damage. If it is
damaged, do not use it. See your dealer
for a replacement. Inspect the cord for
damage yearly.
3. Plug the cord into a normal, grounded 110-volt AC outlet.
{Warning
Improper use of the heater cord or an
extension cord can damage the cord and
may result in overheating and fire.
.Plug the cord into a three-prong
electrical utility receptacle that is
protected by a ground fault detection
function. An ungrounded outlet could
cause an electric shock.
.Use a weatherproof, heavy-duty,
15 amp-rated extension cord if needed.
Failure to use the recommended
extension cord in good operating
condition, or using a damaged heater
or extension cord, could make it
overheat and cause a fire, property
damage, electric shock, and injury.
.Do not operate the vehicle with the
heater cord permanently attached to
the vehicle. Possible heater cord and
thermostat damage could occur.
(Continued)
Warning (Continued)
.While in use, do not let the heater
cord touch vehicle parts or sharp
edges. Never close the hood on the
heater cord.
.Before starting the vehicle, unplug the
cord, reattach the cover to the plug,
and securely fasten the cord. Keep the
cord away from any moving parts.
4. Before starting the engine, be sure to unplug and store the cord as it was
before to keep it away from moving
engine parts. If you do not, it could be
damaged.
The length of time the heater should remain
plugged in depends on several factors. Ask a
dealer in the area where you will be parking
the vehicle for the best advice on this.
Retained Accessory Power (RAP)
When the ignition is turned from on to off,
the following features (if equipped) will
continue to function for up to 10 minutes,
or until the driver door is opened. These
features will also work when the ignition is
in RUN or ACC/ACCESSORY:

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
Driving and Operating 195
Caution (Continued)
transmission. The repair will not be
covered by the vehicle warranty. If the
vehicle is stuck, do not spin the tires.
When stopping on a hill, use the brakes
to hold the vehicle in place.
Low Traction Mode
If equipped, Low Traction Mode assists in
vehicle acceleration when road conditions
are slippery, such as with ice or snow. While
the vehicle is at a stop, select L2 using
Range Selection Mode. This will limit torque
to the wheels and help to prevent the tires
from spinning.
Tow/Haul Mode
If equipped, Tow/Haul Mode adjusts the
transmission shift pattern to reduce shift
cycling. While towing heavy loads, this
mode provides increased performance and
vehicle control.
Turn the Tow/Haul Mode on and off by
pressing the button on the center stack.
When the Tow/Haul Mode is enabled, a
light on the instrument cluster will come on.
SeeTow/Haul Mode Light 089 and
Hill and Mountain Roads 0177.
Also see “Tow/Haul Mode” underTowing
Equipment 0228.
If the vehicle has a diesel engine, the Tow/
Haul button activates the exhaust brake
system simultaneously. See “Exhaust Brake”
in the Duramax diesel supplement.
Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive engages the
front axle for extra traction.
Caution
Do not drive on clean, dry pavement in
4
m, or 4nfor an extended period of
time. These conditions may cause:
.Overheating.
.Oil leakage.
.Damage to internal and external
components of the front axle.
.Premature wear on the vehicle’s
powertrain.
Driving on clean, dry pavement in 4
mor
4
nmay:
.Cause a vibration to be felt in the
steering system.
.Cause tires to wear faster.
.Cause additional driveline noise.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the shift
lever is in P (Park). You or someone else
could be seriously injured. Be sure the
transfer case is in a drive gear —2
m, 4m,
(Continued)

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
222 Driving and Operating
The vehicle can tow in D (Drive). Shift the
transmission to a lower gear if the
transmission shifts too often under heavy
loads and/or hilly conditions.
When towing at higher altitudes, engine
coolant will boil at a lower temperature
than at lower altitudes. If the engine is
turned off immediately after towing at high
altitude on steep uphill grades, the vehicle
could show signs similar to engine
overheating. To avoid this, let the engine
run, preferably on level ground, with the
transmission in P (Park) for a few minutes
before turning the engine off. If the
overheat warning comes on, seeEngine
Overheating 0250.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer on a
level surface when possible. When parking your vehicle and your trailer
on a hill:
1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into
the curb if facing downhill or into traffic
if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, gradually release the brake pedal to
allow the chocks to absorb the load of
the trailer.
4. Reapply the brake pedal. Then apply the parking brake and shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
.Shift into a gear.
.Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Launching and Retrieving a Boat
Backing the Trailer into the Water
{Warning
.Have all passengers get out of the
vehicle before backing onto the sloped
part of the ramp. Lower the driver and
passenger side windows before
backing onto the ramp. This will
provide a means of escape in the
unlikely event the vehicle slides into
the water.
.If the boat launch surface is slippery,
have the driver remain in the vehicle
with the brake pedal applied while the
boat is being launched. The boat
launch can be especially slippery at
low tide when part of the ramp was
previously submerged at high tide. Do
not back onto the ramp to launch the
boat if you are not sure the vehicle
can maintain traction.
.Do not move the vehicle if someone is
in the path of the trailer. Some parts
of the trailer might be underwater and
not visible to people who are assisting
in launching the boat.

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
Driving and Operating 223
Disconnect the wiring to the trailer before
backing the trailer into the water to prevent
damage to the electrical circuits on the
trailer. Reconnect the wiring to the trailer
after removing the trailer from the water.
If the trailer has electric brakes that can
function when the trailer is submerged, it
might help to leave the electrical trailer
connector attached to maintain trailer brake
functionality while on the boat ramp.
To back the trailer into the water:1. If equipped, place the vehicle in four-wheel-drive high.
2. Slowly back down the boat ramp until the boat is floating, but no further than
necessary.
3. Press and hold the brake pedal, but do not shift into P (Park) yet.
4. Have someone place chocks under the front wheels of the vehicle.
5. Gradually release the brake pedal to allow the chocks to absorb the load of
the trailer. 6. Reapply the brake pedal. Then apply the
parking brake and shift into P (Park).
7. Release the brake pedal.
Pulling the Trailer from the Water
To pull the trailer of the water: 1. Press and hold the brake pedals.
2. Start the engine and shift into gear.
3. Release the parking brake.
4. Let up on the brake pedal.
5. Drive slowly until the tires are clear of the chocks.
6. Stop and have someone pick up and store the chocks.
7. Slowly pull the trailer from the water.
8. Once the vehicle and trailer have been driven from the sloped part of the boat
ramp, the vehicle can be shifted from
four-wheel-drive high. Shift into the drive
mode that is appropriate for the road
conditions.Caution
If the vehicle tires begin to spin and the
vehicle begins to slide toward the water,
remove your foot from the accelerator
pedal and apply the brake pedal. Seek
help to have the vehicle towed up
the ramp.
Maintenance when Trailer Towing
The vehicle needs service more often when
used to tow trailers. See Maintenance
Schedule 0312. It is especially important to
check the automatic transmission fluid,
engine oil, axle lubricant, belts, cooling
system, and brake system before and during
each trip.
Check periodically to see that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling When Trailer Towing
The cooling system may temporarily
overheat during severe operating conditions.
See Engine Overheating 0250.

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
236 Vehicle Care
Vehicle Care
General Information
General Information . . . . . . . . . . . . . . . . . . . 237
California Proposition 65 Warning . . . . . 237
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . . . . . . 237
Accessories and Modifications . . . . . . . . . 237
Vehicle Checks
Doing Your Own Service Work . . . . . . . . 238
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Engine Compartment Overview . . . . . . . 240
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Engine Oil Life System . . . . . . . . . . . . . . . . 245
Automatic Transmission Fluid . . . . . . . . . 246
Engine Air Cleaner/Filter . . . . . . . . . . . . . . 246
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 247
Engine Overheating . . . . . . . . . . . . . . . . . . . 250
Engine Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 252
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Battery - North America . . . . . . . . . . . . . . . 254
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 254
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Starter Switch Check . . . . . . . . . . . . . . . . . . 256
Automatic Transmission Shift Lock Control Function Check . . . . . . . . . . . . . . 256 Ignition Transmission Lock Check . . . . . . 256
Park Brake and P (Park) Mechanism
Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
Wiper Blade Replacement . . . . . . . . . . . . . 257
Windshield Replacement . . . . . . . . . . . . . . . 257
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . . . . . . . 258
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . 258
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 259
Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps . . . . . . 259
Taillamps, Stoplamps, and Back-Up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Electrical System
Electrical System Overload . . . . . . . . . . . . . 261
Fuses and Circuit Breakers . . . . . . . . . . . . . 261
Engine Compartment Fuse Block . . . . . . 262
Instrument Panel Fuse Block . . . . . . . . . . 266
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . 268
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
All-Terrain Tires . . . . . . . . . . . . . . . . . . . . . . . 269
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . 269
Tire Designations . . . . . . . . . . . . . . . . . . . . . . 271
Tire Terminology and Definitions . . . . . . 272 Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 274
Tire Pressure Monitor System . . . . . . . . . 275
Tire Pressure Monitor Operation . . . . . . . 275
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . . . 278
Tire Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . 278
When It Is Time for New Tires . . . . . . . . 279
Buying New Tires . . . . . . . . . . . . . . . . . . . . . 280
Different Size Tires and Wheels . . . . . . . . 281
Uniform Tire Quality Grading . . . . . . . . . . 281
Wheel Alignment and Tire Balance . . . . 283
Wheel Replacement . . . . . . . . . . . . . . . . . . . 283
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 284
Tire Changing . . . . . . . . . . . . . . . . . . . . . . . . . 285
Compact Spare Tire . . . . . . . . . . . . . . . . . . . 294
Full-Size Spare Tire . . . . . . . . . . . . . . . . . . . . 295
Jump Starting
Jump Starting - North America . . . . . . . . 296
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . . . . . . 298
Recreational Vehicle Towing . . . . . . . . . . . 299
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

Chevrolet Colorado Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14430421) - 2021 - CRC - 2/10/20
248 Vehicle Care
3.6L V6 Engine
1. Coolant Surge Tank and Pressure Cap
2. 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 Lubricants0321
and
Maintenance Schedule 0312.
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, see Engine Overheating 0250.
What to Use
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
(Continued)
Warning (Continued)
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.
.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.