2021 GMC TERRAIN engine overheat

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Driving and Operating 251
Make wider turns than normal when towing,
so trailer will not go over soft shoulders,
over curbs, or strike road signs, trees,
or other objects. Always signal turns well in
advance. Do not steer or brake suddenly.
Driving on Grades
Reduce speed and shift to a lower gear
before starting down a long or steep
downhill grade. If the transmission is not
shifted down, the brakes may overheat and
result in reduced braking efficiency.
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 0270.
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.
Maintenance When Trailer Towing
The vehicle needs service more often when
used to tow trailers. See Maintenance
Schedule 0331. 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 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 0270.
Trailer Towing
Caution
Towing a trailer improperly can damage
the vehicle and result in costly repairs
not covered by the vehicle warranty. To
(Continued)

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Vehicle Care 257
Vehicle Care
General Information
General Information . . . . . . . . . . . . . . . . . . . 258
California Proposition 65 Warning . . . . . 258
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . . . . . . 258
Accessories and Modifications . . . . . . . . . 258
Vehicle Checks
Doing Your Own Service Work . . . . . . . . 259
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Engine Compartment Overview . . . . . . . . 261
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
Engine Oil Life System . . . . . . . . . . . . . . . . 264
Automatic Transmission Fluid . . . . . . . . . 265
Engine Air Filter Life System . . . . . . . . . . 265
Engine Air Cleaner/Filter . . . . . . . . . . . . . . 265
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 267
Engine Overheating . . . . . . . . . . . . . . . . . . . 270
Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Battery - North America . . . . . . . . . . . . . . . 273
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . 274
Starter Switch Check . . . . . . . . . . . . . . . . . . 274
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
Wiper Blade Replacement . . . . . . . . . . . . . 275
Windshield Replacement . . . . . . . . . . . . . . 276 Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . . . . . . . 277
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . 277
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 277
High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Front Turn Signal Lamps . . . . . . . . . . . . . . . 278
Taillamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
License Plate Lamp . . . . . . . . . . . . . . . . . . . . 279
Electrical System
Electrical System Overload . . . . . . . . . . . . 280
Fuses and Circuit Breakers . . . . . . . . . . . . 280
Engine Compartment Fuse Block . . . . . . . 281
Instrument Panel Fuse Block . . . . . . . . . . 284
Rear Compartment Fuse Block . . . . . . . . . 285
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . 287
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Summer Tires . . . . . . . . . . . . . . . . . . . . . . . . . 288
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . 288
Tire Designations . . . . . . . . . . . . . . . . . . . . . 290
Tire Terminology and Definitions . . . . . . 291
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Tire Pressure Monitor System . . . . . . . . . 294 Tire Pressure Monitor Operation . . . . . . 295
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . . . 298
Tire Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . 298
When It Is Time for New Tires . . . . . . . . 299
Buying New Tires . . . . . . . . . . . . . . . . . . . . . 300
Different Size Tires and Wheels . . . . . . . 301
Uniform Tire Quality Grading . . . . . . . . . . 301
Wheel Alignment and Tire Balance . . . . 302
Wheel Replacement . . . . . . . . . . . . . . . . . . . 302
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 303
Tire Sealant and Compressor Kit . . . . . . 305
Storing the Tire Sealant and
Compressor Kit . . . . . . . . . . . . . . . . . . . . . . 310
Tire Changing . . . . . . . . . . . . . . . . . . . . . . . . . 310
Compact Spare Tire . . . . . . . . . . . . . . . . . . . . 315
Jump Starting
Jump Starting - North America . . . . . . . . 316
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . . . . . . 318
Recreational Vehicle Towing . . . . . . . . . . . 320
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Vehicle Care 267
5. Verify that the wiring harness connectoris fully connected to the sensor on the
air cleaner/filter housing.
6. If equipped, reset the engine air filter life system after replacing the engine air
filter, see Engine Air Filter Life System
0 265.
{Warning
Operating the engine with the air
cleaner/filter off can cause you or others
to be burned. Use caution when working
on the engine. Do not start the engine or
drive the vehicle with the air cleaner/
filter off, as flames may be present if the
engine backfires.
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
1. Engine Cooling Fan (Out of View)
2. Engine Coolant Surge Tank and
Pressure Cap
{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.
If the coolant inside the coolant surge tank
is boiling, do not do anything else until it
cools down. The vehicle should be parked on
a level surface.
The coolant level should be at the top rib on
the middle of the tank. If it is not, the
vehicle may have a leak at the radiator
hoses, heater hoses, radiator, water pump,
or somewhere else in the cooling system.
If there seems to be no leak, with the
engine on, check to see if the electric engine
cooling fan is running. If the engine is
overheating, the fan should be running. If it
is not, the vehicle needs service. Turn off
the engine.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
268 Vehicle Care
Engine Coolant
The engine cooling system in the vehicle is
filled with DEX-COOL engine coolant mixture.
This coolant needs to be checked and
changed at appropriate levels. See
Recommended Fluids and Lubricants0339
and
Maintenance Schedule 0331.
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 0270.
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. If using this
mixture, nothing else needs to be added.
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.
Never dispose of engine coolant by putting
it in the trash, pouring it on the ground,
or pouring 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
The vehicle must be on a level surface when
checking the coolant level.
Check to see if coolant is visible in the
coolant surge tank. If the coolant inside the
coolant surge tank is boiling, do not do
anything else until it cools down. If coolant
is visible but the coolant level mark is not
visible, add a 50/50 mixture of clean,
drinkable water and DEX-COOL coolant at
the coolant surge tank to the top rib on the
middle of the tank, but be sure the cooling
system is cool before this is done. See
Engine Overheating 0270.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Vehicle Care 269
The coolant surge tank is located in the
engine compartment on the driver side of
the vehicle. SeeEngine Compartment
Overview 0261.
How to Add Coolant to the Coolant
Surge Tank
{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.
{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.
{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.
Caution
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
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-quarter of a
turn. If you hear a hiss, wait for that to
stop. This will allow any pressure still
left to be vented out the discharge hose.
2. Keep turning the pressure cap slowly and remove it.
3. Fill the coolant surge tank with theproper mixture to the indicated
level mark.
4. With the coolant surge tank pressure cap off, start the engine and let it run until
you can feel the upper radiator hose
getting hot. Watch out for the engine
cooling fans.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
270 Vehicle Care
By this time, the coolant level inside the
coolant surge tank may be lower. If the
level is lower, add more of the proper
mixture to the coolant surge tank until
the level reaches the indicated
level mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1–6.
If the coolant still is not at the proper
level when the system cools down again,
see your dealer.
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
The vehicle has an engine coolant
temperature gauge on the instrument
cluster and overheat messages in the Driver
Information Center (DIC) to warn of engine
overheating. See Engine Coolant
Temperature Gauge 091. The decision may be made not to lift the
hood when the engine coolant temperature
gauge is in the overheat zone or an engine
overheat DIC message displays, but instead
to get service help right away. See
Roadside
Assistance Program 0349.
If the decision to lift the hood is made,
make sure the vehicle is parked on a level
surface. Then check to see if the engine
cooling fan(s) are running. If the engine is
overheating, the fan(s) should be running.
If they are not, do not continue to run the
engine, and have the vehicle serviced.
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 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.
If No Steam Is Coming from the Engine
Compartment
If the engine coolant temperature gauge is
in the overheat zone or an engine overheat
DIC message is displayed but no steam can
be seen or heard, 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

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Vehicle Care 271
If the engine coolant temperature gauge is
in the overheat zone and an overheat DIC
message is displayed with no sign of steam:1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan
speed. Open the windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral), and
let the engine idle.
If the engine coolant temperature gauge is
no longer in the overheat zone or an
overheat DIC message no longer displays,
the vehicle can be driven. Continue to drive
the vehicle slowly for about 10 minutes.
Keep a safe distance from the vehicle in
front. If the engine coolant temperature
gauge does not go back to the overheat
zone or an overheat DIC message does not
display, continue to drive normally and have
the cooling system checked for proper fill
and function.
If the engine coolant temperature gauge is
still in the overheat zone or an overheat DIC
message still displays, pull over, stop, and
park the vehicle right away. If overheat
messages appear repeatedly, see your
dealer. If there is no sign of steam, idle the engine
for three minutes while parked. If the
engine coolant temperature gauge is still in
the overheat zone or an overheat DIC
message displays, turn off the engine until
it cools down.
Washer Fluid
What to Use
When windshield washer fluid is needed, be
sure to read the manufacturer's instructions
before use. If operating the vehicle in an
area where the temperature may fall below
freezing, use a fluid that has sufficient
protection against freezing.
Adding Washer Fluid
Open the cap with the washer symbol on it.
Add washer fluid until the tank is full. See
Engine Compartment Overview
0261 for
reservoir location.
Caution
.Do not use washer fluid that contains
any type of water repellent coating.
This can cause the wiper blades to
chatter or skip.
.Do not use engine coolant (antifreeze)
in the windshield washer. It can
damage the windshield washer system
and paint.
.Do not mix water with ready-to-use
washer fluid. Water can cause the
solution to freeze and damage the
washer fluid tank and other parts of
the washer system.
.When using concentrated washer fluid,
follow the manufacturer instructions
for adding water.
.Fill the washer fluid tank only
three-quarters full when it is very cold.
This allows for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake pads have built-in wear indicators
that make a high-pitched warning sound
when the brake pads are worn and new

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/-
Mexico-14420055) - 2021 - CRC - 11/13/20
368 Index
Driving (cont'd)Better Fuel Economy . . . . . . . . . . . . . . . . . . . 187
Characteristics and Towing Tips . . . . . . . . 249
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Hill and Mountain Roads . . . . . . . . . . . . . . 194
If the Vehicle is Stuck . . . . . . . . . . . . . . . . . 195
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 190
Off-Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 189
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 196
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Driving the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . .2
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
E
Electric Parking Brake . . . . . . . . . . . . . . . . . . . . . 212
Electric Parking Brake Light . . . . . . . . . . . . . . . 95
Electrical Equipment, Add-On . . . . . . . . . . . . 256
Electrical SystemEngine Compartment Fuse Block . . . . . . . 281
Fuses and Circuit Breakers . . . . . . . . . . . . . 280
Instrument Panel Fuse Block . . . . . . . . . . . 284
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
Rear Compartment Fuse Block . . . . . . . . . 285 Emergency
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . 265
Check Light (Malfunction Indicator) . . . . . 93
Compartment Overview . . . . . . . . . . . . . . . . 261
Coolant Temperature Gauge . . . . . . . . . . . . 91
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 267
Drive Belt Routing . . . . . . . . . . . . . . . . . . . . . 345
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 264
Oil Pressure Light . . . . . . . . . . . . . . . . . . . . . . . 98
Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
Power Messages . . . . . . . . . . . . . . . . . . . . . . . 108
Running While Parked . . . . . . . . . . . . . . . . . 208
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Engine Air Filter Life System . . . . . . . . . . . . . 265
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Equipment, Towing . . . . . . . . . . . . . . . . . . . . . . 254
Event Data Recorders . . . . . . . . . . . . . . . . . . . . 356
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Extended Parking . . . . . . . . . . . . . . . . . . . . . . . . 207
Extender, Seat Belt . . . . . . . . . . . . . . . . . . . . . . . 46
Exterior Lamp Controls . . . . . . . . . . . . . . . . . . . . 116
Exterior Lighting Battery Saver . . . . . . . . . . . 122
F
Filter, Engine Air Cleaner . . . . . . . . . . . . . . . . . . . . . 265
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Flashers, Hazard Warning . . . . . . . . . . . . . . . . . 119
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Fluid Automatic Transmission . . . . . . . . . . . . . . . 265
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Folding Seatback . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Forward Collision Alert (FCA) System . . . . 237
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Front Fog Lamp
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Heated and Ventilated . . . . . . . . . . . . . . . . . . 35
Front Turn Signal Lamps . . . . . . . . . . . . . . . . . 278
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247