2021 GMC TERRAIN warning

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
266 Vehicle Care
How to Inspect/Replace the Engine Air
Cleaner/Filter
Do not start the engine or have the engine
running with the engine air cleaner/filter
housing open. Before removing the engine
air cleaner/filter, make sure that the engine
air cleaner/filter housing and nearby
components are free of dirt and debris. Do
not clean the engine air cleaner/filter or
components with water or compressed air.
1. Screws
2. Air Duct Clamp
3. Electrical Connector
To inspect or replace the engine air cleaner/
filter:1. Open the hood. See Hood0259.
2. Loosen the screw on the air duct clamp (2) and remove the air duct hose
from the cover.
3. Remove the four screws (1) and remove the air cleaner/filter cover, keeping the
wiring harness electrical connector (3)
connected to the sensor.
4. Pull straight up on the cover, and while holding the cover, remove the air
cleaner/filter.
{Warning
If part replacement is necessary, the part
must be replaced with one of the same
part number or with an equivalent part.
Use of a replacement part without the
same fit, form, and function may result
in personal injury or damage to the
vehicle.
5. Inspect or replace the air cleaner/filter.
How to Reinstall the Engine Air Cleaner/
Filter
1. Align the air cleaner/filter with the indicated point on the base of the air
cleaner/filter housing and install the air
cleaner/filter. The outer air cleaner/filter
seal must be fitted properly in the air
cleaner/filter housing.
2. Align the air cleaner/filter housing cover tabs to the air cleaner/filter housing.
3. Install the air cleaner/filter housing cover using the four screws.
4. Slide the air duct onto the cover assembly and tighten the screw on the
air duct clamp.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
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/
Mexico-14420055) - 2021 - CRC - 11/13/20
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
272 Vehicle Care
pads are needed. The sound can come and
go or can be heard all the time when the
vehicle is moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound means
that soon the brakes will not work well.
That could lead to a crash. When the
brake wear warning sound is heard, have
the vehicle serviced.
Caution
Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can
cause a brake squeal when the brakes are
first applied or lightly applied. This does not
mean something is wrong with the brakes.
Properly torqued wheel nuts are necessary
to help prevent brake pulsation. When tires
are rotated, inspect brake pads for wear and
evenly tighten wheel nuts in the proper
sequence to torque specifications. See
Capacities and Specifications 0343.
Brake pads should be replaced as
complete sets.
Brake Pedal Travel
See your dealer if the brake pedal does not
return to normal height, or if there is a
rapid increase in pedal travel. This could be
a sign that brake service may be required.
Replacing Brake System Parts
Always replace brake system parts with
new, approved replacement parts. If this is
not done, the brakes may not work
properly. The braking performance expected
can change in many other ways if the
wrong replacement brake parts are installed
or if parts are improperly installed.
Brake Fluid
The brake master cylinder reservoir is filled
with GM approved DOT 3 brake fluid as
indicated on the reservoir cap. See Engine
Compartment Overview 0261 for the
location of the reservoir. Checking Brake Fluid
With the vehicle in P (Park) on a level
surface, the brake fluid level should be
between the minimum and maximum marks
on the brake fluid reservoir.
There are only two reasons why the brake
fluid level in the reservoir may go down:
.Normal brake lining wear. When new
linings are installed, the fluid level goes
back up.
.A fluid leak in the brake hydraulic system.
Have the brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid reservoir cap
and the area around the cap before
removing it.
Do not top off the brake fluid. Adding fluid
does not correct a leak. If fluid is added
when the linings are worn, there will be too
much fluid when new brake linings are
installed. Add or remove fluid, as necessary,
only when work is done on the brake
hydraulic system.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Vehicle Care 273
{Warning
If too much brake fluid is added, it can
spill on the engine and burn, if the
engine is hot enough. You or others could
be burned, and the vehicle could be
damaged. Add brake fluid only when
work is done on the brake hydraulic
system.
When the brake fluid falls to a low level,
the brake warning light comes on. See Brake
System Warning Light 095.
Brake fluid absorbs water over time which
degrades the effectiveness of the brake fluid.
Replace brake fluid at the specified intervals
to prevent increased stopping distance. See
Maintenance Schedule 0331.
What to Add
Use only GM approved DOT 3 brake fluid
from a clean, sealed container. See
Recommended Fluids and Lubricants 0339.
{Warning
The wrong or contaminated brake fluid
could result in damage to the brake
system. This could result in the loss of
(Continued)
Warning (Continued)
braking leading to a possible injury.
Always use the proper GM approved
brake fluid.
Caution
If brake fluid is spilled on the vehicle's
painted surfaces, the paint finish can be
damaged. Immediately wash off any
painted surface.
Battery - North America
The original equipment battery is
maintenance free. Do not remove the cap
and do not add fluid.
Refer to the replacement number shown on
the original battery label when a new
battery is needed. SeeEngine Compartment
Overview 0261 for battery location.
For replacement of the battery, see your
dealer.
The vehicle has an Absorbed Glass Mat
(AGM) 12-volt battery. Installation of a
standard 12-volt battery will result in
reduced 12-volt battery life. When using a 12-volt battery charger on the
12-volt AGM battery, some chargers have an
AGM battery setting on the charger.
If available, use the AGM setting on the
charger, to limit charge voltage to 14.8 volts.
Follow the charger manufacturer's
instructions.
Stop/Start System
The vehicle has a Stop/Start system to shut
off the engine to help conserve fuel. See
Stop/Start System
0201.
{Warning
WARNING: Battery posts, terminals, and
related accessories contain lead and lead
compounds, chemicals known to the
State of California to cause cancer and
birth defects or other reproductive harm.
Batteries also contain other chemicals
known to the State of California to cause
cancer. WASH HANDS AFTER HANDLING.
For more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See California Proposition 65 Warning 0258
and the back cover.