Page 233 of 357

Black plate (14,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7707484) - 2015 - crc - 10/1/14
10-14 Vehicle Care
Cooling System
2.4L L4 Engine
1. Engine Cooling Fan (Outof View)
2. Engine Coolant Surge Tank and Pressure Cap
3.6L V6 Engine
1. Engine Cooling Fans (Out
of View)
2. Engine Coolant Surge Tank and Pressure Cap
{Warning
An electric engine cooling fan
under the hood 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. 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
COLD FILL line. 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.
{Warning
Heater and radiator hoses, and
other engine parts, can be very
hot. Do not touch them. If you do,
you can be burned.
Do not run the engine if there is a
leak. If you run the engine, it
could lose all coolant. That could
cause an engine fire, and you
could be burned. Get any leak
fixed before you drive the vehicle.
Page 234 of 357

Black plate (15,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7707484) - 2015 - crc - 10/1/14
Vehicle Care 10-15
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.
{Caution
Using coolant other than
DEX-COOL®can cause
premature engine, heater core,
or radiator corrosion. In addition,
the engine coolant could require
changing sooner. Any repairs
would not be covered by the
vehicle warranty. Always use
DEX-COOL (silicate-free) coolant
in 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,
see
Engine Overheating on
page 10-18.
What to Use
{Warning
Adding only plain water or some
other liquid to the cooling system
can be dangerous. Plain water
and other liquids, can boil before
the proper coolant mixture will.
The coolant warning system is set
for the proper coolant mixture.
With plain water or the wrong
mixture, the engine could get too
hot but you would not get the
overheat warning. The engine
could catch fire and you or others
(Continued)
Warning (Continued)
could be burned. Use a 50/
50 mixture of clean, drinkable
water and DEX-COOL coolant.
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.
Page 236 of 357

Black plate (17,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7707484) - 2015 - crc - 10/1/14
Vehicle Care 10-17
{Warning
Steam and scalding liquids from a
hot cooling system can blow out
and burn you badly. They are
under pressure, and if you turn
the coolant surge tank pressure
cap—even a little —they can
come out at high speed. Never
turn the cap when the cooling
system, including the coolant
surge tank pressure cap, is hot.
Wait for the cooling system and
coolant surge tank pressure cap
to cool if you ever have to turn
the pressure cap.
{Warning
Adding only plain water or some
other liquid to the cooling system
can be dangerous. Plain water
and other liquids, can boil before
the proper coolant mixture will.
(Continued)
Warning (Continued)
The coolant warning system is set
for the proper coolant mixture.
With plain water or the wrong
mixture, the engine could get too
hot but you would not get the
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.
{Warning
You can be burned if you spill
coolant on hot engine parts.
Coolant contains ethylene glycol
and it will burn if the engine parts
are hot enough. Do not spill
coolant on a hot engine.
{Caution
In cold weather, water can freeze
and crack the engine, radiator,
heater core, and other parts. Use
the recommended coolant and
the proper coolant mixture.
1. Remove the coolant surge tankpressure 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
Page 237 of 357

Black plate (18,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7707484) - 2015 - crc - 10/1/14
10-18 Vehicle Care
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 withthe proper DEX-COOL coolant
mixture, to the COLD FILL line. 4. With the coolant surge tank
pressure cap off, start the
engine and let it run until the
upper radiator hose can be felt
getting hot. Watch out for the
engine cooling fan(s).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
DEX-COOL coolant mixture to
the coolant surge tank until the
level reaches the COLD
FILL line.
5. Replace the pressure cap. Be sure the pressure cap is
hand-tight.{Caution
If the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured. Check the level in the coolant surge
tank when the cooling system has
cooled down. If the coolant is not at
the proper level, repeat Steps 1–
3 and reinstall the pressure cap.
If the coolant still is not at the proper
level when the system cools down
again, see your dealer.
Engine Overheating
The vehicle has an indicator to warn
of engine overheating. There is an
engine coolant temperature warning
light on the vehicle's instrument
panel. See
Engine Coolant
Temperature Gauge on page 5-9.
The decision may be made not to lift
the hood when this warning
appears, but instead get service
help right away. See Roadside
Assistance Program on page 13-5.
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)