GMC Terrain 2018 Owner's Manual page 272

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.
Engine Coolant
The engine cooling system in the
vehicle are filled with DEX-COOL
engine coolant mixture. This coolant
needs to be checked and changed
at appropriate levels.
See Recommended Fluids and
Lubricants 0 353 and Maintenance
Schedule 0 344.
The following explains the cooling
systems and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating 0 274.
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
(Continued)
Vehicle Care
Warning (Continued)
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
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