GMC 2012 Terrain Owner's Manual page 304

10-22 Vehicle Care
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.
Notice: Engine damage from
running the engine without
coolant is not covered by the
warranty.
If Steam is Coming from the
Engine Compartment
WARNING
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Just turn it
off and get everyone away from
the vehicle until it cools down.
Wait until there is no sign of
steam or coolant before you
open the hood.
If you keep driving when the
engine is overheated, the liquids
in it can catch fire. You or others
could be badly burned. Stop the
engine if it overheats, and get out
of the vehicle until the engine
is cool.
If No Steam is Coming from
the Engine Compartment
If an engine overheat warning 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.
If the overheat warning 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.