Chevrolet EXPRESS - 2011 Manual page 296

See
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not,
do not continue to run the engine
and have the vehicle serviced.
See if the engine cooling fan speed
increases when idle speed is
doubled by pushing the accelerator
pedal down. If it does not, the
vehicle needs service.
Turn off the engine.
or
.
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 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. See Driving on
Grades under
(Continued)
.