GMC Sierra Classic 2007 Owner's Manual page 503

If No Steam Is Coming From
Your Engine
The ENGINE COOLANT HOT message, along
with a low coolant condition, can indicate a
serious problem.
If you get an engine overheat warning, but see or
hear no steam, the problem may not be too
serious. Sometimes the engine can get a little too
hot when you:
•
Climb a long hill on a hot day.
•
Stop after high-speed driving.
•
Idle for long periods in traffic.
•
Tow a trailer. See Towing a Trailer on
page 423.
If you get the ENGINE COOLANT HOT message
with no sign of steam, try this for a minute or so:
1. If your air conditioner is on, turn it off.
2. Turn on your heater to full hot at the highest
fan speed and open the windows as
necessary.
3. If you are in a traffic jam, shift to
NEUTRAL (N); otherwise, shift to the highest
gear while driving — DRIVE (D) or THIRD (3).
If you no longer have the overheat warning, you
can drive. Just to be safe, drive slower for
about 10 minutes. If the warning does not come
back on, you can drive normally.
If the warning continues, pull over, stop, park, and
fast idle your vehicle right away.
If there is still no sign of steam and your vehicle is
equipped with an engine-driven cooling fan,
push down the accelerator until the engine speed
is about twice as fast as normal idle speed for
at least three minutes while you are parked.
If there is still no sign of steam and your vehicle
is equipped with an electric engine cooling fan, idle
the engine for three minutes while you
are parked.
If you still have the warning, turn off the engine
and get everyone out of the vehicle until it
cools down. Also, see "Overheated Engine
Protection Operating Mode" later in this section.
You may decide not to lift the hood but to get
service help right away.
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