Cooling System - GMC 2006 DURAMAX Manual

If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N), and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn't come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there's 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're parked. If there is no sign of steam and your
vehicle is equipped with an electric cooling fan, idle the
engine for three minutes while you're parked. If you still
have the warning, turn off the engine and get everyone
out of the vehicle until it cools down.
You may decide not to lift the hood but to get service
help right away.

Cooling System

Pickup Models
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Surge Tank Pressure Cap
B. Coolant Surge Tank
C. Engine Fan
If the coolant inside the coolant surge tank is boiling,
don't do anything else until it cools down. The vehicle
should be parked on a level surface.
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