2006 CHEVROLET DURAMAX engine overheat

What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOL®coolant which won’t damage
aluminum parts. If you use this coolant mixture,
you don’t need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle’s coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you would not get the overheat warning.
Your engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:If you use an improper coolant mixture, your
engine could overheat and be badly damaged. The
repair cost would not be covered by your warranty.
Too much water in the mixture can freeze and crack
the engine, radiator, heater core, and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice:If you use extra inhibitors and/or additives
in your vehicle’s cooling system, you could damage
your vehicle. Use only the proper mixture of the
engine coolant listed in this manual for the cooling
system. SeeRecommended Fluids and Lubricants
on page 6-15for more information.
5-35
ProCarManuals.com

Checking Coolant
The coolant surge tank
is located in the engine
compartment on the
passenger’s side of the
vehicle. SeeEngine
Compartment Overview
on page 5-18for more
information on its location.
{CAUTION:
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap — even a little — when the engine and
radiator are hot.The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the
FULL COLD mark.
Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixtureat the surge tank, but only when the
engine is cool. If the surge tank is empty, seeEngine
Overheating on page 5-39.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand- tight.
5-36
ProCarManuals.com

Van Models
The cooling system in your vehicle is filled with
DEX-COOL®engine coolant. This coolant is designed to
remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem with
engine overheating, seeEngine Overheating on
page 5-39.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
•Give freezing protection down to−34°F (−37°C)
•Give boiling protection up to 265°F (129°C)
•Protect against rust and corrosion
•Help keep the proper engine temperature
•Let the warning lights and gages work as they should
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core, radiator and
fuel operated heater (FOH) corrosion. In addition,
the engine coolant may require changing sooner, at
30,000 miles (50 000 km) or 24 months, whichever
occurs rst. Any repairs would not be covered by
your warranty. Always use DEX-COOL
®(silicate-free)
coolant in your vehicle.
What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOL®coolant which won’t damage
aluminum parts. If you use this coolant mixture,
you don’t need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle’s coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you would not get the overheat warning.
Your engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
Notice:If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost would not be covered by your
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core, and
other parts.
5-37
ProCarManuals.com

Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixtureat the coolant recovery tank, but be
careful not to spill it.
{CAUTION:
You can be burned if you spill coolant on hot
components in the engine compartment.
Coolant contains ethylene glycol, and it will
burn if the engine parts are hot enough. Do not
spill coolant on a hot engine or components in
the engine compartment.
When replacing the pressure cap, make sure it is
hand-tight.
Radiator Pressure Cap
The radiator pressure cap must be tightly installed.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Coolant Surge Tank Pressure Cap
The surge tank pressure
cap must be tightly
installed.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
You will find an engine coolant temperature gage on the
instrument panel cluster. For pickup models, the ENGINE
OVERHEATED message may appear in the Driver
Information Center (DIC). See your owner’s manual for
more information.
5-39
ProCarManuals.com

If Steam Is Coming From Your Engine
{CAUTION:
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 your engine is
overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catches re because you keep
driving with no coolant, your vehicle can be badly
damaged. The costly repairs would not be covered
by your warranty.
If No Steam Is Coming From
Your Engine
An overheat warning, along with a low coolant condition,
can indicate a serious problem.
If you get an engine overheat warning and don’t have a
low coolant condition, 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 “Driving on Grades” in the
owner’s manual Index.
5-40
ProCarManuals.com

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 vehicleuntil 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.
5-41
ProCarManuals.com

How to Add Coolant to the Coolant
Surge Tank
Notice:The diesel engine has a specic coolant
ll procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
If you haven’t found a problem yet, check to see
if coolant is visible in the surge tank. If coolant is visible
but the coolant level isn’t at or above the FULL COLD
mark, add a 50/50 mixture ofclean, drinkable waterand
DEX-COOL
®coolant at the coolant surge tank, but
be sure the cooling system, including the coolant surge
tank pressure cap, is cool before you do it. See
Engine Coolant on page 5-34for more information.
If no coolant is visible in the surge tank, add coolant
as follows:
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly.
They are under pressure, and if you turn the
coolant surge tank pressure cap — even a
little — they can come out at high speed.
CAUTION: (Continued)
CAUTION: (Continued)
Never turn the cap when the cooling system,
including the coolant surge tank pressure cap,
is hot. Wait for the cooling system and coolant
surge tank pressure cap to cool if you ever
have to turn the pressure cap.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle’s coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you would not get the overheat warning.
Your engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
5-43
ProCarManuals.com

{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them. If
you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an engine re, and you could be
burned. Get any leak xed before you drive the
vehicle.
If there seems to be no leak, start the engine again. See if
the engine cooling fan speed increases when idle speed
is doubled by pushing the accelerator pedal down. If it
does not, your vehicle needs service. Turn off the engine.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty.Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core, radiator and
fuel operated heater (FOH) corrosion. In addition,
the engine coolant may require changing sooner, at
30,000 miles (50 000 km) or 24 months, whichever
occurs rst. Any repairs would not be covered by
your warranty. Always use DEX-COOL
®(silicate-free)
coolant in your vehicle.
How to Add Coolant to the Coolant
Surge Tank
Notice:The diesel engine has a specic coolant ll
procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
If you have not found a problem yet, but the coolant level
is not at the COLD FILL mark, add a 50/50 mixture of
clean, drinkable water and DEX-COOL
®engine coolant
at the coolant surge tank. SeeEngine Coolant on
page 5-34for more information.
5-47
ProCarManuals.com