2006 CHEVROLET COBALT engine

What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL®coolant which will not damage
aluminum parts. If you use this coolant mixture, you do
not 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 6-12for more information.
Checking Coolant
The coolant surge tank is located in the engine
compartment on the driver’s side of the vehicle.
5-25

SeeEngine Compartment Overview on page 5-12
for more information on 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
COLD FILL line.
Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixture at the coolant surge tank, but only
when the engine is cool. If the coolant surge tank is
empty, a special ll procedure is necessary. SeeEngine
Overheating on page 5-29for instructions on “How to
Add Coolant to the Coolant Surge Tank.”
{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 and fully seated.
5-26

Checking Intercooler System Coolant
(2.0L L4 Supercharged Engine Only)
The intercooler system ll neck is located in the front of
the engine compartment, near the center of the
vehicle. SeeEngine Compartment Overview on
page 5-12for more information on location.
{CAUTION:
Turning the ll neck pressure cap when the
engine and intercooler are hot can allow steam
and scalding liquids to blow out and burn
you badly. Never turn the ll neck pressure
cap — even a little — when the engine and
intercooler are hot.
Park your vehicle on a level surface and turn off the
engine. When the engine is cold, the coolant level
should be visible within the horizontal tube section of
the ll neck. When the engine is warm, the coolant level
could be as high as the FULL HOT line on the ll
neck, or a little higher.
5-27

Adding Coolant to the Intercooler System
Fill Neck
If coolant is not visible in the ll neck, add a 50/50
mixture of clean, drinkable water and DEX-COOL®
coolant at the ll neck, but be sure that the cooling
system, including the ll neck pressure cap, is cool
before you do so.
{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
intercooler system pressure cap — even a
little — they can come out at high speed. Never
turn the cap when the intercooler system,
including the intercooler system pressure cap,
is hot. Wait for the intercooler system and
intercooler system pressure cap to cool if
you ever have to turn the pressure cap.
{CAUTION:
Adding only plain water to your intercooler
system can be dangerous. Plain water, or some
other liquid such as alcohol, can boil before the
proper coolant mixture will. With plain water or
the wrong mixture, your engine could get too
hot. 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:In cold weather, water can freeze and crack
the engine, intercooler, and other parts. Use the
recommended coolant and the proper coolant
mixture.
{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.
5-28

1. You can remove the ll neck pressure cap when
the intercooler system, including the upper
intercooler hose, is no longer hot. Turn the pressure
cap slowly counterclockwise about one-quarter of
a turn. If you hear a hiss, wait for that to stop. This
will allow any remaining pressure to be vented.
2. Then keep turning the pressure cap slowly, and
remove it.
3. Add the proper DEX-COOL
®coolant mixture to the
ll neck, until there is coolant visible in the horizontal
tube section of the ll neck.
4. With the ll neck pressure cap off, start the engine
and let it run for at least 30 seconds. Watch out for
the engine cooling fan. Turn the engine off. By this
time, the coolant level inside the ll neck may be
lower. If the level drops so that coolant is no longer
visible in the horizontal tube section of the ll neck,
add more of the DEX-COOL
®coolant mixture to the
ll neck until the level is again visible in the horizontal
tube section.
5. Replace the intercooler system pressure cap.
Be sure the pressure cap is hand-tight and fully
seated.
If the coolant is not at the proper level when the
system cools down again, see your dealer.
Coolant Surge Tank Pressure Cap
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.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-12for more
information on location.
Engine Overheating
You will nd an engine coolant temperature warning
light on your vehicle’s instrument panel. SeeEngine
Coolant Temperature Warning Light on page 3-32for
more information.
5-29

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 engine coolant temperature warning can indicate a
serious problem. SeeEngine Coolant Temperature
Warning Light on page 3-32.
If you get an engine coolant temperature 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.
5-30

If you get the engine coolant temperature warning with
no sign of steam, try this for a minute or so:
1. If you have an air conditioner and it is on, turn it off.
2. 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.
3. Turn on your heater to full hot at the highest fan
speed and open the windows 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 does not come back on, you can drive
normally.
If the warning continues and you have not stopped, pull
over, stop, and park your vehicle right away.
If there is still no sign of steam, you can 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.
You may decide not to lift the hood but to get service
help right away.Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Electric Engine Cooling Fan
B. Coolant Surge Tank and Pressure Cap2.2L L4 Engine shown, 2.4L L4 Engine similar
5-31

A. Electric Engine Cooling Fans
B. Intercooler System Pressure Cap
C. Coolant Surge Tank and Pressure Cap
{CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
If the coolant inside the coolant surge tank is boiling, do
not do anything else until it cools down. The vehicle
should be parked on a level surface.
The coolant level should be at the COLD FILL line. If it
is not, you may have a leak at the pressure cap or
in the radiator hoses, heater hoses, radiator, water
pump, or somewhere in the cooling system. 2.0L L4 Supercharged Engine
5-32