CHEVROLET COBALT 2006 1.G Owners Manual

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

{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 your vehicle is equipped with the 2.2L or 2.4L L4
engine and there seems to be no leak, with the engine
on, check to see if the electric engine cooling fan is
running. If the engine is overheating, the fan should be
running. If it is not, your vehicle needs service.If your vehicle is equipped with the 2.0L L4 Supercharged
engine and there seems to be no leak, with the engine
on, check to see if the electric engine cooling fans are
running. If the engine is overheating, the fans should be
running. If they are not, your vehicle needs service.
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 or radiator
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.
5-33

How to Add Coolant to the Coolant
Surge Tank
Notice:This vehicle 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, check to see if
coolant is visible in the coolant surge tank. If coolant is
visible but the coolant level is not at the COLD FILL
line, add a 50/50 mixture of clean, drinkable water and
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 5-24for more information.
2.2L and 2.4L L4 Engines
If no coolant is visible in the coolant 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. 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.
5-34

{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:In cold weather, water can freeze and crack
the engine, radiator, heater core 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.
1. You can remove the coolant surge tank pressure
cap when the cooling system, including the coolant
surge tank pressure cap and upper radiator
hose, is no longer hot. Turn the pressure cap slowly
counterclockwise about two or two and one-half
turns. If you hear a hiss, wait for that to stop. This
will allow any pressure still left to be vented out
the discharge hose.
2. Then keep turning the
pressure cap slowly,
and remove it.
5-35

3. Fill the coolant surge tank with the proper mixture,
to the COLD FILL line on the tank. Wait about
ve minutes, then check to see if the level is below
the COLD FILL line. If the level is below the line,
add additional coolant to bring the level up to
the line. Repeat this procedure until the level
remains constant at the COLD FILL line for at least
ve minutes.4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the
engine cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower than
the COLD FILL line, add more of the proper mixture
to the coolant surge tank until the level reaches
the COLD FILL line.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
See your dealer, if necessary.
2.0L L4 Supercharged Engine
If no coolant is visible in the coolant surge tank, you will
need to either see your dealer or refer to the Dealer
Service Manual for a special coolant service ll procedure
to ensure enough coolant is added. To purchase a
service manual, seeService Publications Ordering
Information on page 7-14.
5-36