2007 PONTIAC G5 engine overheat

Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is
designed to remain in your vehicle for ve years or
150,000 miles (240 000 km), whichever occurs rst,
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 290.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,
or radiator corrosion. In addition, the engine
coolant may require changing sooner, at
the rst maintenance service after each
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.
287

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. See
Recommended Fluids and Lubricants on
page 385for more information.
288

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 290
for 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.
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 278for 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 167for more information.
290

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 167.
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.
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) for automatic transmission or
NEUTRAL for manual transmission, 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.
291

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 Cap
2.2L L4 Engine shown, 2.4L L4 Engine similar
292

{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.
{CAUTION:
Heater and radiator hoses, and other
engine parts, can be very hot. Do not
touch them. If you do, you can be burned.
CAUTION: (Continued)
CAUTION: (Continued)
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, 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.
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 could 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.
293

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. SeeEngine Coolant on
page 287for more information.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.
294

{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 let any
pressure still left to be vented out the
discharge hose.
295