2004 PONTIAC GTO radiator

Engine Coolant
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 5-28.A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will do the following:
•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 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.
5-25

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 the proper 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 the proper coolant, you do not
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
5-26

Checking Coolant
The coolant surge tank is located in the engine
compartment on the driver’s side of the vehicle. See
Engine Compartment Overview on page 5-12for 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 coolant level should be checked at least weekly, by
looking at the level on the coolant reservoir when the
engine is cold. The vehicle must be on a level surface.
When your engine is cold, the coolant level should
be at or slightly above the COLD FILL mark, at
the center weld joint. The level rises when the engine is
running and drops when the engine cools down. If
the level falls below the weld joint, the coolant should
be added to a little over the mark. Do not overfill,
as coolant requires space to expand when warmed up.
If the Low Coolant message on the trip computer
display comes on and stays on, it means you’re low on
engine coolant. You should check the level as soon
as possible. You may have to check the coolant level
when it is hot. SeeEngine Overheating on page 5-28.
5-27

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,
with the parking brake applied, shift to PARK (P)
or NEUTRAL (N) and let the engine idle while
you get out and check that the cooling fan is
working.
2. If the fan is working and the temperature gauge
needle has not returned to its normal position
within a few minutes, stop the engine and remove
the ignition key.
Look for leaks at the radiator hoses and
connections, heater hoses and connections,
radiator, and water pump. Be careful when checking
these areas as they will probably still be hot. If
you find a major leak or other problems that may
have caused the engine to overheat, do not run the
engine until these problems have been corrected.
If you do not find anything wrong, you should check
the engine coolant level. SeeEngine Coolant on
page 5-25. You should also check the air intake
area below the front bumper to ensure that it is clear
of leaves and road grime.3. Turn off your air conditioning and 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, you can 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.
5-30

The coolant level should be at or above the COLD FILL
mark. If it isn’t, you may have a leak at the pressure
cap or in the radiator hoses, heater hoses, radiator,
water pump, or somewhere else 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.
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 isn’t, your vehicle needs service.Notice:If you operate the engine without coolant
or fail to maintain the cooling system properly,
you could damage the engine. The repairs would not
be covered by your warranty. Always follow the
maintenance schedule in this manual for
maintaining your cooling system. SeeCooling
System on page 5-31for more information.
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.
5-32

How to Add Coolant to the Coolant
Surge Tank
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 COLD
FILL 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.
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 radiator
pressure cap — even a little — they can come
out at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have
to turn the pressure cap.
5-33

{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. Park the vehicle on a level surface.
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 (left) 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. Keep turning the pressure cap slowly, and
remove it.
5-34

3. Then fill the coolant surge tank with the proper
mixture to the COLD FILL mark.
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 mark, add more of the proper
mixture to the coolant surge tank until the level
reaches the mark.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
See your dealer, if necessary.
5-35