2007 CADILLAC STS V radiator

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 393.
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.
389

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 once or
twice 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 516for more information.
390

Checking Coolant
The coolant surge tank and pressure cap are
located on the driver’s side of the vehicle, toward
the rear of the engine compartment. See
Engine Compartment Overview on page 373for
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 FULL COLD/FROID line on the side of the
surge tank. Follow the arrow from the top of
the tank down the side to the horizontal mark.
391

Cooling System
When you decide it is safe to lift the hood, this is
what you will see:
A. Engine Cooling Fans
B. Coolant Surge Tank and Pressure CapSome vehicles may have an engine driven fan, as
well as the electric pusher fans which are
located behind the vehicle’s grille.
{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.
When the engine is cold, the coolant level
should be at or slightly above the FULL
COLD/FROID line on the side of the coolant surge
tank. 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 else
in the cooling system.
3.6L V6 Engine shown, 4.6L V8 and 4.4L V8 STS-V
Engines similar
396

{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 fans
are running. If the engine is overheating, both 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. SeeOverheated Engine Protection
Operating Mode on page 395for information on
driving to a safe place in an emergency.
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.
397

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.
If no coolant is visible in the surge tank, add
coolant as follows:
1. 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
one-quarter of a turn. If you hear a hiss,
wait for that to stop. A hiss means there is still
some pressure left.2. Then keep turning the pressure cap slowly,
and remove it.
399

3. Fill the coolant surge tank with the proper
DEX-COOL®coolant mixture, to slightly
above the FULL COLD/FROID line on the
side of the coolant surge tank.
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. The
upper radiator hose is the largest of the
hoses which comes out of the radiator, on the
passenger side of the vehicle. Watch out
for the engine cooling fans.By this time, the coolant level inside the
coolant surge tank may be lower. If the level
is lower, add more of the proper mixture
to the coolant surge tank until the level
reaches the FULL COLD/FROID line on the
side of the coolant surge tank.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Start the engine and allow it to warm up.
How to Add Coolant to the Intercooler
System Fill Neck (4.4L V8 STS-V
Engine Only)
If you have not found a problem yet, turn the
engine off and allow it to cool down, then check to
see if coolant is visible within the horizontal
tube section of the ll neck. If coolant is not visible,
add a 50/50 mixture of clean, drinkable water
and DEX-COOL
®coolant to the ll neck. Be sure
the Intercooler System, including the Intercooler
System pressure cap, is cool before doing so. See
Engine Coolant on page 389for more information.
400

{CAUTION:
Turning the Intercooler System 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 Intercooler System pressure cap,
even a little, when the engine and
intercooler are hot.
{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
CAUTION: (Continued)
CAUTION: (Continued)
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.
401