cooling CADILLAC STS 2007 1.G User Guide

After you have removed the sight shields (if equipped) on the 4.4L V8 STS-V engine, here is what
you will see:
A. Battery. SeeBattery on page 408.
B. Underhood Fuse Block. SeeUnderhood Fuse
Block on page 488.
C. Passenger Compartment Air Filter. See
Passenger Compartment Air Filter on page 239.
D. Windshield Washer Fluid Reservoir. See
“Adding Washer Fluid” underWindshield
Washer Fluid on page 404.
E. Intercooler System Pressure Cap. SeeEngine
Coolant on page 389.
F. Power Steering Fluid Reservoir. SeePower
Steering Fluid on page 403.
G. Engine Oil Fill Cap. See “When to Add Engine
Oil” underEngine Oil on page 380.
H. Engine Oil Dipstick (Out of View). See
“Checking Engine Oil” underEngine Oil on
page 380.I. Brake Master Cylinder Reservoir. See “Brake
Fluid” underBrakes on page 405.
J. Engine Coolant Surge Tank and Pressure Cap.
SeeCoolant Surge Tank Pressure Cap on
page 393andCooling System on page 396.
K. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 386.
If your vehicle is equipped with front compartment
underhood sight shields, before closing the
hood be sure to reinstall the sight shields. To
reinstall the shields, locate the tabs on the left and
right sides and insert them into the openings in
the tower to tower brace. Then insert the fasteners
into the top of the shield and push the fasteners
back into place.
379

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 Intercooler System Coolant
(4.4L V8 STS-V Engine Only)
SeeEngine Compartment Overview on page 373
for the location of the intercooler system
pressure cap.Notice:This vehicle has a specic coolant ll
procedure. Failure to follow this procedure
could cause your engine to overheat and
be severely damaged.
Park the vehicle on a level surface and turn off the
engine. When the engine is cold, the coolant
level should be visible in the intercooler ll neck.
Adding Coolant
If you need more coolant, add the proper
DEX-COOL®coolant mixture at the intercooler ll
neck, but only when the engine is cool. See
Cooling System on page 396for instructions on
how to add coolant to the intercooler ll neck.
392

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

How to Add Coolant to the Coolant
Surge Tank
If you have not found a problem yet, check to see
if coolant is visible in the surge tank. If coolant
is visible but the coolant level is not at the FULL
COLD/FROID line on the side of the coolant
surge tank, 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 389for more information.
{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
CAUTION: (Continued)
CAUTION: (Continued)
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.
{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.
398

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