2009 CADILLAC STS engine

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.
5-32

How to Add Coolant to the
Intercooler System Fill Neck
(4.4L V8 STS-V Engine Only)
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. SeeEngine Coolant on page 5-27for
more information.
{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.1. Remove the Intercooler System pressure cap
when the Intercooler System, including the upper
intercooler hoses, are 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 allows any pressure still left to
be vented.
2. Then keep turning the pressure cap slowly, and
remove it.
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3. Add the proper DEX-COOL®coolant mixture to the
ll neck, until the coolant reaches the COLD FILL
line on the ll neck.
With the Intercooler System pressure cap off, start
the engine and let it run for a couple of minutes.
Then turn the engine off. By this time, the coolant
level inside the ll neck may be lower. If the level
drops to where coolant is no longer visible in the
horizontal tube section of the ll neck, with the engine
off add more of the DEX-COOL
®coolant mixture
to the ll neck until the level is again visible in the
horizontal tube section.
4. Then replace the 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.
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.
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
The vehicle has several indicators to warn of engine
overheating.
There are two engine hot messages that could be
displayed in the Driver Information Center (DIC).
SeeDIC Warnings and Messages on page 3-79
DIC Warnings and Messages for more information.
If the engine is overheating, then you will nd a coolant
temperature gage and a coolant warning light on the
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-65andEngine Coolant Temperature
Warning Light on page 3-64for more information.
5-34

You may decide not to lift the hood when this warning
appears, but instead get service help right away.
SeeRoadside Service on page 7-7.
If you do decide to lift the hood, make sure the vehicle
is parked on a level surface.
Then check to see if the engine cooling fans are
running. If the engine is overheating, both fans should
be running. If they are not, do not continue to run
the engine and have the vehicle serviced.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
Overheated Engine Protection Operating Mode on
page 5-36for information on driving to a safe place
in an emergency.
Notice:If the engine catches re while driving
with no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by the
vehicle warranty. SeeOverheated Engine Protection
Operating Mode on page 5-36for information on
driving to a safe place in an emergency.If Steam Is Coming From The Engine
Compartment
{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. 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 the vehicles engine is
overheated, the liquids in it can catch re. You or
others could be badly burned. Stop the engine if it
overheats, and get out of the vehicle until the
engine is cool.
SeeOverheated Engine Protection Operating Mode
on page 5-36for information on driving to a safe
place in an emergency.
5-35

If No Steam Is Coming From The
Engine Compartment
An overheat warning, can indicate a serious problem.
If an engine overheat warning is displayed but no steam
can be seen or heard, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer.
If the overheat warning is displayed with no sign of
steam:
1. Turn the air off.
2. Turn the heater on to the highest temperature and
to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.
If the engine coolant temperature gage is no longer
in the overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive the
vehicle slow for about 10 minutes. Keep a safe vehicle
distance from the car in front of you. If the warning does
not come back on, continue to drive normally.If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for
three minutes while parked. If the warning is still
displayed, turn off the engine until it cools down.
Also, see″Overheated Engine Protection Operating
Mode″later in this section.
Overheated Engine Protection
Operating Mode
This operating mode allows your vehicle to be driven
to a safe place in an emergency. Should an overheated
engine condition exist, an overheat protection mode
which alternates ring groups of cylinders helps prevent
engine damage. In this mode, you will notice a loss in
power and engine performance. An engine overheat
warning will indicate that an overheat condition exists.
Driving extended miles (km) and/or towing a trailer in
the overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss and change the oil. SeeEngine
Oil on page 5-18.
5-36

Power Steering Fluid
SeeEngine Compartment
Overview on page 5-12for
reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering uid
unless you suspect there is a leak in the system or
you hear an unusual noise. A uid loss in this system
could indicate a problem. Have the system inspected
and repaired.
How to Check Power Steering Fluid
To check the power steering uid, do the following:
1. Turn the ignition off and let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a
clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the uid level on
the dipstick.
The level should be within the HOT mark. If necessary,
add only enough uid to bring the level within the mark.
What to Use
To determine what kind of uid to use, see
Recommended Fluids and Lubricants on page 6-13.
Always use the proper uid.
Notice:Use of the incorrect uid may damage
the vehicle and the damages may not be covered by
the vehicle’s warranty. Always use the correct uid
listed inRecommended Fluids and Lubricants on
page 6-13.
5-37

Windshield Washer Fluid
What to Use
When you need windshield washer uid, be sure to read
the manufacturer’s instructions before use. If you will be
operating your vehicle in an area where the temperature
may fall below freezing, use a uid that has sufficient
protection against freezing.
Adding Washer Fluid
The CHECK WASHER FLUID message will appear
on the Driver Information Center (DIC) when the uid
level is low. SeeDIC Warnings and Messages on
page 3-79for more information.
Open the cap with the
washer symbol on it.
Add washer uid until the
tank is full. SeeEngine
Compartment Overview
on page 5-12for reservoir
location.Notice:
When using concentrated washer uid, follow
the manufacturer’s instructions for adding water.
Do not mix water with ready-to-use washer uid.
Water can cause the solution to freeze and
damage your washer uid tank and other parts of
the washer system. Also, water does not clean as
well as washer uid.
Fill the washer uid tank only three-quarters
full when it is very cold. This allows for uid
expansion if freezing occurs, which could
damage the tank if it is completely full.
Do not use engine coolant (antifreeze) in your
windshield washer. It can damage the vehicle’s
windshield washer system and paint.
5-38

Brakes
Brake Fluid
The brake master
cylinder reservoir is lled
with DOT-3 brake uid.
SeeEngine Compartment
Overview on page 5-12
for reservoir location and
access.
There are only two reasons why the brake uid level in
the reservoir might go down:
The brake uid level goes down because of normal
brake lining wear. When new linings are installed,
the uid level goes back up.
A uid leak in the brake hydraulic system can also
cause a low uid level. Have the brake hydraulic
system xed, since a leak means that sooner
or later the brakes will not work well.Do not top off the brake uid. Adding uid does not
correct a leak. If uid is added when the linings are worn,
there will be too much uid when new brake linings are
installed. Add or remove brake uid, as necessary, only
when work is done on the brake hydraulic system.
{CAUTION:
If too much brake uid is added, it can spill on the
engine and burn, if the engine is hot enough. You
or others could be burned, and the vehicle could
be damaged. Add brake uid only when work is
done on the brake hydraulic system.
If the ignition is on and the brake uid is low, the
CHECK BRAKE FLUID message displays in the
Driver Information Center (DIC). SeeDIC Warnings
and Messages on page 3-79.
5-39