2009 CADILLAC STS engine

How to Inspect the Engine Air
Cleaner/Filter
To inspect the air cleaner/lter remove the lter from the
vehicle and lightly shake the lter to release loose dust
and dirt. If the lter remains caked with dirt, a new lter
is required.
To inspect or replace the lter in the 3.6L V6 or
4.6L V8 engines, do the following:
1. Remove the two screws located on the top of
the cover.
2. Disconnect the coolant recovery hose so that
it is not going across the top of the engine air
cleaner/lter.
3. Loosen the clamp and remove the duct from the
passenger’s side of the engine air cleaner/lter.4. The two sides of the airbox are hinged at the
bottom. Open the airbox by pushing the top of
the airbox cover toward the engine.
5. Remove the air lter by lifting it straight up through
the opening in the airbox.
6. Inspect or replace the engine air cleaner/lter.
SeeMaintenance Replacement Parts on page 6-15
for the correct part number for the lter.
7. Reinstall the cover by reversing Steps 1 through 4.
If your vehicle has the 4.4L V8 STS-V engine, there
is a special procedure for checking and changing the
air cleaner/lter. Because this procedure is difficult,
you should have this done at the dealership service
department. Contact your dealer for additional
information or the procedure can be found in the service
manual. To purchase a service manual, seeService
Publications Ordering Information on page 7-15.
5-24

{CAUTION:
Operating the engine with the air cleaner/lter
off can cause you or others to be burned. The air
cleaner not only cleans the air; it helps to stop
ames if the engine backres. If it is not there and
the engine backres, you could be burned. Do not
drive with it off, and be careful working on the
engine with the air cleaner/lter off.
Notice:If the air cleaner/lter is off, a backre can
cause a damaging engine re. And, dirt can easily get
into the engine, which will damage it. Always have
the air cleaner/lter in place when you are driving.
Automatic Transmission Fluid
How to Check Automatic Transmission
Fluid
It is not necessary to check the transmission uid level.
A transmission uid leak is the only reason for uid loss.
If a leak occurs, take the vehicle to the dealer/retailer
service department and have it repaired as soon as
possible.
There is a special procedure for checking and changing
the transmission uid. Because this procedure is
difficult, you should have this done at the dealer/retailer
service department. Contact your dealer/retailer for
additional information or the procedure can be found
in the service manual. To purchase a service manual,
seeService Publications Ordering Information on
page 7-15.
Notice:Use of the incorrect automatic transmission
uid may damage the vehicle, and the damages
may not be covered by the vehicle’s warranty.
Always use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-13.
Change the uid and lter at the intervals listed in
Additional Required Services on page 6-6, and be sure
to use the uid listed inRecommended Fluids and
Lubricants on page 6-13.
5-25

Cooling System
The cooling system allows the engine to maintain the
correct working temperature.
A. Electric Engine Cooling Fan(s) (Out of view)
B. Mechanical Engine Cooling Fan (If equipped)
(Out of view)
C. Coolant Surge Tank and Pressure Cap{CAUTION:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{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)
3.6L V6 Engine shown, 4.6L V8 and
4.4L V8 STS-V Engines similar
5-26

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.
Notice:Using coolant other than DEX-COOL
®can
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 the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant
in the vehicle.
Engine Coolant
The cooling system in the vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst.
The following explains the cooling system and how to
check and add coolant when it is low. If there is a problem
with engine overheating, seeEngine Overheating on
page 5-34.
5-27

What to Use
{CAUTION:
Adding only plain water to the cooling system can
be dangerous. Plain water, or some other liquid
such as alcohol, can boil before the proper coolant
mixture will. The vehicle’s coolant warning system
is set for the proper coolant mixture. With plain
water or the wrong mixture, the engine could get
too hot but you would not get the overheat
warning. The engine could catch re and you or
others could be burned. Use a 50/50 mixture of
clean, drinkable water and DEX-COOL
®coolant.Use a 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant. If using this mixture, nothing else
needs to be added. This mixture:
Gives freezing protection down to−34°F (−37°C),
outside temperature.
Gives boiling protection up to 265°F (129°C),
engine temperature.
Protects against rust and corrosion.
Will not damage aluminum parts.
Helps keep the proper engine temperature.
Notice:If an improper coolant mixture is used,
the engine could overheat and be badly damaged.
The repair cost would not be covered by the vehicle
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core, and
other parts.
Notice:If extra inhibitors and/or additives are used
in the vehicle’s cooling system, the vehicle could
be damaged. Use only the proper mixture of
the engine coolant listed in this manual for the
cooling system. SeeRecommended Fluids and
Lubricants on page 6-13for more information.
5-28

Checking Coolant
The vehicle must be on a level surface when checking
the coolant level.
The coolant surge tank and pressure cap are located
on the driver’s side of the vehicle, toward the rear of
the engine compartment. SeeEngine Compartment
Overview on page 5-12for more information on location.Check to see if coolant is visible in the coolant surge
tank. If the coolant inside the coolant surge tank is boiling,
do not do anything else until it cools down. If coolant
is visible but the coolant level is not at or above the
FULL COLD/FROID 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 is cool before
this is done.
When the engine is cold, the coolant level should be at
or above the FULL COLD/FROID line on the side of the
coolant surge tank. Follow the arrow from the top of the
tank down the side to the horizontal mark. If it is not,
there could be a leak in the cooling system.
If the coolant is low, add the coolant or take the vehicle
to a dealer/retailer for service.
5-29

Checking Intercooler System Coolant
(4.4L V8 STS-V Engine Only)
The vehicle must be on a level surface when checking
the coolant level.
SeeEngine Compartment Overview on page 5-12for
the location of the intercooler system pressure cap.
Turn off the engine. When the engine is cold, the coolant
level should be visible in the intercooler ll neck.
How to Add Coolant to the 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.
Notice:This vehicle has a specic coolant ll
procedure. Failure to follow this procedure could
cause the engine to overheat and be severely
damaged.
5-30

{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.
{CAUTION:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.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.
5-31