2007 CADILLAC STS service

If the octane is less than 87, you may notice a
heavy knocking noise when you drive. If this occurs,
use a gasoline rated at 87 octane or higher as soon
as possible. Otherwise, you might damage your
engine. If you are using gasoline rated at 87 octane
or higher and you hear heavy knocking, your engine
needs service.
If your vehicle has the 4.4L V8 engine
(VIN Code D), use premium unleaded gasoline with
a posted octane rating of 91 or higher. For best
performance, use premium unleaded gasoline with
a posted octane rating of 93. In an emergency, you
can use regular unleaded gasoline with an octane
rating of 87 or higher. If 87 octane fuel is used, do
not perform any aggressive driving maneuvers such
as wide open throttle applications. You may also
hear audible spark knock during acceleration. Rell
your tank with premium fuel as soon as possible to
avoid damaging your engine. If you are using
gasoline rated at 91 octane or higher and you hear
heavy knocking, your engine needs service.Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. SeeAdditives
on page 367for additional information.
California Fuel
If your vehicle is certied to meet California
Emissions Standards, it is designed to operate on
fuels that meet California specications. See the
underhood emission control label. If this fuel is not
available in states adopting California emissions
standards, your vehicle will operate satisfactorily on
fuels meeting federal specications, but emission
control system performance may be affected.
366

The malfunction indicator lamp may turn on and
your vehicle may fail a smog-check test. See
Malfunction Indicator Lamp on page 252. If this
occurs, return to your authorized GM dealer for
diagnosis. If it is determined that the condition is
caused by the type of fuel used, repairs may not be
covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United
States are now required to contain additives
that will help prevent engine and fuel system
deposits from forming, allowing your emission
control system to work properly. In most cases,
you should not have to add anything to your fuel.
However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations.
To help keep fuel injectors and intake valves clean,
or if your vehicle experiences problems due to
dirty injectors or valves, look for gasoline that is
advertised as TOP TIER Detergent Gasoline. Also,
your dealer has additives that will help correct
and prevent most deposit-related problems.Gasolines containing oxygenates, such as ethers
and ethanol, and reformulated gasolines may
be available in your area. General Motors
recommends that you use these gasolines if they
comply with the specications described earlier.
However, E85 (85% ethanol) and other fuels
containing more than 10% ethanol must not be
used in vehicles that were not designed for
those fuels.
Notice:Your vehicle was not designed for
fuel that contains methanol. Do not use
fuel containing methanol. It can corrode metal
parts in the fuel system and also damage
plastic and rubber parts. That damage would
not be covered under your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing
additive called methylcyclopentadienyl manganese
tricarbonyl (MMT); ask the attendant where you
buy gasoline whether the fuel contains MMT.
General Motors recommends against the use of
such gasolines. Fuels containing MMT can reduce
the life of spark plugs and the performance of
the emission control system may be affected. The
malfunction indicator lamp may turn on. If this
occurs, return to your dealer for service.
367

When the system has calculated that oil life has
been diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL SOON
message in the DIC will come on. SeeDIC
Warnings and Messages on page 264. Change
your oil as soon as possible within the next
600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for
over a year. However, your engine oil and lter
must be changed at least once a year and at this
time the system must be reset. Your dealer has
GM-trained service people who will perform this
work using genuine GM parts and reset the system.
It is also important to check your oil regularly and
keep it at the proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km)
since your last oil change. Remember to reset the
oil life system whenever the oil is changed.How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to
change your engine oil and lter based on vehicle
use. Anytime your oil is changed, reset the
system so it can calculate when the next oil
change is required. If a situation occurs where you
change your oil prior to a CHANGE ENGINE
OIL SOON message in the DIC being turned on,
reset the system.
After the oil has been changed, the CHANGE
ENGINE OIL SOON message must be reset. To
reset the message use the following procedure:
1. Press the up or down arrow to scroll the DIC
to show OIL LIFE.
2. Once the XXX% ENGINE OIL LIFE menu item
is highlighted, press and hold the RESET
button until the percentage shows 100%.
If the percentage does not return to 100% or if
the CHANGE ENGINE OIL SOON message
comes back on when you start your
vehicle, the engine oil life system has not
reset. Repeat the procedure.
384

What to Do with Used Oil
Used engine oil contains certain elements that may
be unhealthy for your skin and could even cause
cancer. Do not let used oil stay on your skin for very
long. Clean your skin and nails with soap and
water, or a good hand cleaner. Wash or properly
dispose of clothing or rags containing used engine
oil. See the manufacturer’s warnings about the use
and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from
the lter before disposal. Never dispose of oil by
putting it in the trash, pouring it on the ground, into
sewers, or into streams or bodies of water. Instead,
recycle it by taking it to a place that collects used
oil. If you have a problem properly disposing of your
used oil, ask your dealer, a service station, or a
local recycling center for help.
Supercharger Oil
Because they are technically qualied and have
the proper tools, you should have your dealer
perform this maintenance.
When to Check
SeeAdditional Required Services on page 508for
when the oil level should be checked.
What Kind of Oil to Use
Use only the recommended supercharger oil. See
Recommended Fluids and Lubricants on
page 516.
385

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.
SeeNormal Maintenance Replacement Parts
on page 518for 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 543.
{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 your engine, which will
damage it. Always have the air cleaner/lter in
place when you are driving.
387

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 dealership 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 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 543.
Notice:Use of the incorrect automatic
transmission uid may damage your vehicle,
and the damages may not be covered by
your warranty. Always use the automatic
transmission uid listed inRecommended
Fluids and Lubricants on page 516.
Change the uid and lter at the intervals listed in
Additional Required Services on page 508, and
be sure to use the uid listed inRecommended
Fluids and Lubricants on page 516.
388

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

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, shift to PARK (P) or
NEUTRAL (N) and let the engine idle.
2. Set the climate controls to the highest heat
setting and fan speed and open the windows,
as necessary.
If the coolant warning light is not on or the coolant
temperature gage does not indicate the engine
is overheating, you can drive. Just to be safe, drive
slower for about 10 minutes. If the warnings do
not come back on, drive normally.
If the warnings continue and you have not stopped,
pull over, stop, and park the vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while parked. If the warnings are
still indicated, turn off the engine and get everyone
out of the vehicle until it cools down. Also, see
“Overheated Engine Protection Operating Mode”
later in this section.
You might decide not to lift the hood but to get
service help right away.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 380.
395