CADILLAC STS 2005 1.G Owners Manual

Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle.
Gasoline Octane
If your vehicle has the 3.6L V6 engine, use regular
unleaded gasoline with a posted octane of 87 or higher.
However, for best performance and for trailer towing,
you may wish to use middle grade or premium unleaded
gasoline. If the octane is less than 87, you may get 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 your vehicle has the 4.6L V8 engine, use premium
unleaded gasoline with a posted octane of 91 or higher
for best performance. You may also use middle
grade or regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may be slightly
reduced. If the octane is less than 87, you may get 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.
Gasoline Specications
It is recommended that gasoline meet specications
which were developed by automobile manufacturers
around the world and contained in the World-Wide Fuel
Charter which is available from the Alliance of Automobile
Manufacturers at www.autoalliance.org/fuel_charter.htm.
Gasoline meeting these specications could provide
improved driveability and emission control system
performance compared to other gasoline.
5-5

California Fuel
If your vehicle is certied to meet California Emission
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. The malfunction indicator
lamp may turn on and your vehicle may fail a
smog-check test. SeeMalfunction Indicator Lamp on
page 3-68. 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.
General Motors recommends that you buy gasolines
that are advertised to help keep fuel injectors and intake
valves clean. If your vehicle experiences problems
due to dirty injectors or valves, try a different brand of
gasoline. Also, your GM dealer has additives that
will help correct and prevent most deposit-related
problems.
5-6

Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specications described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the 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 does not recommend 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 authorized GM
dealer for service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
be covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-7

Filling the Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Keep sparks, ames, and smoking materials
away from fuel. Do not leave the fuel pump
unattended when refueling your vehicle — this
is against the law in some places. Keep
children away from the fuel pump; never let
children pump fuel.The tethered fuel cap is
located behind a hinged
fuel door on the
passenger’s side of the
vehicle.
To open the fuel door, press on the rear edge of the
fuel door and it will pop open.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). The fuel cap has a spring in it; if the
cap is released too soon, it will spring back to the right.
5-8

While refueling, hang the tethered fuel cap from the
hook on the fuel door.
{CAUTION:
If you spill fuel and then something ignites it,
you could be badly burned. Fuel can spray out
on you if you open the fuel cap too quickly.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any hiss noise
to stop. Then unscrew the cap all the way.
Be careful not to spill fuel. Do not top off or overll the
tank, and wait a few seconds after you have nished
pumping before removing the nozzle. Clean fuel
from painted surfaces as soon as possible. See
Washing Your Vehicle on page 5-89.
When replacing the fuel cap, turn it to the right
(clockwise) until it clicks. Make sure the cap is fully
installed. The diagnostic system can determine if the fuel
cap has been left off or improperly installed. This
would allow fuel to evaporate into the atmosphere. See
Malfunction Indicator Lamp on page 3-68.The Check Gas Cap message will appear on the Driver
Information Center (DIC) display if the fuel cap is not
reinstalled properly. SeeDIC Warnings and Messages
on page 3-78for more information.{CAUTION:
If a re starts while you are refueling, do not
remove the nozzle. Shut off the ow of fuel by
shutting off the pump or by notifying the
station attendant. Leave the area immediately.
Notice:If you need a new fuel cap, be sure to get
the right type. Your dealer can get one for you.
If you get the wrong type, it may not t properly.
This may cause your malfunction indicator lamp to
light and may damage your fuel tank and emissions
system. SeeMalfunction Indicator Lamp on
page 3-68.
5-9

Filling a Portable Fuel Container
{CAUTION:
Never ll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the gasoline vapor.
You can be badly burned and your vehicle
damaged if this occurs. To help avoid injury to
you and others:
Dispense gasoline only into approved
containers.
Do not ll a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed, or
on any surface other than the ground.
Bring the ll nozzle in contact with the
inside of the ll opening before operating
the nozzle. Contact should be maintained
until the lling is complete.
Do not smoke while pumping gasoline.
Checking Things Under
the Hood
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing and tools away
from any underhood electric fan.
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
5-10

Hood Release
To open the hood, do the following:
1. Pull the hood release lever inside the vehicle. It is
located on the lower left side of the instrument panel.2. Then go to the front of the vehicle and nd the
secondary hood release lever. The lever is
located under the front edge of the grille near the
center. Move the release lever to the side and raise
the hood.
Before closing the hood, be sure all the ller caps are
on properly. Then pull the hood down and close it rmly.
5-11

Engine Compartment Overview
3.6L V6 engine
5-12

Your vehicle may be equipped with front compartment
underhood sight shields, which surround the vehicle’s
engine cover. These sight shields will need to be
removed in order to access some of the underhood
components in your vehicle.
To remove the sight shields, turn the fasteners on each
shield to the left until they pop out. Then remove the
fasteners and lift the shields up and away from the
shock towers that support them.
After you have removed the sight shields (if equipped)
on the 3.6L V6 engine, here is what you will see:
A. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-96.
B. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-32.
C. Battery. SeeBattery on page 5-37.D. Passenger Compartment Air Filter. SeePassenger
Compartment Air Filter on page 3-58.
E. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-31.
F. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-15.
G. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-15.
H. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-34.
I. Engine Coolant Surge Tank and Pressure Cap. See
Coolant Surge Tank Pressure Cap on page 5-24
andCooling System on page 5-27.
J. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-20.
5-13

4.6L V8 engine
5-14