2003 CADILLAC CTS service

6-3
CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.

Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.

Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around it. This may cause wind noise
and affect windshield washer performance. Check with
your dealer before adding equipment to the outside of
your vehicle.
Fuel
Gasoline Octane
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 it is bad
enough, it can damage your engine.

6-5 Additives
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.
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.
You should not have to add anything to your fuel.
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 specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage plastic and rubber parts.
That damage wouldn't be covered under your
warranty.
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
find. Never use leaded gasoline or any other fuel not
recommended in the previous text on fuel. Costly repairs
caused by use of improper fuel wouldn't be covered by
your warranty.
To check on fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you'll be driving.

6-16
Navigation System
Press the multi
-function button, next to the OK prompt
in the upper right of the display, to acknowledge the
Change Engine Oil message. This will clear the message
from the display and reset it.
To reset the oil life indicator, use the following steps:
1. Turn the system on by pressing the PWR/VOL knob
once. The PWR/VOL knob is located to the lower
left of the DIC display.
2. Press the INFO button located to the left
of the display to access the Vehicle Info
(Information) menu.
3. Turn the TUNE/SEL knob located to the lower right
of the display until Engine Oil Life is highlighted.
Press the knob once to select it.
4. Once XXX% Engine Oil Life is displayed, press the
multi
-function button next to the Reset prompt in the
upper right corner of the display.
The percentage will return to 100, and the oil life
indicator will be reset.
5. Repeat the steps if the percentage does not
return to 100.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don't 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 throw away 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
filter 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.

6-18
3. Pull out the old engine air cleaner/filter.
4. Install a new engine air cleaner/filter, if needed. See
ªNormal Maintenance Replacement Partsº later in
this section for the correct part number for the filter.
5. If the filter is replaced, reset the indicator by
pressing upward on the indicator from the bottom.
6. Reinstall the cover by reversing Steps 1 and 2.
Refer to the Maintenance Schedule to determine when to
replace the air filter.
See ªScheduled Maintenance Servicesº in the Index.
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/filter in place when
you're driving.

6-19
Passenger Compartment Air Filter
The passenger compartment air filter traps most of the
pollen from the air entering your vehicle. Like your
vehicle's engine air cleaner/filter, it needs to be changed
periodically. For how often to change the passenger
compartment air filter, see ªScheduled Maintenance
Servicesº in the Index.
The passenger compartment air filter is located
underneath the hood below the windshield wiper arm on
the passenger's side of the vehicle. See ªEngine
Compartment Overviewº in the Index for more
information on location.
Use the procedure listed below to replace the passenger
compartment air filter:
1. Turn the ignition to ON with the engine off.2. Turn on the windshield wipers and turn them off
again when the wipers are in the out
-wipe position.
The wipers will be straight up and down on
the windshield.
This will allow you access to the leaf screen
under which is located the passenger compartment
air filter.
3. Open the hood to access the engine compartment.
See ªHood Releaseº listed earlier in this section for
more information.
4. Remove the four screws that hold the leaf screen in
place and lift off the screen by lifting and sliding
toward the center of the vehicle.
5. Pull out on the two tabs located on each end of the
filter cover.
6. Lift the filter cover off by pulling it straight upward.
7. Remove the old filter and insert a new one. Make
sure the arrow on the filter is pointing toward the
passenger compartment.
See ªNormal Maintenance Replacement Partsº
later in this section for the correct part number for
the filter.
8. Reverse Steps 1 through 6 to reinstall the cover.

6-20
Automatic Transmission Fluid
It is not necessary to check the transmission fluid level.
A transmission fluid leak is the only reason for fluid
loss. If a leak occurs, take your vehicle to the dealership
service department and have it repaired as soon as
possible. You may also have your fluid level checked
by your dealer or service center when you have your
oil changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these
conditions, the fluid and filter do not require changing.NOTICE:
We recommend you use only fluid labeled
DEXRON-III, because fluid with that label is
made especially for your automatic transmission.
Damage caused by fluid other than
DEXRON
-III is not covered by your new
vehicle warranty.

6-21
Manual Transmission Fluid
When to Check
A good time to have it checked is when the engine oil is
changed. However, the fluid in your manual
transmission doesn't require changing.
How to Check
Because this operation can be difficult, you may
choose to have this done at your Cadillac dealership
service department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot exhaust
system parts, starting a fire. Too little fluid could
cause the transmission to overheat. Be sure to get
an accurate reading if you check your
transmission fluid.
Check the fluid level only when your engine is off, the
vehicle is parked on a level place and the transmission is
cool enough for you to rest your fingers on the
transmission case.
Then, follow these steps:
1. Remove the filler plug.
2. Check that the lubricant level is up to the bottom of
the filler plug hole.
3. If the fluid level is good, install the plug and be sure
it is fully seated. If the fluid level is low, add more
fluid as described in the next steps.
How to Add Fluid
Here's how to add fluid. Refer to the Maintenance
Schedule to determine what kind of fluid to use. See
ªRecommended Fluids and Lubricantsº in the Index.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid level up to the bottom of the
filler plug hole.
3. Install the filler plug. Be sure the plug is fully seated.

6-23
Hydraulic Clutch
It is not necessary to regularly check clutch fluid unless
you suspect there is a leak in the system. Adding fluid
won't correct a leak.
A fluid loss in this system could indicate a problem.
Have the system inspected and repaired.
When to Check and What to Use
The hydraulic clutch reservoir is located in the engine
compartment on the driver's side, near the brake master
cylinder reservoir. See ªEngine Compartment Overviewº
in the Index for more information on location.Refer to the Maintenance Schedule to determine how
often you should check the fluid level in your clutch
master cylinder reservoir and for the proper fluid. See
ªOwner Checks and Servicesº and ªRecommended
Fluids and Lubricantsº in the Index.
How to Check and Add Fluid
Make sure the fluid
level is at the MIN line
shown. If it isn't,
remove the cap and
add the proper fluid
until the level reaches
the MIN line on the
side of the reservoir.