2003 CADILLAC CTS maintenance

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.

6-17
Engine Air Cleaner/Filter
The engine air cleaner/filter is in the engine
compartment on the driver's side of the vehicle, near the
front. See ªEngine Compartment Overviewº in the
Index for more information on location.The engine air cleaner/filter needs replacement
periodically. Use the information listed in this manual
as a guide for filter replacement intervals.
See ªMaintenance Scheduleº in the Index for more
information. In general, you should change the filter
whenever the indicator located on the cover turns
black. See the previous photo for the exact location
of the indicator.
The indicator may turn black earlier or later than the
suggested replacement intervals listed under
ªMaintenance Scheduleº in this manual. However, you
should replace the filter and reset the indicator once the
indicator turns black.
To check or replace the filter, do the following:
1. Remove the two screws located on the sides
of the cover.
2. Lift the cover off.

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.

6-21
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.

6-24
Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªPeriodic Maintenance
Inspectionsº and ªScheduled Maintenance Servicesº in
the Index.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.

6-33 Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built
-in wear indicators that
make a high
-pitched warning sound when the brake
pads are worn and new pads are needed. The sound
may come and go or be heard all the time your vehicle
is moving (except when you are pushing on the brake
pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in the
proper sequence to GM torque specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7
of this manual under Part C ªPeriodic Maintenance
Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you apply the brakes, with or without the
vehicle moving, your brakes adjust for wear.