2003 CADILLAC CTS engine

6-13 What Kind of Engine Oil to Use
Oils recommended for your vehicle can be identified by
looking for the starburst symbol.
This symbol indicates that the oil has been certified by
the American Petroleum Institute (API). Do not use any
oil which does not carry this starburst symbol.
If you change your own
oil, be sure you use oil
that has the starburst
symbol on the front of the
oil container. If you have
your oil changed for you,
be sure the oil put into
your engine is American
Petroleum Institute certified
for gasoline engines.
You should also use the proper viscosity oil for your
vehicle, as shown in the viscosity chart.
SAE 10W
-30 is best for your vehicle. However, you can
use SAE 5W
-30 if it's going to be colder than 60
F
(16
C) before your next oil change. When it's very cold,
you should use SAE 5W
-30. These numbers on an oil
container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
-50.

6-14
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
starburst symbol. Failure to use the
recommended oil can result in engine damage not
covered by your warranty.
GM Goodwrench
oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W
-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for good
performance and engine protection.
When to Change Engine Oil
(GM Oil Life System)
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based
on engine revolutions and engine temperature, and not
on mileage. Based on driving conditions, the mileage
at which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A Change Engine Oil message in the DIC
will come on. Change your oil as soon as possible
within the next two times you stop for fuel. 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
filter must be changed at least once a year and at this
time the system must be reset. 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.

6-15
How to Reset the Change Engine Oil Message and
the Oil Life Indicator
The GM Oil Life System
calculates when to change
your engine oil and filter 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 message in the DIC being turned on, reset
the system.
After the oil has been changed, the Change Engine
Oil message and the oil life indicator must be reset.
To reset the message and indicator, use one of the
following procedures:Base Audio System
Press the CLR button located to the right of the DIC
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. Press the up or down arrow on the INFO button
located to the right of the DIC display to access the
DIC menu.
2. Once XXX% ENGINE OIL LIFE menu item is
highlighted, press and hold the CLR button.
The percentage will return to 100, and the oil life
indicator will be reset.
3. Repeat the steps if the percentage does not
return to 100.

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.

6-17
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.