2020 CADILLAC CT6 Owner's Manual

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
280 VEHICLE CARE
Engine Oil Additives/Engine Oil
Flushes
Do not add anything to the oil. The
recommended oils meeting the dexos
specification are all that is needed for
good performance and engine
protection.
Engine oil system flushes are not
recommended and could cause engine
damage not covered by the vehicle
warranty.
What to Do with Used Oil
Used engine oil contains certain
elements that can 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 filter before disposal. Neverdispose of oil by putting it in the trash
or pouring it on the ground, into
sewers, or into streams or bodies of
water. Recycle it by taking it to a place
that collects used oil.
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system
that indicates when to change the
engine oil and filter. This is based on a
combination of factors which include
engine revolutions, engine
temperature, and miles driven. Based
on driving conditions, the mileage at
which an oil change is indicated can
vary considerably. For the oil life
system to work properly, the system
must be reset every time the oil is
changed.
When the system has calculated that
oil life has been diminished, it
indicates that an oil change is
necessary. A CHANGE ENGINE OIL
SOON message comes on. Change the
oil as soon as possible within the next
1 000 km (600 mi). It is possible that,
if driving under the best conditions,the oil life system might indicate that
an oil change is not necessary for up
to a year. The engine oil and filter
must be changed at least once a year
and at this time the system must be
reset. Your dealer has trained service
people who will perform this work and
reset the system. It is also important
to check the oil regularly over the
course of an oil drain interval and
keep it at the proper level.
If the system is ever reset accidentally,
the oil must be changed at 5 000 km
(3,000 mi) since the last oil change.
Remember to reset the oil life system
whenever the oil is changed.
How to Reset the Engine Oil Life
System
Reset the system whenever the engine
oil is changed so that the system can
calculate the next engine oil change.
To reset the system:
1. Using the DIC buttons, display REMAINING OIL LIFE on the
DIC. See Driver Information Center
(DIC) 0132.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 281
2. Press and hold SEL to clear theCHANGE ENGINE OIL SOON
message and reset the oil life
at 100%.
Be careful not to reset the oil life
display accidentally at any time
other than after the oil is
changed. It cannot be reset
accurately until the next oil
change.
The oil life system can also be reset as
follows: 1. Using the DIC buttons, display REMAINING OIL LIFE on the
DIC. See Driver Information Center
(DIC) 0132.
2. Fully press and release the accelerator pedal three times
within five seconds.
If the CHANGE ENGINE OIL
SOON message is not on, the
system is reset.
The system is reset when the
CHANGE ENGINE OIL SOON message
is off. If the CHANGE ENGINE OIL SOON
message comes back on when the
vehicle is started, the engine oil life
system has not been reset. Repeat the
procedure.
Automatic Transmission
Fluid
How to Check 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 the vehicle to your dealer and
have it repaired as soon as possible.
The vehicle is not equipped with a
transmission fluid level dipstick.
There is a special procedure for
checking and changing the
transmission fluid. Because this
procedure is difficult, this should be
done at the dealer. Contact your dealer
for additional information.
Caution
Use of the incorrect automatic
transmission fluid may damage the
vehicle, and the damage may not be
covered by the vehicle warranty.
Always use the correct automatic
transmission fluid. See
Recommended Fluids and Lubricants
0
368.
Change the fluid and filter at the
intervals listed in Maintenance
Schedule 0359, and be sure to use the
fluid listed in Recommended Fluids and
Lubricants 0368.
Engine Air Filter Life
System
If equipped, this feature provides the
engine air filter's remaining life and
best timing for a change. The timing
to change an engine air filter depends
on driving and environmental
conditions.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
282 VEHICLE CARE
When to Change the Engine Air
Filter
When the Driver Information Center
(DIC) displays a message to replace
the engine air filter at the next oil
change, follow this timing.
When the DIC displays a message to
replace the engine air filter soon,
replace the engine air filter at the
earliest convenience.
The system must be reset after the
engine air filter is changed.
If the DIC displays a message to check
the engine air filter system, see your
dealer.
How to Reset Engine Air Filter
Life System
Reset the system whenever the engine
air filter is replaced so that the system
can calculate the next engine air filter
change.To reset:
1. Place the vehicle in P (Park).
2. Display the Air Filter Life on the DIC. See Driver Information Center
(DIC) 0132.
3. Press
Ton the steering wheel to
move to the Reset/Disable
display area. Select Reset, then
press SEL.
4. Press SEL to confirm the reset.
Engine Air Cleaner/Filter
The engine air cleaner/filter is in the
engine compartment. See Engine
Compartment Overview 0274.
When to Inspect the Engine Air
Cleaner/Filter
.
For intervals on changing and
inspecting the engine air cleaner/
filter, see Maintenance Schedule
0 359.
. If equipped with Engine Air Filter
Life System, see Engine Air Filter
Life System 0281.
. If driving in very dusty areas,
follow the engine air filter
inspecting and changing intervals,
see Maintenance Schedule 0359.
How to Inspect/Replace the
Engine Air Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/filter,
make sure that the engine air cleaner/
filter housing and nearby components
are free of dirt and debris. Do not
clean the engine air cleaner/filter or
components with water or
compressed air.

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2020 - CRC - 6/11/19
VEHICLE CARE 283
To inspect or replace the engine air
cleaner/filter:
3.6L V6 Engine
1. Screws (6)
2. Bolts (3)
3. Diagonal Brace
1. Remove the three bolts (2) andthe diagonal brace (3).
2. Remove the six screws (1) on top of the engine air cleaner/filter
cover.
3. Lift the engine air cleaner/filter cover open on the hinge.
4. Lift and remove the engine air cleaner/filter. 5. Inspect or replace the engine air
cleaner/filter.
6. Reverse Steps 1–4 to reinstall the engine air cleaner/filter cover
and diagonal brace.
7. If equipped, reset the engine air filter life system after replacing
the engine air filter. See Engine
Air Filter Life System 0281.
4.2L V8 Engine (Driver Side)
1. Diagonal Brace
2. Bolts (3)
3. Screws (4)
1. Remove the three bolts (2) and
the diagonal brace (1).
2. Remove the four screws (3) on top of the engine air cleaner/
filter cover.
3. Lift the engine air cleaner/filter cover open on the hinge.
4. Lift and remove the engine air cleaner/filter.
5. Inspect or replace the engine air cleaner/filter.
6. Reverse Steps 1–4 to reinstall the engine air cleaner/filter cover
and diagonal brace.
7. If equipped, reset the engine air filter life system after replacing
the engine air filter. See Engine
Air Filter Life System 0281.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
284 VEHICLE CARE
4.2L V8 Engine (Passenger Side)
1. Screws (4)
2. Bolts (3)
3. Diagonal Brace
1. Remove the three bolts (2) andthe diagonal brace (3).
2. Remove the four screws (1) on top of the engine air cleaner/
filter cover.
3. Lift the engine air cleaner/filter cover open on the hinge.
4. Lift and remove the engine air cleaner/filter.
5. Inspect or replace the engine air cleaner/filter. 6. Reverse Steps 1–4 to reinstall the
engine air cleaner/filter cover
and diagonal brace.
7. If equipped, reset the engine air filter life system after replacing
the engine air filter. See Engine
Air Filter Life System 0281.
{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. Use caution
when working on the engine. Do
not start the engine or drive the
vehicle with the air cleaner/filter
off, as flames may be present if the
engine backfires.
Caution
If the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always have
the air cleaner/filter in place when
driving.
Cooling System
The cooling system allows the engine
to maintain the correct working
temperature.
3.6L V6 Engine
1. Engine Coolant Surge Tank
and Pressure Cap (Under
Cover)
2. Engine Cooling Fan (Out of View)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 285
4.2L V8 Engine
1. Engine Coolant Surge Tankand Pressure Cap (Under
Cover)
2. Engine Cooling Fan (Out of View)
{Warning
An underhood electric fan can start
up even when the engine is not
running and can cause injury. Keep
hands, clothing, and tools away
from any underhood electric fan. If the coolant inside the coolant surge
tank is boiling, do not do anything
else until it cools down. The vehicle
should be parked on a level surface.
The coolant level should be at the
indicated mark on the middle of the
tank. If it is not, the vehicle may have
a leak at the radiator hoses, heater
hoses, radiator, water pump,
or somewhere else in the cooling
system.
{Warning
Do not touch heater or radiator
hoses, or other engine parts. They
can be very hot and can burn you.
Do not run the engine if there is a
leak; all coolant could leak out.
That could cause an engine fire and
can burn you. Fix any leak before
driving the vehicle.
If there seems to be no leak, with the
engine on, check to see if the electric
cooling fan is running. If the engine is
overheating, the fan should be
running. If it is not, the vehicle needs
service. Turn off the engine.
Engine Coolant
The engine cooling system in the
vehicle is filled with a DEX-COOL
engine coolant mixture. This coolant
needs to be checked and replaced at
appropriate intervals. See Maintenance
Schedule 0359.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating, see
Engine Overheating 0288.
What to Use
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain
water or the wrong mixture, the
engine could get too hot but there
would not be an overheat warning.
The engine could catch fire and you
or others could be burned.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
286 VEHICLE CARE
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture, nothing
else needs to be added. This mixture:
.Gives freezing protection down to
−37 °C (−34 °F), outside
temperature.
. Gives boiling protection up to
129 °C (265 °F), engine
temperature.
. Protects against rust and
corrosion.
. Will not damage aluminum parts.
. Helps keep the proper engine
temperature.
Caution
Do not use anything other than a
mix of DEX-COOL coolant that
meets GM Standard GMW3420 and
clean, drinkable water. Anything
else can cause damage to the
engine cooling system and the
vehicle, which would not be covered
by the vehicle warranty. Never dispose of engine coolant by
putting it in the trash, pouring it on
the ground, or into sewers, streams,
or bodies of water. Have the coolant
changed by an authorized service
center, familiar with legal
requirements regarding used coolant
disposal. This will help protect the
environment and your health.
Checking Coolant
The vehicle must be on a level surface
when checking the coolant level.
3.6L V6 and 4.2L V8 Engine Coolant
Surge Tank The coolant surge tank is in the
engine compartment on the passenger
side of the vehicle. See
Engine
Compartment Overview 0274.
Check to see if coolant is visible in the
coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, do not do anything else until
it cools down. See Engine Overheating
0 288.
How to Add Coolant to the
Coolant Surge Tank
If no problem is found, check to see if
coolant is visible in the coolant surge
tank. If coolant is visible but not at or
above the indicated mark, add a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant. Be sure
the cooling system, including the
coolant surge tank pressure cap, is
cool before this is done. See Engine
Overheating 0288.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 287
{Warning
Spilling coolant on hot engine parts
can burn you. Coolant contains
ethylene glycol and it will burn if
the engine parts are hot enough.
{Warning
Steam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure cap,
even a little, can cause them to
come out at high speed and you
could be burned. Never turn the cap
when the cooling system, including
the pressure cap, is hot. Wait for
the cooling system and pressure
cap to cool.
Caution
Failure to follow the specific
coolant fill procedure could cause
the engine to overheat and could
cause system damage. If coolant is
not visible in the surge tank,
contact your dealer.
3.6L V6 Engine
1. Remove the coolant surge tankpressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about
one-quarter of a turn. If you hear
a hiss, wait for that to stop. This will allow any pressure still left
to be vented out the
discharge hose.
2. Keep turning the pressure cap slowly and remove it.
3. Fill the coolant surge tank with the proper mixture to the
indicated level mark.
4. With the coolant surge tank pressure cap off, start the engine
and let it run until you can feel
the upper radiator hose getting
hot. Watch out for the engine
cooling fan.
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge
tank until the level reaches the
indicated level mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6.