service CADILLAC CT6 2019 Repair Manual

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 291
If equipped with remote vehicle start,
open the hood before performing any
service work to prevent remote
starting the vehicle accidentally. See
Remote Vehicle Start036.
Keep a record with all parts receipts
and list the mileage and the date of
any service work performed. See
Maintenance Records 0395.
Caution
Even small amounts of
contamination can cause damage to
vehicle systems. Do not allow
contaminants to contact the fluids,
reservoir caps, or dipsticks.
Hood
{Warning
Gas struts and other metal
components under the hood can get
hot after running the engine. Do
not touch these components as
they can burn unprotected skin and
could cause serious injury. Clear any snow from the hood before
opening.
To open the hood:
1. Pull the hood release handle. It is
on the lower left side of the
instrument panel between the
door and the steering wheel.
2. Release the handle, then pull the handle again to fully open
the hood.
3. Go to the front of the vehicle and lift the hood open.
Caution
Be sure the hood is completely
closed before driving. Damage may
occur if it is not.
To close the hood: 1. Before closing the hood, be sure all filler caps are properly
installed.
2. Lower the hood approximately 46 cm (18 in) from the closed
position.
3. Then push the front center of the hood with a swift, firm motion.
4. Check to make sure the hood is closed. If not, release the hood
from inside and repeat Steps 1–3.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
300 VEHICLE CARE
Follow these guidelines:
.To get an accurate reading, park
the vehicle on level ground. Check
the engine oil level after the
engine has been off for at least
two hours. Checking the engine oil
level on steep grades or too soon
after engine shutoff can result in
incorrect readings. Accuracy
improves when checking a cold
engine prior to starting. Remove
the dipstick and check the level.
. If unable to wait two hours, the
engine must be off for at least
15 minutes if the engine is warm,
or at least 30 minutes if the
engine is not warm. Pull out the
dipstick, wipe it with a clean paper
towel or cloth, then push it back
in all the way. Remove it again,
keeping the tip down, and check
the level.When to Add Engine Oil
2.0L L4 Turbo (LSY) and 4.2L V8 Twin
Turbo (LTA) Engines
3.0L V6 Twin Turbo (LGW) and 3.6L V6 (LGX) Engines
If the oil is below the cross-hatched
area at the tip of the dipstick and the
engine has been off for at least
15 minutes, add 1 L (1 qt) of the
recommended oil and then recheck
the level. See “Selecting the Right
Engine Oil” later in this section for an
explanation of what kind of oil to use.
For engine oil crankcase capacity, see
Capacities and Specifications 0397.
Caution
Do not add too much oil. Oil levels
above or below the acceptable
operating range shown on the
dipstick are harmful to the engine.
If the oil level is above the
operating range (i.e., the engine has
so much oil that the oil level gets
above the cross-hatched area that
shows the proper operating range),
the engine could be damaged. Drain
the excess oil or limit driving of the
vehicle, and seek a service
professional to remove the
excess oil.
See Engine Compartment Overview
0 292 for the location of the engine oil
fill cap.
Add enough oil to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when through.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
302 VEHICLE CARE
When selecting an oil of the
appropriate viscosity grade, it is
recommended to select an oil of the
correct specification. See
“Specification”earlier in this section.
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. Never
dispose 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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
304 VEHICLE CARE
Engine Air Filter Life
System
If equipped, this feature provides an
indication of when to change the
engine air filter. It is based on driving
conditions, which can cause when to
change to vary greatly. It is possible
an air filter change may not be
indicated for up to four years.
When to Change Engine Air
Filter
Replace the engine air filter when the
REPLACE NOW message displays on
the Driver Information Center (DIC).
This should be done as soon as
possible within the next 1 000 km
(600 mi) or at the next oil change,
depending on the DIC message. The
system must be reset after the engine
air filter is changed. See your dealer
for service and to reset the system.
When a REPLACE AT NEXT OIL
CHANGE message displays, this
indicates that the engine air filter
change is necessary at the next engine
oil change.
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. Select Engine Air Filter Life on the DIC menu. See Driver
Information Center (DIC) 0150.
3. Press
Tto move to the Reset/
Disable display area. Select Reset
then press SEL. Then press Yes
to confirm the reset.
4. 100% Air Filter Life will be displayed when the Engine Air
Filter Life System is successfully
reset.
Engine Air Cleaner/Filter
The engine air cleaner/filter is in the
engine compartment. See Engine
Compartment Overview 0292.
When to Inspect the Engine Air
Cleaner/Filter
.
For intervals on changing and
inspecting the engine air filter, see
Maintenance Schedule 0383.
. If equipped with Engine Air Filter
Life System, see Engine Air Filter
Life System 0304.
. If driving in very dusty areas,
follow the engine air filter
inspecting and changing intervals,
see Maintenance Schedule 0383.
How to Inspect 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. Remove the
engine air cleaner/filter. Lightly tap
and shake the engine air cleaner/filter
(away from the vehicle), to release
loose dust and dirt. Inspect the engine
air cleaner/filter for damage, and
replace if damaged. Do not clean the

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
308 VEHICLE CARE
3.6L V6 Engine
1. Engine Coolant Surge Tankand Pressure Cap (Under
Cover)
2. Engine Cooling Fan (Out of View)
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
cold fill 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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
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VEHICLE CARE 309
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. SeeMaintenance
Schedule 0383.
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 0312.
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. 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.
3.0L V6 Engine Coolant Surge Tank

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
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VEHICLE CARE 311
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.
If the coolant still is not at the
proper level when the system
cools down again, see your
dealer.
Caution
If the pressure cap is not tightly
installed, coolant loss and engine
damage may occur. Be sure the cap
is properly and tightly secured.
2.0L L4 Engine Only - Automatic
Coolant Service Fill Instructions
If equipped, this feature assists in
filling and removing air from the
cooling system after service of
components or when coolant is added
after being too low.
To activate the fill and air removal
process:
1. With a cold system, add coolant to the COLD FILL mark on the
surge tank.
2. Replace the cap on the surge tank.
3. Connect the vehicle to a battery charger.
4. Turn the ignition to Service Mode. See Ignition Positions
0 201.
5. Turn off the air conditioning.
6. Set the parking brake.
7. At the same time, press the accelerator and the brake for
two seconds, then release.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
312 VEHICLE CARE
At the end of the cycle, check the
coolant level in the surge tank and
add coolant if it is low. Turn off the
vehicle, allow the Electronic Control
Module (ECM) to go to sleep, about
2 minutes, and repeat Steps 4-7.
Listen for pump activation and
movement of the control valves while
watching the level of the coolant in
the surge tank. If the tank empties,
turn the ignition off, carefully remove
the surge tank cap, refill to the COLD
FILL mark, and repeat Steps 4-7. The
fill and air removal process will run
for approximately 10 minutes.
4.2L V8 Engine OnlyCaution
This vehicle has a specific coolant
fill procedure. Failure to follow this
procedure could cause the engine to
overheat and be severely damaged.
See your dealer for assistance.
Because of possible engine failure or
damage if performed without the
proper tools and information, engine coolant should only be added
by a qualified technician. See your
dealer.
Engine Overheating
The vehicle has several indicators to
warn of the engine overheating.
There is an engine coolant
temperature gauge and an engine
coolant temperature warning light on
the instrument cluster. See
Engine
Coolant Temperature Gauge 0135 and
Engine Coolant Temperature Warning
Light 0146. The vehicle may also
display a message on the Driver
Information Center (DIC).
If the decision is made not to lift the
hood when this warning appears, get
service help right away. See Roadside
Service 0405.
If the decision is made to lift the
hood, make sure the vehicle is parked
on a level surface. Then check to see if
the engine cooling fan is running.
If the engine is overheating, the fan
should be running. If it is not, do not
continue to run the engine. Have the
vehicle serviced.
Caution
Do not run the engine if there is a
leak in the engine cooling system.
This can cause a loss of all coolant
and can damage the system and
vehicle. Have any leaks fixed
right away.
If Steam Is Coming from the
Engine Compartment
{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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
314 VEHICLE CARE
Caution (Continued)
.Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
to freeze and damage the
washer fluid tank and other
parts of the washer system.
. When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
. Fill the washer fluid tank only
three-quarters full when it is
very cold. This allows for
fluid expansion if freezing
occurs, which could damage
the tank if it is
completely full.
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 can come and go or can be heard all the time when the vehicle is
moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound
means that soon the brakes will not
work well. That could lead to a
crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Caution
Continuing to drive with worn-out
brake pads could result in costly
brake repair.
Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the 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 torque
specifications. See
Capacities and
Specifications 0397.
Brake pads should always be replaced
as complete axle sets.
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 that brake
service may be required.
Replacing Brake System Parts
Always replace brake system parts
with new, approved replacement parts.
If this is not done, the brakes may not
work properly. The braking
performance expected can change in
many other ways if the wrong
replacement brake parts are installed
or if parts are improperly installed.
Electric Brake Boost
If equipped, this vehicle may have an
electrically boosted power braking
system. The system works with the

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
318 VEHICLE CARE
Transfer Case
When to Check Lubricant
It is not necessary to regularly check
the transfer case fluid unless a leak is
suspected or an unusual noise is
heard. A fluid loss could indicate a
problem. Have it inspected and
repaired.
How to Check Lubricant
1. Fill Plug
2. Drain Plug
To get an accurate reading, the vehicle
should be on a level surface.If the level is below the bottom of the
fill plug hole on the transfer case,
some lubricant will need to be added.
Add enough lubricant to raise the
level to the bottom of the fill plug
hole. Use care not to overtighten the
fill plug.
What to Use
To determine what kind of lubricant
to use, see
Recommended Fluids and
Lubricants 0392.
Starter Switch Check
{Warning
When you are doing this inspection,
the vehicle could move suddenly.
If the vehicle moves, you or others
could be injured.
1. Before starting this check, be sure there is enough room
around the vehicle. 2. Firmly apply both the parking
brake and the regular brake. Do
not use the accelerator pedal,
and be ready to turn off the
engine immediately if it starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check, the
vehicle could begin to move. You or
others could be injured and
property could be damaged. Make
sure there is room in front of the
vehicle in case it begins to roll. Be
ready to apply the regular brake at
once should the vehicle begin
to move.