2019 CADILLAC CT6 service

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) -
2019 - crc - 1/23/19
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) -
2019 - crc - 1/23/19
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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
VEHICLE CARE 319
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping your
foot on the regular brake, set the
parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
. To check the P (Park) mechanism's
holding ability: With the engine
running, shift to P (Park). Then
release the parking brake followed
by the regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
For the proper type and size, see
Maintenance Replacement Parts 0393. To replace the wiper blade assembly:
1. Pull the windshield wiper assembly away from the
windshield.
2. Lift up on the latch in the middleof the wiper blade where the
wiper arm attaches.
3. With the latch open, pull the wiper blade down toward the
windshield far enough to release
it from the J-hooked end of the
wiper arm.
4. Remove the wiper blade.
Caution
Allowing the wiper arm to touch
the windshield when no wiper blade
is installed could damage the
windshield. Any damage that occurs
would not be covered by the vehicle
warranty. Do not allow the wiper
arm to touch the windshield.
5. Reverse Steps 1–3 for wiper blade replacement.
Windshield Replacement
Head-Up Display (HUD) System
The windshield is part of the HUD
system. If the windshield must be
replaced, get one that is designed for
HUD or the HUD image may look out
of focus.
Driver Assistance Systems
When a windshield replacement is
needed and the vehicle is equipped
with a front-looking camera sensor for
the Driver Assistance Systems, the
windshield must be installed

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
320 VEHICLE CARE
according to GM specifications for
these systems to work properly. If it is
not, there may be unexpected
behavior and/or messages from these
systems.
Acoustic Windshield
The vehicle is equipped with an
acoustic windshield. If the windshield
needs to be replaced, be sure to get an
acoustic windshield so you will
continue to have the benefits an
acoustic windshield can provide.
Gas Strut(s)
This vehicle is equipped with gas
strut(s) to provide assistance in lifting
and holding open the hood/trunk/
liftgate system in full open position.
{Warning
If the gas struts that hold open the
hood, trunk, and/or liftgate fail, you
or others could be seriously injured.
Take the vehicle to your dealer for
service immediately. Visually(Continued)
Warning (Continued)
inspect the gas struts for signs of
wear, cracks, or other damage
periodically. Check to make sure the
hood/trunk/liftgate is held open
with enough force. If struts are
failing to hold the hood/trunk/
liftgate, do not operate. Have the
vehicle serviced.
Caution
Do not apply tape or hang any
objects from gas struts. Also do not
push down or pull on gas struts.
This may cause damage to the
vehicle.
See Maintenance Schedule 0383.
Hood
Trunk