2018 CADILLAC CT6 O star

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 311
Change the fluid and filter at the
intervals listed inMaintenance
Schedule 0390, and be sure to use the
fluid listed in Recommended Fluids and
Lubricants 0399.
Engine Air Cleaner/Filter
The engine air cleaner/filter is in the
engine compartment. See Engine
Compartment Overview 0300.
When to Inspect the Engine Air
Cleaner/Filter
For intervals on changing and
inspecting the engine air cleaner/filter,
see Maintenance Schedule 0390.
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
engine air cleaner/filter or
components with water or
compressed air.
To inspect or replace the engine air
cleaner/filter:2.0L L4 Gasoline Only Engine Shown,
2.0L L4 PLUG-IN Engine Similar
1. Remove the five screws on top of the engine air cleaner/filter cover.
2. Lift the engine air cleaner/filter cover open on the hinge.
3. Lift and remove the engine air cleaner/filter. 4. Inspect or replace the engine air
cleaner/filter.
5. Reverse Steps 1–3 to reinstall the engine air cleaner/filter cover.
3.0L V6 Engine
1. Remove the 10 screws on top of the engine air cleaner/filter cover
to gain access to both air
cleaner/filters.
2. Lift the engine air cleaner/filter cover open on the hinge.
3. Lift and remove one or both engine air cleaner/filters.
4. Inspect or replace one or both engine air cleaner/filters.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 313
3.0L V6 Engine
1. Engine Coolant Surge Tankand Pressure Cap
2. Engine Cooling Fan (Out of View)
3.6L V6 Engine
1. Engine Coolant Surge Tank
and Pressure Cap
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-11292458) -
2018 - crc - 2/15/17
316 VEHICLE CARE
2. Keep turning the pressure capslowly 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.
Cooling System
(PLUG-IN Only)
The cooling system allows the engine
and the Traction Power Inverter
Module (TPIM) to maintain the
correct working temperature.
1. Engine Coolant Surge Tank
and Pressure Cap
2. Traction Power Inverter Module (TPIM)
3. TPIM Coolant Reservoir and Pressure Cap
4. 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.
{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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
318 VEHICLE CARE
The coolant surge tank is in the
engine compartment on the passenger
side of the vehicle. SeeEngine
Compartment Overview 0300.
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 GM
Premix DEX-COOL coolant. Be sure
the cooling system, including the
coolant surge tank pressure cap, is
cool before this is done. See Engine
Overheating 0321.
{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.
1. Remove the coolant surge tank
pressure 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

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 319
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 caps are not secured
and tightened properly, coolant loss
and damage to the PLUG-IN cooling
(Continued)
Caution (Continued)
systems or vehicle may occur. Make
sure the caps are properly and
tightly secured.
PLUG-IN Coolant
The cooling system allows the TPIM
to maintain the correct working
temperature.
{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.
{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
(Continued)
Warning (Continued)
leak; all coolant could leak out.
That could cause an engine fire and
can burn you. Fix any leak before
driving the vehicle.
The TPIM is cooled using a separate
coolant loop.
The TPIM is kept below a maximum
temperature. If the temperature rises
above this temperature, the electric
cooling fan will turn on to cool the
coolant.
What to Use Caution
Do not use anything other than GM
Premix DEX-COOL coolant.
Anything else can cause damage to
the PLUG-IN cooling system
components and the vehicle, which
would not be covered by the vehicle
warranty.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 325
Stop/Start System
The vehicle has a Stop/Start system to
shut off the engine to help conserve
fuel.
SeeStarting the Engine (PLUG-IN Only)
0 218 orStarting the Engine (Gasoline
Only) 0221.
{Warning
WARNING: Battery posts,
terminals, and related accessories
contain lead and lead compounds,
chemicals known to the State of
California to cause cancer and birth
defects or other reproductive harm.
Batteries also contain other
chemicals known to the State of
California to cause cancer. WASH
HANDS AFTER HANDLING. For
more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See California Proposition 65 Warning
0 297 and the back cover.
PLUG-IN Vehicle
The PLUG-IN vehicle 12-volt battery is
in the trunk. PLUG-IN vehicles also
have a high voltage battery. Only a
trained service technician with the
proper knowledge and tools should
inspect, test, or replace the high
voltage battery. See your dealer if
either the 12-volt or the high voltage
battery needs service. The dealer has
information on how to recycle the
high voltage battery.
{Warning
Damage to the high voltage battery
or high voltage system can create a
risk of electric shock, overheating,
or fire.
If the vehicle is damaged from a
moderate to severe crash, flood,
fire, or other event, the vehicle
should be inspected as soon as
possible. Until the vehicle has been
inspected, store it outside at least
15 m (50 ft) from any structure or
(Continued)
Warning (Continued)
anything that can burn. Ventilate
the vehicle by opening a window or
a door.
Contact your dealer as soon as
possible to determine whether an
inspection is needed.
Vehicle Storage
{Warning
Batteries have acid that can burn
you and gas that can explode. You
can be badly hurt if you are not
careful. SeeJump Starting - North
America 0374 for tips on working
around a battery without
getting hurt.
Infrequent Usage: Remove the 12-volt
battery black, negative (−) cable from
the battery to keep the battery from
running down.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
326 VEHICLE CARE
Extended Storage: Remove the 12-volt
battery black, negative (−) cable from
the battery or use a battery trickle
charger.
Remember to reconnect the battery
when ready to drive the vehicle.
All-Wheel Drive
If the vehicle is equipped with
All-Wheel Drive (AWD), this is an
additional system that needs
lubrication.
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 Lubricant1. 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 0399.
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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 327
Automatic Transmission
Shift Lock Control Function
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. It should be
parked on a level surface.
2. Firmly apply the parking brake. See Electric Parking Brake 0235.
Be ready to apply the regular
brake immediately if the vehicle
begins to move.
3. With the engine off, turn the ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), 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.
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 0400.
To replace the wiper blade assembly: 1. Pull the windshield wiper assembly away from the
windshield.