2018 CADILLAC CT6 cooling

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
320 VEHICLE CARE
The coolant reservoir for the TPIM is
filled with GM Premix DEX-COOL
coolant. SeeRecommended Fluids and
Lubricants 0399. If using this mixture,
nothing else needs to be added.
The coolant needs to be replaced at
the appropriate interval. See
Maintenance Schedule 0390.
Checking Coolant
The vehicle must be on a level surface
when checking the coolant level.
The coolant reservoir is in the engine
compartment. See Engine Compartment
Overview 0300.
Check to see if coolant is visible in the
reservoir. If coolant is visible but the
coolant level is below the indicated
mark, there could be a leak in the
cooling system.
Caution
Do not run the engine when there
is a leak in the PLUG-IN cooling
system. This can cause a loss of all
coolant and can damage the system
and the vehicle. Have any leaks
fixed right away.
How to Add Coolant to the
Coolant Reservoir
If no problem is found, add the proper
DEX-COOL coolant mixture at the
coolant reservoir.
The coolant reservoir pressure cap can
be removed when the cooling system,
including the pressure cap, is no
longer hot.
1. Turn the pressure cap counterclockwise and remove it.
2. Fill the coolant reservoir with the proper mixture to the indicated
mark on the side of the reservoir.
3. Reinstall the pressure cap tightly.
Caution
If the pressure caps are not secured
and tightened properly, coolant loss
and damage to the PLUG-IN cooling
systems or vehicle may occur. Make
sure the caps are properly and
tightly secured.
Check the level in the coolant
reservoir when the cooling system has
cooled down. If the coolant is not at
the proper level, repeat Steps 1 and 2,
then reinstall the pressure cap. If the
coolant still is not at the proper level
when the system cools down again,
see your dealer.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 321
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.
SeeEngine Coolant Temperature Gauge
0 139 and Engine Coolant Temperature
Warning Light 0149. 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 0411.
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.
If No Steam Is Coming from the
Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen or
heard, the problem may not be too
serious. Sometimes the engine can get
a little too hot when the vehicle:
. Climbs a long hill on a hot day
. Stops after high-speed driving
. Idles for long periods in traffic
If the overheat warning is displayed
with no sign of steam: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral), and let the
engine idle.
If the engine coolant temperature
gauge is no longer in the overheated
area or the engine coolant
temperature warning light no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
322 VEHICLE CARE
for about 10 minutes. Keep a safe
distance from the vehicle in front.
If the warning does not come back on,
continue to drive normally and have
the cooling system checked for proper
fill and function.
If the warning continues, pull over,
stop, and park the vehicle right away.
If there is no sign of steam, idle the
engine for three minutes while parked.
If the warning is still displayed, turn
off the engine until it cools down.
Washer Fluid
What to Use
When windshield washer fluid is
needed, be sure to read the
manufacturer's instructions before
use. If operating the vehicle in an area
where the temperature may fall below
freezing, use a fluid that has sufficient
protection against freezing.
Adding Washer Fluid
Open the cap with the washer symbol
on it. Add washer fluid until the tank
is full. SeeEngine Compartment
Overview 0300 for reservoir location.
Caution
.
Do not use washer fluid that
contains any type of water
repellent coating. This can
cause the wiper blades to
chatter or skip.
. Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system
and paint.
. Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
(Continued)
Caution (Continued)
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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/15/17
VEHICLE CARE 359
Wheel Alignment and Tire
Balance
The tires and wheels were aligned and
balanced at the factory to provide the
longest tire life and best overall
performance. Adjustments to wheel
alignment and tire balancing are not
necessary on a regular basis. Consider
an alignment check if there is unusual
tire wear or the vehicle is significantly
pulling to one side or the other. Some
slight pull to the left or right,
depending on the crown of the road
and/or other road surface variations
such as troughs or ruts, is normal.
If the vehicle is vibrating when driving
on a smooth road, the tires and
wheels may need to be rebalanced.
See your dealer for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked, or badly rusted or corroded.
If wheel nuts keep coming loose, the
wheel, wheel bolts, and wheel nuts
should be replaced. If the wheel leaks
air, replace it. Some aluminum wheels
can be repaired. See your dealer if any
of these conditions exist.Your dealer will know the kind of
wheel that is needed.
Each new wheel should have the same
load-carrying capacity, diameter,
width, offset, and be mounted the
same way as the one it replaces.
Replace wheels, wheel bolts, wheel
nuts, or Tire Pressure Monitor System
(TPMS) sensors with new GM original
equipment parts.
{Warning
Using the wrong replacement
wheels, wheel bolts, or wheel nuts
can be dangerous. It could affect
the braking and handling of the
vehicle. Tires can lose air, and
cause loss of control, causing a
crash. Always use the correct wheel,
wheel bolts, and wheel nuts for
replacement.
Caution
The wrong wheel can also cause
problems with bearing life, brake
cooling, speedometer or odometer
calibration, headlamp aim, bumper
height, vehicle ground clearance,
and tire or tire chain clearance to
the body and chassis.
Used Replacement Wheels
{Warning
Replacing a wheel with a used one
is dangerous. How it has been used
or how far it has been driven may
be unknown. It could fail suddenly
and cause a crash. When replacing
wheels, use a new GM original
equipment wheel.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
390 SERVICE AND MAINTENANCE
Cadillac Premium Care
Maintenance
Your vehicle comes with the Cadillac
Premium Care Maintenance. It is a
maintenance program that covers
select maintenance services during
the first three years or 58 000 km
(36,000 mi) whichever comes first.
Cadillac Premium Care Maintenance
covers routine maintenance services,
when scheduled in accordance with
the owner’s manual, including:
.Oil changes based on the vehicle's
oil life monitor system.
. Tire rotation every 12 000 km
(7,500 mi).
. Passenger compartment air filter
replacement.
. Multi-point vehicle inspection
(MPVI) performed by a qualified
technician.
Cadillac requires that all Cadillac
Premium Care Maintenance services
be performed by a Cadillac authorized
service dealer.
Maintenance Schedule
Owner Checks and Services
At Each Fuel Stop
. Check the engine oil level. See
Engine Oil 0307.
Once a Month
. Check the tire inflation pressures.
See Tire Pressure 0347.
. Inspect the tires for wear. See Tire
Inspection 0353.
. Check the windshield washer fluid
level. See Washer Fluid 0322.
Engine Oil Change
When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km/600 mi. If driven
under the best conditions, the engine
oil life system may not indicate the
need for vehicle service for up to a
year. The engine oil and filter must be
changed at least once a year and the
oil life system must be reset. Your
trained dealer technician can perform
this work. If the engine oil life system is reset accidentally, service the
vehicle within 5 000 km/3,000 mi since
the last service. Reset the oil life
system when the oil is changed. See
Engine Oil Life System
0309.
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi
Rotate the tires, if recommended for
the vehicle, and perform the following
services. See Tire Rotation0353.
. Check engine oil level and oil
life percentage. If needed, change
engine oil and filter, and reset oil
life system.
See Engine Oil 0307 and Engine Oil
Life System 0309.
. Check engine coolant level.
See Cooling System (Gasoline Only)
0 312 orCooling System (PLUG-IN
Only) 0316.
. Check windshield washer fluid
level. See Washer Fluid 0322.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-11292458) -
2018 - crc - 2/14/17
392 SERVICE AND MAINTENANCE
Maintenance Schedule
Additional Required Services -
Normal12 000 km/7,500 mi
24 000 km/15,000 mi
36 000 km/22,500 mi
48 000 km/30,000 mi
60 000 km/37,500 mi
72 000 km/45,000 mi
84 000 km/52,500 mi
96 000 km/60,000 mi
108 000 km/67,500 mi
120 000 km/75,000 mi
132 000 km/82,500 mi
144 000 km/90,000 mi
156 000 km/97,500 mi
168 000 km/105,000 mi
180 000 km/112,500 mi
192 000 km/120,000 mi
204 000 km/127,500 mi
216 000 km/135,000 mi
228 000 km/142,500 mi
240 000 km/150,000 mi
Rotate tires, if recommended for the vehicle, and
perform Required Services. Check engine oil level
and oil life percentage. Change engine oil and filter,
if needed. (1)@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
Inspect evaporative control system. (3)@ @@
Replace engine air cleaner filter. (4)@@@
Replace spark plugs. Inspect spark plug wires. (2.0L
and 3.0L Twin Turbo Engines)@ @
Replace spark plugs. Inspect spark plug wires. (3.6L
Engine Only)@
Drain and fill engine cooling system and Power
Electronics cooling system. (5)@
Change transfer case fluid, if equipped with
AWD. (6)@
Change rear axle fluid.@
Visually inspect accessory drive belts. (7)@
Replace brake fluid. (8)