engine coolant CADILLAC CT6 2020 User Guide

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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
288 VEHICLE CARE
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.
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 0119 and
Engine Coolant Temperature Warning
Light 0129. 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 0380.
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-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 289
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
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. See
Engine Compartment
Overview 0274 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.
(Continued)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 301
FusesUsage
26 Engine control module ignition
27 Steering column lock ignition
28 Rear heated seats ignition
29 Front heated seats ignition
30 –
31 Headlamp/Daytime running lamps/Right
headlamp
32 –
33 –
34 –
35 Engine control module ignition –2
36 Engine control module ignition –1
37 Coolant pump/ Ignition coils –odd
38 Ignition coils –even/
Non walk 2 Fuses
Usage
39 Non walk
40 Electric brake control module1/Instrument
cluster/central
gateway module
ignition
41 –
42 Fuel tank zone module/Ignition
43 Heated steering wheel module/
Reflective light aux
display/HVAC IGN/
Automatic occupant
sensing display
44 Aeroshutter
45 Washer
46 Front short range radar sensors
47 Left cornering LED
54 –
55 –
56 – Fuses
Usage
57 –
58 –
59 –
60 Antilock brake system pump/Electric
brake control
module–1
61 Front wiper
62 Headlamp leveling
63 –
64 –
66 Transfer case control module
67 –
68 –
69 –
70 –
71 Antilock brake system valve
72 –
73 –

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
306 VEHICLE CARE
FusesUsage
F26 Charge air coolant pump
F27 Engine control module ignition –2
F28 –
F29 –
Relays Usage
R1 Headlamp/Daytime running lamps
R2 Air conditioning control
R3 Starter motor
R4 Starter pinion
R5 Cabin heater pump
R6 Engine control module
R7 –
R8 –Instrument Panel Fuse
Block
The instrument panel fuse block is
behind the driver side instrument
panel storage compartment.
The storage compartment has a press
to open latch. To access the fuses,
open the compartment by pressing
and releasing near the top center
square.
Apply pressure to the two retaining
tabs on the sides of the compartment,
until the two retaining tabs clear the
sides of the instrument panel. Allow
the compartment to move downward,
and out of the way.
To reinstall the compartment, reverse
the steps.
The vehicle may not be equipped with
all of the fuses shown.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
SERVICE AND MAINTENANCE 359
Maintenance Schedule
Owner Checks and Services
Check the engine oil level. SeeEngine
Oil 0277.
Once a Month
. Check the tire inflation pressures.
See Tire Pressure 0322.
. Inspect the tires for wear. See Tire
Inspection 0329.
. Check the windshield washer fluid
level. See Washer Fluid 0289.
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
0280.
Engine Air Filter Change
When the REPLACE AT NEXT OIL
CHANGE message displays, the engine
air filter should be replaced at the
next engine oil change. When the
REPLACE ENGINE AIR FILTER SOON
message displays, the engine air filter
should be replaced at the earliest
convenience. Reset the engine air
filter life system after the engine air
filter is replaced. See Engine Air Filter
Life System 0281.
Air Conditioning Desiccant
(Replace Every Seven Years)
The air conditioning system requires
maintenance every seven years. This
service requires replacement of the
desiccant to help the longevity and
efficient operation of the air
conditioning system. This service can
be complex. See your dealer.
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 Rotation0329.
. Check engine oil level and oil
life percentage. If needed,
change engine oil and filter,
and reset oil life system. See
Engine Oil 0277 and
Engine Oil Life System 0280.
. If equipped with the engine air
filter life system, check the air
filter life percentage. If necessary,
replace the engine air filter and
reset the engine air filter life
system. See Engine Air Filter Life
System 0281. If the vehicle is not
equipped with the engine air filter
life system, inspect the engine air
cleaner filter. See Engine Air
Cleaner/Filter 0282.
. Check engine coolant level. See
Cooling System 0284.
. Check windshield washer fluid
level. See Washer Fluid 0289.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
368 SERVICE AND MAINTENANCE
Recommended Fluids, Lubricants, and Parts
Recommended Fluids and Lubricants
UsageFluid/Lubricant
Automatic Transmission DEXRON-ULV Automatic Transmission Fluid (GM Part No. 19352619, in Canada 19352620).
Engine Coolant 50/50 mixture of clean drinkable water and use only DEX-COOL Coolant.
Engine Oil (3.6L V6 Engine) Engine oil meeting the dexos1 specification of the proper SAE viscosity grade. ACDelco dexos1 full synthetic is recommended. See Engine Oil0277.
Engine Oil (4.2L V8 Twin Turbo Engine) Engine oil meeting the dexos2 specification of the proper SAE viscosity grade. ACDelco dexos2 is recommended. SeeEngine Oil0277.
Hood Latch Assembly, Pivots, Spring Anchor, and Release Pawl Lubriplate Lubricant Aerosol (GM Part No. 89021668, in Canada 89021674) or
lubricant meeting requirements of NLGI #2, Category LB or GC-LB.
Hydraulic Brake System DOT 3 Hydraulic Brake Fluid (GM Part No. 19353126, in Canada 19353127).
Key Lock Cylinders, Hood and Door Hinges Multi-Purpose Lubricant, Superlube (GM Part No. 12346241, in
Canada 10953474).
Rear Axle (Except V-Series)/Front Axle SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88863089, in Canada 88863090).
Rear Axle (V-Series) SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88862624, in
Canada 88862625).
Transfer Case (All-Wheel Drive) Transfer Case Fluid (GM Part No. 19331044, in Canada 19331045).

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
402 INDEX
Climate Control SystemsAutomatic . . . . . . . . . . . . . . . . . . . . 158, 163
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Cluster, Instrument . . . . . . . . . . . .110, 113
Collision Damage Repair . . . . . . . . . . . 383
Compact Spare Tire . . . . . . . . . . . . . . . . . 342
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Connected Services Connections . . . . . . . . . . . . . . . . . . . . . . . 398
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . 399
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . 397
Connections Connected Services . . . . . . . . . . . . . . . 398
Control
Traction and ElectronicStability . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Control of a Vehicle . . . . . . . . . . . . . . . . 173
Convenience Net . . . . . . . . . . . . . . . . . . . . 101
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . 33
Coolant Engine Temperature Gauge . . . . . . 119
Engine Temperature WarningLight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Cooling . . . . . . . . . . . . . . . . . . . . . . . . .158, 163
Cooling System . . . . . . . . . . . . . . . . . . . . . 284
Cornering Lamps . . . . . . . . . . . . . . . . . . . 153 Courtesy Lamps . . . . . . . . . . . . . . . . . . . . . 154
Courtesy Transportation
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . 209 Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Cruise Control, Adaptive . . . . . . . . . . . 211
Cruise Control, Super . . . . . . . . . . . . . . . 220
Cupholders . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Customer Assistance . . . . . . . . . . . . . . . 378 Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Text Telephone (TTY) Users . . . . . 378
Customer Information Publications OrderingInformation . . . . . . . . . . . . . . . . . . . . . . 385
Customer Satisfaction Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 376
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . 387
D
Damage Repair, Collision . . . . . . . . . . . 383
Danger, Warning, and Caution . . . . . . . . 2
Data Collection Infotainment System . . . . . . . . . . . . . 389
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
Data Recorders, Event . . . . . . . . . . . . . . 388
Daytime Running Lamps (DRL) . . . 151
Defensive Driving . . . . . . . . . . . . . . . . . . . 173
Delayed Locking . . . . . . . . . . . . . . . . . . . . . 21 Diagnostics
Connected Services . . . . . . . . . . . . . . . 399
Distracted Driving . . . . . . . . . . . . . . . . . . 172
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . 154
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . . . . . 132
Delayed Locking . . . . . . . . . . . . . . . . . . . . 21
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . 21
Rear Seat Pass-Through . . . . . . . . . . . . 57
Drive Belt Routing, Engine . . . . . . . . . 375
Drive Systems
All-Wheel Drive . . . . . . . . . . . . . . 199, 293
Driver Assistance Systems . . . . . . . . . 234
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . . . . . . . 132
Driver Mode Control . . . . . . . . . . . . . . . . 204
Driver Mode Control Light . . . . . . . . . 129
Driving Assistance Systems . . . . . . . . . . . . . . . 243
Better Fuel Economy . . . . . . . . . . . . . 172
Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . 262
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Hill and Mountain Roads . . . . . . . . 177
If the Vehicle is Stuck . . . . . . . . . . . . 179
Loss of Control . . . . . . . . . . . . . . . . . . . . 175