cooling 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
300 VEHICLE CARE
FusesUsage
1 –
2 – Fuses
Usage
3 –
4 – Fuses
Usage
5 Transfer case control/Transmission
control module
ignition
6 –
7 Starter motor
8 Starter pinion
9 Horn
10 –
11 –
12 –
13 High-beam headlamps left/right
18 Right cornering LED
21 Air conditioning clutch
22 Transmission auxiliary oil pump
cooling
23 –
24 Cabin heater pump

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 305
FusesUsage
F1 Electric brake control module–2
F2 –
F3 Headlamp/Daytime running lamps
F4 Right cornering LED
F5 – Fuses
Usage
F6 Front short range radar sensors
F7 Horn
F8 Air conditioning clutch
F9 –
F10 – Fuses
Usage
F11 Automatic headlamp leveling
F12 Starter motor
F13 Starter pinion
F14 –
F15 –
F16 –
F17 Cabin heater pump
F18 Transmission auxiliary oil pump
cooling
F19 Engine control module ignition
F20 Non walk
F21 Ignition coils –even/
Non walk –2
F22 Engine control module ignition –1
F23 Transfer case control module
F24 –
F25 Ignition coils –odd

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 335
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(Continued)
Warning (Continued)
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(Continued)
Warning (Continued)
be unknown. It could fail suddenly
and cause a crash. When replacing
wheels, use a new GM original
equipment wheel.
Tire Chains
Caution
Use tire chains only where legal and
only when necessary. Use low
profile chains that add no more
than 10 mm thickness to the tire
tread and inner sidewall. Use chains
that are the proper size for the tires.
Install them on the tires of the rear
axle. Do not use chains on the tires
of the front axle. Tighten them as
tightly as possible with the ends
securely fastened. Drive slowly and
follow the chain manufacturer's
instructions. If the chains contact
the vehicle, stop and retighten
them. If the contact continues, slow(Continued)

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
SERVICE AND MAINTENANCE 361
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. (1) Check engine oil level
and oil life percentage. Change engine oil and filter,
if needed. Check engine air filter life percentage and
status. Change engine air filter, if needed.
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
Inspect evaporative control system. (3)@ @@
Replace spark plugs. Inspect spark plug wires and/or
boots. (4.2L Engine)@ @
Replace spark plugs. Inspect spark plug wires and/or
boots. (3.6L Engine)@
Change transfer case fluid. (4)@
Change rear axle fluid. (Except V-Series) (4)@
Change rear axle fluid. (V-Series Only) (4)@@@
Change front axle fluid 4WD. (4)@
Drain and fill engine cooling system. (5)@
Visually inspect accessory drive belts. (6)@
Replace brake fluid. (7)
Replace windshield wiper blades. (8)
@ @ @ @ @ @ @ @ @ @
Replace hood and/or body lift support gas struts. (9)@ @
Replace air conditioning desiccant. (10)