2019 CADILLAC CT6 engine overheat

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
DRIVING AND OPERATING 283
Passing
More passing distance is needed when
towing a trailer. The combination of
the vehicle and trailer will not
accelerate as quickly and is much
longer than the vehicle alone. It is
necessary to go much farther beyond
the passed vehicle before returning to
the lane. Pass on level roadways.
Avoid passing on hills if possible.
Backing Up
Hold the bottom of the steering wheel
with one hand. To move the trailer to
the left, move that hand to the left. To
move the trailer to the right, move
that hand to the right. Always back up
slowly and, if possible, have someone
guide you.
Making TurnsCaution
Turn more slowly and make wider
arcs when towing a trailer to
prevent damage to your vehicle. (Continued)
Caution (Continued)
Making very sharp turns could
cause the trailer to contact the
vehicle.
Make wider turns than normal when
towing, so trailer will not go over soft
shoulders, over curbs, or strike road
signs, trees, or other objects. Always
signal turns well in advance. Do not
steer or brake suddenly.
Driving on Grades
Reduce speed and shift to a lower gear
before starting down a long or steep
downhill grade. If the transmission is
not shifted down, the brakes may
overheat and result in reduced braking
efficiency.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if the
transmission shifts too often under
heavy loads and/or hilly conditions.
When towing at higher altitudes,
engine coolant will boil at a lower
temperature than at lower altitudes.
If the engine is turned off immediately after towing at high altitude on steep
uphill grades, the vehicle could show
signs similar to engine overheating. To
avoid this, let the engine run,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine off.
If the overheat warning comes on, see
Engine Overheating
0312.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer
on a level surface when possible.
When parking your vehicle and your
trailer on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the
wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
284 DRIVING AND OPERATING
3. When the wheel chocks are inplace, release the regular brakes
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal. .Start the engine.
. Shift into a gear.
. Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more often
when used to tow trailers. See
Maintenance Schedule 0383. It is
especially important to check the
automatic transmission fluid, engine oil, axle lubricant, belts, cooling
system, and brake system before and
during each trip.
Check periodically that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling when Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See
Engine Overheating
0 312.
Trailer Towing
Caution
Towing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer for
important information about
towing a trailer with the vehicle.
Trailer Weight
{Warning
Never exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring the
weight, speed, altitude, road grades,
outside temperature, dimensions of
the front of the trailer, and how
frequently the vehicle is used to tow a
trailer.
{Warning
You and others could be seriously
injured or killed if the trailer is too
heavy or the trailer brakes are
inadequate for the load. The vehicle
may be damaged, and the repairs
would not be covered by the vehicle
warranty.
Only tow a trailer if all the steps in
this section have been followed. Ask
your dealer for advice and
information about towing a trailer.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
2019 - crc - 1/23/19
288 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 289
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 289
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 290
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 290
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 290
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 292
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 299
Engine Oil Life System . . . . . . . . . . . 302
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Engine Air Filter Life System . . . . 304
Engine Air Cleaner/Filter . . . . . . . . . 304
Cooling System . . . . . . . . . . . . . . . . . . . 307
Engine Overheating . . . . . . . . . . . . . . 312
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 313
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Brake Pad Life System . . . . . . . . . . . 315
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 315 Battery - North America . . . . . . . . . 316
All-Wheel Drive . . . . . . . . . . . . . . . . . . 317
Starter Switch Check . . . . . . . . . . . . . 318
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . 318
Wiper Blade Replacement . . . . . . . 319
Windshield Replacement . . . . . . . . 319
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 320
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . . . . . 321
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 321
LED Lighting . . . . . . . . . . . . . . . . . . . . . 321
Electrical System
Electrical System Overload . . . . . . 322
Fuses and Circuit Breakers . . . . . . 322
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Instrument Panel Fuse Block . . . . 330
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
All-Season Tires . . . . . . . . . . . . . . . . . . 340
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 340
Low-Profile Tires . . . . . . . . . . . . . . . . . 340
Summer Tires . . . . . . . . . . . . . . . . . . . . 340
Tire Sidewall Labeling . . . . . . . . . . . 341 Tire Designations . . . . . . . . . . . . . . . . . 343
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . . . . . 344
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 346
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 347
Tire Pressure Monitor System . . . 348
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 349
Tire Inspection . . . . . . . . . . . . . . . . . . . 353
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 353
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Buying New Tires . . . . . . . . . . . . . . . . 355
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Uniform Tire Quality Grading . . . 357
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Wheel Replacement . . . . . . . . . . . . . . 358
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 359
If a Tire Goes Flat . . . . . . . . . . . . . . . . 359
Tire Changing . . . . . . . . . . . . . . . . . . . . . 361
Compact Spare Tire . . . . . . . . . . . . . . 366Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . . . . . 367
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . 370

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) -
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310 VEHICLE CARE
2.0L L4, 3.6L V6, and 4.2L V8 EngineCoolant Surge Tank
The coolant surge tank is in the
engine compartment on the passenger
side of the vehicle. See Engine
Compartment Overview 0292.
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
0 312.
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 0312.
{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
(Continued)
Warning (Continued)
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.
3.0L V6 and 3.6L V6 Engines

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-12533370) -
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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
VEHICLE CARE 313
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 0292 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)