engine overheat CADILLAC CT6 2020 User Guide

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
270 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 271
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 271
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 272
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 272
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 272
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 274
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 277
Engine Oil Life System . . . . . . . . . . . 280
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
Engine Air Filter Life System . . . . 281
Engine Air Cleaner/Filter . . . . . . . . . 282
Cooling System . . . . . . . . . . . . . . . . . . . 284
Engine Overheating . . . . . . . . . . . . . . 288
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 289
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
Brake Pad Life System . . . . . . . . . . . 291
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 291 Battery - North America . . . . . . . . . 292
All-Wheel Drive . . . . . . . . . . . . . . . . . . 293
Starter Switch Check . . . . . . . . . . . . . 294
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . 294
Wiper Blade Replacement . . . . . . . 295
Windshield Replacement . . . . . . . . 295
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 296
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 297
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 297
LED Lighting . . . . . . . . . . . . . . . . . . . . . 297
Electrical System
Electrical System Overload . . . . . . 298
Fuses and Circuit Breakers . . . . . . 298
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Instrument Panel Fuse Block . . . . 306
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
All-Season Tires . . . . . . . . . . . . . . . . . . 316
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 316
Low-Profile Tires . . . . . . . . . . . . . . . . . 317
Summer Tires . . . . . . . . . . . . . . . . . . . . 317
Tire Sidewall Labeling . . . . . . . . . . . 317 Tire Designations . . . . . . . . . . . . . . . . . 319
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . . . . . 320
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 322
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 324
Tire Pressure Monitor System . . . 324
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 325
Tire Inspection . . . . . . . . . . . . . . . . . . . 329
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 329
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Buying New Tires . . . . . . . . . . . . . . . . 331
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Uniform Tire Quality Grading . . . 333
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Wheel Replacement . . . . . . . . . . . . . . 335
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 335
If a Tire Goes Flat . . . . . . . . . . . . . . . . 336
Tire Changing . . . . . . . . . . . . . . . . . . . . . 337
Compact Spare Tire . . . . . . . . . . . . . . 342Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . . . . . 343

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
INDEX 403
Driving (cont'd)Off-Road Recovery . . . . . . . . . . . . . . . . 175
Track Events and Competitive . . . 176
Vehicle Load Limits . . . . . . . . . . . . . . 179
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . 176
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
E
Electric Brake Boost . . . . . . . . . . . . . . . . 199
Electric Parking Brake . . . . . . . . . . . . . . 200
Electric Parking Brake Light . . . . . . . 125
Electrical Equipment, Add-On . . . . . 269
Electrical System
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Fuses and Circuit Breakers . . . . . . . 298
Instrument Panel Fuse Block . . . . 306
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Emergency OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . 282
Check Light (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . . . . . 123
Compartment Overview . . . . . . . . . . 274
Coolant Temperature Gauge . . . . . 119 Engine (cont'd)
Coolant Temperature
Warning Light . . . . . . . . . . . . . . . . . . . 129
Cooling System . . . . . . . . . . . . . . . . . . . 284
Drive Belt Routing . . . . . . . . . . . . . . . . 375
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Oil Life System . . . . . . . . . . . . . . . . . . . . 280
Oil Pressure Gauge . . . . . . . . . . . . . . . . 117
Oil Pressure Light . . . . . . . . . . . . . . . . . 130
Overheating . . . . . . . . . . . . . . . . . . . . . . . 288
Power Messages . . . . . . . . . . . . . . . . . . 139
Running While Parked . . . . . . . . . . . 192
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Engine Air Filter Life System . . . . . . 281
Engine Oil Temperature Gauge . . . . . . . . . . . . . . . 118
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . 155
Equipment, Towing . . . . . . . . . . . . . . . . . 267
Event Data Recorders . . . . . . . . . . . . . . 388
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . 155
Extended Parking . . . . . . . . . . . . . . . . . . . 191
Extender, Seat Belt . . . . . . . . . . . . . . . . . . 64
Exterior Lamp Controls . . . . . . . . . . . . 149
Exterior Lamps Off Reminder . . . . . . 151
Exterior Lighting Battery Saver . . . . 156
F
Filter,
Engine Air Cleaner . . . . . . . . . . . . . . . . 282
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . 151
Flashers, Hazard Warning . . . . . . . . . . 152
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 Changing . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Fluid Automatic Transmission . . . . . . . . . 281
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . 33
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Front Seats Heated and Ventilated . . . . . . . . . . . . . 51
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Economy, Driving for Better . . . . . 172
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . . . . . . 261
Filling the Tank . . . . . . . . . . . . . . . . . . . 260
Foreign Countries . . . . . . . . . . . . . . . . . 259

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
406 INDEX
Locks (cont'd)Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Lockout Protection . . . . . . . . . . . . . . . . . 22
Power Door . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Loss of Control . . . . . . . . . . . . . . . . . . . . . . 175
Low Fuel Warning Light . . . . . . . . . . . 130
Low-Profile Tires . . . . . . . . . . . . . . . . . . . . 317
Lower Anchors and Tethers for Children (LATCH System) . . . . . . . . . 84
Lumbar Adjustment . . . . . . . . . . . . . 46, 55 Front Seats . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Maintenance and Care Additional . . . . . . . . . . . . . . . . . . . . . . . . . 365
Maintenance Schedule . . . . . . . . . . . . . 359 Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . . . . . 368
Malfunction Indicator Lamp . . . . . . . 123
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . 197
Massage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Memory Seats . . . . . . . . . . . . . . . . . . . . . . . . 48
Messages Engine Power . . . . . . . . . . . . . . . . . . . . . 139 Messages (cont'd)
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Vehicle Speed . . . . . . . . . . . . . . . . . . . . . 139
Mirror
Rear Camera . . . . . . . . . . . . . . . . . . . . . . . . 35
Mirrors Automatic Dimming . . . . . . . . . . . . . . . . 34
Automatic Dimming Rearview . . . . . 35
Convex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Folding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Heated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Tilt in Reverse . . . . . . . . . . . . . . . . . . . . . . 34
Mirrors, Interior Rearview . . . . . . . . . . . 35
Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Driver Control . . . . . . . . . . . . . . . . . . . . . 204
Monitor System, Tire Pressure . . . . . 324
N
Navigation Connected Services . . . . . . . . . . . . . . . 397
Net, Convenience . . . . . . . . . . . . . . . . . . . 101
New Vehicle Break-In . . . . . . . . . . . . . . . 183
Night Vision System . . . . . . . . . . . . . . . . 250
O
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 Off-Road
Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Oil Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Engine Oil Life System . . . . . . . . . . . 280
Engine Oil Pressure Gauge . . . . . . . 117
Pressure Light . . . . . . . . . . . . . . . . . . . . . 130
Older Children, Restraints . . . . . . . . . . . 77
Online Owner Center . . . . . . . . . . . . . . . 379
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
OnStar Additional Information . . . . 392
OnStar Emergency . . . . . . . . . . . . . . . . . . 391
OnStar Overview . . . . . . . . . . . . . . . . . . . . 390
OnStar Security . . . . . . . . . . . . . . . . . . . . . 391
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Overheating, Engine . . . . . . . . . . . . . . . . 288
Overview Instrument Panel . . . . . . . . . . . . . . . . . . . . 5
P
ParkShifting Out of . . . . . . . . . . . . . . . . . . . . 189
Park Assist . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Parking Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . . 294
Extended . . . . . . . . . . . . . . . . . . . . . . . . . . 191