2021 CADILLAC CT4 heating

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
318 VEHICLE CARE
2.7L L4 Engine
1. Engine Coolant Surge Tank andPressure Cap
2. Engine Cooling Fan (Out of View)
3. Cooling System Air Bleeder Cap
{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
leak; all coolant could leak out.
That could cause an engine fire and
can burn you. Fix any leak before
driving the vehicle.
Engine Coolant
The cooling system in the vehicle is
filled with DEX-COOL engine coolant.
See Maintenance Schedule 0380 and
Recommended Fluids and Lubricants
0 391.
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 0322.
What to Use
{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.
Use a 50/50 mixture of clean
drinkable water and DEX-COOL
coolant. 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.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
322 VEHICLE CARE
the pressure cap, refill to the indicated
line, replace the pressure cap, and
repeat steps 6.2–6.6.
The fill and air removal process will
run for approximately 15 minutes.
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.
Engine Overheating
The vehicle has an indicator to warn
of the engine overheating.
If the decision is made not to lift the
hood when this warning appears, get
service help right away. See Roadside
Service 0403.
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 overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 331
When the electrical load is too heavy
a circuit breaker opens, protecting the
circuit until overcurrent condition is
removed. This greatly reduces the
chance of circuit overload and fire
caused by electrical problems.
Fuses and circuit breakers protect
electrical devices in the vehicle.
Replace a blown or open fuse with a
new one of the identical size and
rating.
If there is a problem on the road and
a fuse needs to be replaced, the
same amperage fuse can be borrowed.
Choose some feature of the vehicle
that is not needed to use and replace
it as soon as possible.
Headlamp Wiring
An electrical overload may cause the
lamps to go on and off, or in some
cases to remain off. Have the
headlamp wiring checked right away if
the lamps go on and off or remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop. Wiper function is
available immediately after the wiper
switch is set to off, and back to on.
To protect the wiper motor from
overheating, the wipers may slow
down when the windshield is dry for a
long period of time. If a period of dry
operation, or little moisture, exceeds
10 minutes, the wipers may switch to
intermittent operation, and remain
there. When moisture is again
detected on the windshield, wiper
operation will return to the operator
selected speed.
Although the circuit is protected from
electrical overload, overload due to
heavy snow or ice may cause wiper
linkage damage. Always clear ice and
heavy snow from the windshield
before using the windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit
breakers. This greatly reduces the
chance of damage caused by electrical
problems.
{Danger
Fuses and circuit breakers are
marked with their ampere rating.
Do not exceed the
specified amperage rating when
replacing fuses and circuit breakers.
Use of an oversized fuse or circuit
breaker can result in a vehicle fire.
You and others could be seriously
injured or killed.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 339
Wheels and Tires
Tires
Every new GM vehicle has
high-quality tires made by a
leading tire manufacturer. See the
warranty manual for information
regarding the tire warranty and
where to get service. For
additional information refer to the
tire manufacturer.
{Warning
.Poorly maintained and
improperly used tires are
dangerous.
.Overloading the tires can
cause overheating as a result
of too much flexing. There
could be a blowout and a
serious crash. SeeVehicle
Load Limits 0214.
.Underinflated tires pose the
same danger as overloaded
tires. The resulting crash
(Continued)
Warning (Continued)
could cause serious injury.
Check all tires frequently to
maintain the recommended
pressure. Tire pressure should
be checked when the tires
are cold.
.Overinflated tires are more
likely to be cut, punctured,
or broken by a sudden impact
— such as when hitting a
pothole. Keep tires at the
recommended pressure.
.Worn or old tires can cause a
crash. If the tread is badly
worn, replace them.
.Replace any tires that have
been damaged by impacts
with potholes, curbs, etc.
.Improperly repaired tires can
cause a crash. Only the dealer
or an authorized tire service
(Continued)
Warning (Continued)
center should repair, replace,
dismount, and mount the
tires.
.Do not spin the tires in
excess of 56 km/h (35 mph)
on slippery surfaces such as
snow, mud, ice, etc. Excessive
spinning may cause the tires
to explode.
See Tire Pressure for High-Speed
Operation 0347 for inflation
pressure adjustment for
high-speed driving.
All-Season Tires
This vehicle may come with all-season
tires. These tires are designed to
provide good overall performance on
most road surfaces and weather
conditions. Original equipment tires
designed to GM's specific tire
performance criteria have a TPC
specification code molded onto the
sidewall. Original equipment

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
346 VEHICLE CARE
treadwear. Ratings are determined
by tire manufacturers using
government testing procedures.
The ratings are molded into the
sidewall of the tire. SeeUniform
Tire Quality Grading 0356.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated cargo
load. See Vehicle Load Limits 0214.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a vehicle
showing the vehicle capacity
weight and the original equipment
tire size and recommended
inflation pressure. See “Tire and
Loading Information Label” under
Vehicle Load Limits 0214.
Tire Pressure
Tires need the correct amount of
air pressure to operate effectively.
{Warning
Neither tire underinflation nor
overinflation is good.
Underinflated tires, or tires that
do not have enough air, can
result in:
.Tire overloading and
overheating, which could lead
to a blowout.
.Premature or irregular wear.
.Poor handling.
.Reduced fuel economy.
Overinflated tires, or tires that
have too much air, can result in:
.Unusual wear.
.Poor handling.
.Rough ride.
.Needless damage from road
hazards. The Tire and Loading Information
label on the vehicle indicates the
original equipment tires and the
correct cold tire inflation
pressures. The recommended
pressure is the minimum air
pressure needed to support the
vehicle's maximum load carrying
capacity. See
Vehicle Load Limits
0 214.
How the vehicle is loaded affects
vehicle handling and ride comfort.
Never load the vehicle with more
weight than it was designed to
carry.
When to Check
Check the pressure of the tires
once a month or more.
How to Check
Use a good quality pocket-type
gauge to check tire pressure.
Proper tire inflation cannot be
determined by looking at the tire.
Check the tire inflation pressure
when the tires are cold, meaning

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
424 INDEX
Distracted Driving . . . . . . . . . . . . . . . . . . 203
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . 130
DoorAjar Light . . . . . . . . . . . . . . . . . . . . . . . . . 107
Delayed Locking . . . . . . . . . . . . . . . . . . . 17
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . 17
Drive Belt Routing, Engine . . . . . . . . . 398
Drive Systems All-Wheel Drive . . . . . . . . . . . . . 236, 327
Driver
Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Driver Assistance Systems . . . . . . . . . 275
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . .107, 110
Driver Mode Control . . . . . . . . . . . . . . . . 241
Driver Mode Control Light . . . . . . . . . 103
Driving
Assistance Systems . . . . . . . . . . . . . . . 283
Better Fuel Economy . . . . . . . . . . . . . 203
Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . 297
Competitive . . . . . . . . . . . . . . . . . . . . . . . 246
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Hill and Mountain Roads . . . . . . . . 212
If the Vehicle is Stuck . . . . . . . . . . . . 214
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Loss of Control . . . . . . . . . . . . . . . . . . . . 206 Driving (cont'd)
Off-Road Recovery . . . . . . . . . . . . . . . . 206
Track Events and
Competitive . . . . . . . . . . . . . . . . . . . . . . 207
Vehicle Load Limits . . . . . . . . . . . . . . 214
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . 211
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . . . . . 196
E
Electric Brake Boost . . . . . . . . . . . . . . . . 236
Electric Parking Brake . . . . . . . . . . . . . . 237
Electric Parking Brake Light . . . . . . . 100
Electrical Equipment, Add-On . . . . . 303
Electrical SystemEngine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Fuses and Circuit Breakers . . . . . . . 331
Instrument Panel Fuse Block . . . . 334
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Emergency OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
Engine
Air Cleaner/Filter . . . . . . . . . . . . . . . . . 316 Engine (cont'd)
Check Light (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . . . . . . 97
Compartment Overview . . . . . . . . . . 309
Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . . . . 94, 95
Coolant Temperature
Warning Light . . . . . . . . . . . . . . . . . . . 103
Cooling System . . . . . . . . . . . . . . . . . . . 317
Drive Belt Routing . . . . . . . . . . . . . . . . 398
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Oil Life System . . . . . . . . . . . . . . . . . . . . 314
Oil Pressure Light . . . . . . . . . . . . . . . . . 104
Overheating . . . . . . . . . . . . . . . . . . . . . . . 322
Power Messages . . . . . . . . . . . . . . . . . . 117
Running While Parked . . . . . . . . . . . 227
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Engine Air Filter Life System . . . . . . 315
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . 131
Equipment, Towing . . . . . . . . . . . . . . . . . 302
Event Data Recorders . . . . . . . . . . . . . . 411
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . 132
Extended Parking . . . . . . . . . . . . . . . . . . . 226
Extender, Seat Belt . . . . . . . . . . . . . . . . . . 46
Exterior Lamp Controls . . . . . . . . . . . . 126
Exterior Lamps Off Reminder . . . . . . 128
Exterior Lighting Battery Saver . . . . 133

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
426 INDEX
Headlamps (cont'd)High/Low Beam Changer . . . . . . . . . 128
Lamps On Reminder . . . . . . . . . . . . . . 106
Heated Steering Wheel . . . . . . . . . . . . . . . . . . . . . 82
Heated and Ventilated Front Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . 25
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
High-Beam On Light . . . . . . . . . . . . . . . . 105
High-Speed Operation . . . . . . . . . . . . . . 347
Hill and Mountain Roads . . . . . . . . . . 212
Hill Start Assist (HSA) . . . . . . . . . . . . . 238
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
How to Wear Seat Belts Properly . . . 42
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
I
If the System Needs Service . . . . . . . 163
Ignition Positions . . . . . . . . . . . . . . . . . . . 219
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Indicator Pedestrian Ahead . . . . . . . . . . . . . . . . . 102
Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . 102 Infants and Young Children,
Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Information Publication Ordering . . . . . . . . . . . . . 408
Infotainment System . . . . . . . . . . . . . . . 412
Instrument Cluster . . . . . . . . . . . . . . 88, 90
Instrument Panel Overview . . . . . . . . . . . 4
Interior Rearview Mirrors . . . . . . . . . . . 26
Introduction . . . . . . . . . . . . . . . . . . . . . . 1, 134
J
Jump Starting - North America . . . . 366
K
Keyless Entry Remote (RKE) System . . . . . . . . . . . . . . . 7
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
L
Labeling, Tire Sidewall . . . . . . . . . . . . . 342
Lamps
Cornering . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Courtesy . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Daytime Running (DRL) . . . . . . . . . . 128
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Exterior Controls . . . . . . . . . . . . . . . . . . 126
Exterior Lamps Off Reminder . . . . 128
Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Lamps (cont'd)
Front Turn Signal . . . . . . . . . . . . . . . . . 330
Malfunction Indicator (Check
Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
On Reminder . . . . . . . . . . . . . . . . . . . . . . 106
Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Lane Change Alert (LCA) . . . . . . . . . . . 289
Lane Keep Assist (LKA) . . . . . . . . . . . . 291
Lane Keep Assist Light . . . . . . . . . . . . . 101
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . 44
LATCH System Replacing Parts after a Crash . . . . . 72
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . . . . 65
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . 330
Light Performance Shifting . . . . . . . . . . . . . 101
Lighting Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Illumination Control . . . . . . . . . . . . . . 130
LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Lights Airbag Readiness . . . . . . . . . . . . . . . . . . 96
Antilock Brake System (ABS)Warning . . . . . . . . . . . . . . . . . . . . . . . . . 100
Automatic Vehicle Hold . . . . . . . . . . 101
Brake System Warning . . . . . . . . . . . . 99

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
428 INDEX
N
NavigationConnected Services . . . . . . . . . . . . . . . 418
Destination . . . . . . . . . . . . . . . . . . . . . . . . 155
Using the System . . . . . . . . . . . . . . . . . 150
Navigation Symbols . . . . . . . . . . . . . . . . 154
New Vehicle Break-In . . . . . . . . . . . . . . . 218
O
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Oil Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Engine Oil Life System . . . . . . . . . . . 314
Pressure Light . . . . . . . . . . . . . . . . . . . . . 104
Older Children, Restraints . . . . . . . . . . . 59
Online Owner Center . . . . . . . . . . . . . . . 402
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
OnStar Additional Information . . . . 414
OnStar Emergency . . . . . . . . . . . . . . . . . . 414
OnStar Overview . . . . . . . . . . . . . . . . . . . . 413
OnStar Security . . . . . . . . . . . . . . . . . . . . . 414
OnStar System . . . . . . . . . . . . . . . . .149, 160
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Overheating, Engine . . . . . . . . . . . . . . . . 322
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Instrument Panel . . . . . . . . . . . . . . . . . . . . 4
P
ParkShifting Into . . . . . . . . . . . . . . . . 223, 224
Shifting Out of . . . . . . . . . . . . . . . . . . . . 225
Park Assist . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Parking Brake and P (Park)Mechanism Check . . . . . . . . . . . . . . . 327
Extended . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Over Things That Burn . . . . . . . . . . . 226
Parking or Backing Assistance Systems . . . . . . . . . . . . . . . 277
Passenger Airbag Status
Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Passenger Compartment Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Passenger Sensing System . . . . . . . . . . 53
Pedestrian Ahead Indicator . . . . . . . . 102
Perchlorate Materials
Requirements, California . . . . . . . . . 306
Performance Shifting Light . . . . . . . . 101
Personalization Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Phone
Apple CarPlay and
Android Auto . . . . . . . . . . . . . . . . . . . . 174
Bluetooth . . . . . . . . . . . . . . . . . . . . 169, 170
Port USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Positioning
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Power Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . 17
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Protection, Battery . . . . . . . . . . . . . . . . 133
Retained Accessory (RAP) . . . . . . . . 223
Seat Adjustment . . . . . . . . . . . . . . . . . . . 32
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Pregnancy, Using Seat Belts . . . . . . . . . 46
Privacy Vehicle Data Recording . . . . . . . . . . 410
Problems with Route Guidance . . . . 162
Program Courtesy Transportation . . . . . . . . . 405
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . 294
Proposition 65 Warning,
California . . . . . . . . . . . . . . .305, 326, 366,
Back Cover