cooling CADILLAC CT6 2020 Owner's Manual

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
156 LIGHTING
Battery Load Management
The vehicle has Electric Power
Management (EPM) that estimates the
battery's temperature and state of
charge. It then adjusts the voltage for
best performance and extended life of
the battery.
When the battery's state of charge is
low, the voltage is raised slightly to
quickly bring the charge back up.
When the state of charge is high, the
voltage is lowered slightly to prevent
overcharging. If the vehicle has a
voltmeter gauge or a voltage display
on the Driver Information Center
(DIC), you may see the voltage move
up or down. This is normal. If there is
a problem, an alert will be displayed.
The battery can be discharged at idle
if the electrical loads are very high.
This is true for all vehicles. This is
because the generator (alternator)
may not be spinning fast enough at
idle to produce all of the power
needed for very high electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, rearwindow defogger, climate control fan
at high speed, heated seats, engine
cooling fans, trailer loads, and loads
plugged into accessory power outlets.
EPM works to prevent excessive
discharge of the battery. It does this
by balancing the generator's output
and the vehicle's electrical needs.
It can increase engine idle speed to
generate more power whenever
needed. It can temporarily reduce the
power demands of some accessories.
Normally, these actions occur in steps
or levels, without being noticeable. In
rare cases at the highest levels of
corrective action, this action may be
noticeable to the driver. If so, a DIC
message might be displayed and it is
recommended that the driver reduce
the electrical loads as much as
possible.
Battery Power Protection
The battery saver feature is designed
to protect the vehicle's battery.
If some interior lamps are left on and
the ignition is turned off, the battery
rundown protection system
automatically turns the lamp off after
some time.
Exterior Lighting Battery
Saver
The exterior lamps turn off about
10 minutes after the ignition is turned
off, if the parking lamps or headlamps
have been manually left on. This
protects against draining the battery.
To restart the 10-minute timer, turn
the exterior lamp control to the off
position and then back to the parking
lamp or headlamp position.
To keep the lamps on for more than
10 minutes, the ignition must be on or
in ACC/ACCESSORY.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
158 CLIMATE CONTROLS
Climate Controls
Climate Control Systems
Automatic Climate ControlSystem (Dual Zone) . . . . . . . . . . . . 158
Automatic Climate Control System (Quad Zone) . . . . . . . . . . . . 163
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Climate Control Systems
Automatic Climate Control System (Dual Zone)
The climate control buttons on the center stack and on the climate control
display are used to adjust the heating, cooling, and ventilation.
Center Stack Climate Controls
1. Driver and Passenger Temperature Controls
2. Fan Control
3. Driver and Passenger Heated and Ventilated Seats (If Equipped)
4. Rear Window Defogger 5. Defrost
6. OFF (Fan)
7. Recirculation
8. AUTO (Automatic Operation)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
CLIMATE CONTROLS 163
Automatic Climate Control System (Quad Zone)
The climate control buttons on the center stack and on the climate control
display are used to adjust the heating, cooling, and ventilation.
Center Stack Climate Controls
1. Driver and Passenger Temperature Controls
2. Fan Control
3. Driver and Passenger Heated and Ventilated Seats (If Equipped)
4. Rear Window Defogger 5. Defrost
6. OFF (Fan)
7. Recirculation
8. AUTO (Automatic Operation)
Climate Control Display
1. Driver and Passenger
Temperature Display
2. Fan Control
3. Driver and Passenger Temperature Controls
4. Sync (Synchronized Temperature)
5. Recirculation
6. Driver and Passenger Air Delivery Mode Controls
7. Auto (Automatic Operation)
8. A/C (Air Conditioning)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 177
Hydroplaning
Hydroplaning is dangerous. Water can
build up under the vehicle's tires so
they actually ride on the water. This
can happen if the road is wet enough
and you are going fast enough. When
the vehicle is hydroplaning, it has
little or no contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
. Pass with caution.
. Keep windshield wiping equipment
in good shape.
. Keep the windshield washer fluid
reservoir filled.
. Have good tires with proper tread
depth. See Tires0315.
. Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving on
flat or rolling terrain. Tips include:
.Keep the vehicle serviced and in
good shape.
. Check all fluid levels and brakes,
tires, cooling system, and
transmission.
. Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the vehicle
on a long downhill slope can cause
brake overheating, can reduce brake
performance, and could result in a
loss of braking. Shift the
transmission to a lower gear to let
the engine assist the brakes on a
steep downhill slope.
{Warning
Coasting downhill in N (Neutral) or
with the ignition off is dangerous.
This can cause overheating of the
brakes and loss of steering assist.
Always have the engine running
and the vehicle in gear.
. Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the
center line.
. Be alert on top of hills; something
could be in your lane (e.g., stalled
car, crash).
. Pay attention to special road signs
(e.g., falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 265
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 Overheating0288.
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.
3. When the wheel chocks are in place, 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 0359. 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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
266 DRIVING AND OPERATING
Engine Cooling when Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. SeeEngine Overheating
0 288.
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.
Gross Vehicle Weight
Rating (GVWR)
For information about the vehicle's
maximum load capacity, see
Vehicle
Load Limits 0179. When calculating
the GVWR with a trailer attached, the trailer tongue weight must be
included as part of the weight the
vehicle is carrying.
Maximum Trailer Weight
The trailer should never weigh more
than 408 kg (900 lb) for Platinum
vehicles with the 4.2L V8 engine, or
454 kg (1,000 lb) for all other models.
The maximum allowable weight of the
trailer may be lower based on the
weight of the passengers and cargo in
your trailer.
Trailer Load Balance
The correct trailer load balance must
be maintained to ensure trailer
stability. Incorrect load balance is a
leading cause of trailer sway.

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 275
1. Engine Coolant Surge Tank andPressure Cap. See Cooling System
0 284.
2. Engine Air Cleaner/Filter 0282.
3. Engine Cooling Fan (Out of View). See Cooling System 0284.
4. Engine Oil Fill Cap. See Engine Oil
0 277.
5. Engine Oil Dipstick. See Engine
Oil 0277.
6. Remote Positive (+) Battery Terminal. See Jump Starting -
North America 0343.
7. Engine Compartment Fuse Block
0299.
8. Brake Fluid Reservoir. See Brake
Fluid 0291.
9. Windshield Washer Fluid Reservoir. See Washer Fluid
0 289.
10. Remote Negative (-) Battery Terminal. See Jump Starting -
North America 0343.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 277
1. Passenger Side EngineCompartment Fuse Block. See
Engine Compartment Fuse Block
0299.
2. Engine Coolant Surge Tank and Pressure Cap. See Cooling System
0 284.
3. Passenger Side Engine Air Cleaner/Filter. See Engine Air
Cleaner/Filter 0282.
4. Engine Oil Fill Cap. See Engine Oil
0 277.
5. Engine Oil Dipstick. See Engine
Oil 0277.
6. Engine Cooling Fan (Out of View). See Cooling System 0284.
7. Driver Side Engine Air Cleaner/ Filter. See Engine Air Cleaner/
Filter 0282.
8. Remote Positive (+) Battery Terminal. See Jump Starting -
North America 0343.
9. Brake Fluid Reservoir. See Brake
Fluid 0291. 10. Windshield Washer Fluid
Reservoir. See Washer Fluid
0 289.
11. Driver Side Engine Compartment Fuse Block. See Engine
Compartment Fuse Block 0299.
12. Remote Negative (-) Battery Terminal. See Jump Starting -
North America 0343.
Engine Oil
To ensure proper engine performance
and long life, careful attention must
be paid to engine oil. Following these
simple, but important steps will help
protect your investment:
.
Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
“Selecting the Right Engine Oil” in
this section.
. Check the engine oil level regularly
and maintain the proper oil level.
See “Checking Engine Oil” and
“When to Add Engine Oil” later in
this section. .
Change the engine oil at the
appropriate time. See Engine Oil
Life System 0280.
. Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.
Checking Engine Oil
Check the engine oil level regularly,
every 650 km (400 mi), especially prior
to a long trip. The engine oil dipstick
handle is a loop. See Engine
Compartment Overview 0274 for the
location.
{Warning
The engine oil dipstick handle may
be hot; it could burn you. Use a
towel or glove to touch the dipstick
handle.
If a low oil Driver Information Center
(DIC) message displays, check the oil
level.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
284 VEHICLE CARE
4.2L V8 Engine (Passenger Side)
1. Screws (4)
2. Bolts (3)
3. Diagonal Brace
1. Remove the three bolts (2) andthe diagonal brace (3).
2. Remove the four screws (1) on top of the engine air cleaner/
filter cover.
3. Lift the engine air cleaner/filter cover open on the hinge.
4. Lift and remove the engine air cleaner/filter.
5. Inspect or replace the engine air cleaner/filter. 6. Reverse Steps 1–4 to reinstall the
engine air cleaner/filter cover
and diagonal brace.
7. If equipped, reset the engine air filter life system after replacing
the engine air filter. See Engine
Air Filter Life System 0281.
{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. Use caution
when working on the engine. Do
not start the engine or drive the
vehicle with the air cleaner/filter
off, as flames may be present if the
engine backfires.
Caution
If the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always have
the air cleaner/filter in place when
driving.
Cooling System
The cooling system allows the engine
to maintain the correct working
temperature.
3.6L V6 Engine
1. Engine Coolant Surge Tank
and Pressure Cap (Under
Cover)
2. Engine Cooling Fan (Out of View)