
Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
280 Vehicle Care 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.
If the coolant still is not at the
proper level when the system
cools down again, see your
dealer.
CautionIf the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
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 0 128
and Engine Coolant Temperature
Warning Light 0 137 . The vehicle
may also display a message on the
Driver Information Center (DIC).
See Engine Cooling System
Messages 0 149 .
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Service 0 364 .
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
Running the engine without
coolant may cause damage or a
fire. Vehicle damage would not be
covered by the vehicle warranty. If Steam Is Coming from the
Engine Compartment
{ WarningSteam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Just turn it
off and get everyone away from
the vehicle until it cools down.
Wait until there is no sign of
steam or coolant before you open
the hood.
If you keep driving when the
engine is overheated, the liquids
in it can catch fire. You or others
could be badly burned. Stop the
engine if it overheats, and get out
of the vehicle until the engine
is 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

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
Vehicle Care 281too 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 0 265 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-9235592) -
2016 - crc - 11/6/15
Vehicle Care 319CautionThe 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
{ WarningReplacing a wheel with a used
one is dangerous. How it has
been used or how far it has been
driven may be unknown. It could
fail suddenly and cause a crash.
When replacing wheels, use a
new GM original equipment
wheel. Tire Chains
{ WarningIf the vehicle has 265/45R18 size
tires on the rear axle, do not use
tire chains. There is not enough
clearance. Tire chains used on a
vehicle without the proper amount
of clearance can cause damage
to the brakes, suspension,
or other vehicle parts. The area
damaged by the tire chains could
cause loss of control and a crash.
Use another type of traction
device only if its manufacturer
recommends it for the vehicle's
tire size combination and road
conditions. Follow that
manufacturer's instructions. To
avoid vehicle damage, drive slow
and readjust or remove the
traction device if it contacts the
vehicle. Do not spin the wheels. If
traction devices are used, install
them on the rear tires. CautionIf the vehicle is equipped with a
tire size other than 265/45R18,
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 down until it stops. Driving
too fast or spinning the wheels
with chains on will damage the
vehicle.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
346 Service and Maintenance Maintenance Schedule
Additional Required
Services - Normal
12 000 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 miRotate tires, if recommended for the vehicle, and
perform Required Services. Check engine oil level
and oil life percentage. Change engine oil and
filter, if needed. (1)
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @Replace passenger compartment air filter. (2)
@ @ @ @ @ @Inspect evaporative control system. (3)
@ @ @Replace engine air cleaner filter. (4)
@ @ @Replace spark plugs. Inspect spark plug wires.
(2.0L and 3.0L Twin Turbo Engines)
@ @Replace spark plugs. Inspect spark plug wires.
(3.6L Engine Only)
@Drain and fill engine cooling system. (5)
@Change transfer case fluid, if equipped with
AWD. (6)
@Visually inspect accessory drive belts. (7)
@Replace brake fluid. (8)
Footnotes — Maintenance
Schedule Additional Required
Services - Normal
(1) Vehicles with different size front
and rear tires do not have tire
rotation. See Tire Rotation 0 313 . (2) Or every two years, whichever
comes first. More frequent
passenger compartment air filter
replacement may be needed if
driving in areas with heavy traffic,
poor air quality, high dust levels,
or environmental allergens. Passenger compartment air filter
replacement may also be needed if
there is reduced airflow, window
fogging, or odors. Your GM dealer
can help determine when to replace
the filter.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
Service and Maintenance 347(3) Check all fuel and vapor lines
and hoses for proper hook-up,
routing, and condition.
(4) Or every four years, whichever
comes first. If driving in dusty
conditions, inspect the filter at each
oil change or more often as needed.
(5) Or every five years, whichever
comes first. See Cooling
System 0 275 .
(6) Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the transfer case fluid.
Contaminated fluid will decrease the
life of the transfer case and/or axles
and should be replaced.
(7) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(8) Replace brake fluid every five
years. See Brake Fluid 0 283 .

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
348 Service and Maintenance Maintenance Schedule
Additional Required
Services - Severe
12 000 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 miRotate tires, if recommended for the vehicle, and
perform Required Services. Check engine oil level
and oil life percentage. Change engine oil and
filter, if needed. (1)
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @Replace passenger compartment air filter. (2)
@ @ @ @ @ @Inspect evaporative control system. (3)
@ @ @Replace engine air cleaner filter. (4)
@ @ @Replace spark plugs. Inspect spark plug wires.
(2.0L and 3.0L Twin Turbo Engines)
@ @Replace spark plugs. Inspect spark plug wires.
(3.6L Engine Only)
@Change automatic transmission fluid and filter.
@ @ @Change transfer case fluid, if equipped with
AWD. (5)
@ @ @Change rear axle fluid.
@ @ @Change front axle fluid, if equipped with AWD.
@ @ @Drain and fill engine cooling system. (6)
@Visually inspect accessory drive belts. (7)
@Replace brake fluid. (8)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
Service and Maintenance 349Footnotes — Maintenance
Schedule Additional Required
Services - Severe
(1) Vehicles with different size front
and rear tires do not have tire
rotation. See Tire Rotation 0 313 .
(2) Or every two years, whichever
comes first. More frequent
passenger compartment air filter
replacement may be needed if
driving in areas with heavy traffic,
poor air quality, high dust levels,
or environmental allergens.
Passenger compartment air filter
replacement may also be needed if
there is reduced airflow, window
fogging, or odors. Your GM dealer
can help determine when to replace
the filter.
(3) Check all fuel and vapor lines
and hoses for proper hook-up,
routing, and condition.
(4) Or every four years, whichever
comes first. If driving in dusty
conditions, inspect the filter at each
oil change or more often as needed. (5) Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the transfer case fluid.
Contaminated fluid will decrease the
life of the transfer case and/or axles
and should be replaced.
(6) Or every five years, whichever
comes first. See Cooling
System 0 275 .
(7) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(8) Replace brake fluid every five
years. See Brake Fluid 0 283 .Special Application
Services .
Severe Commercial Use
Vehicles Only: Lubricate chassis
components every 5 000 km/
3,000 mi.
.
Have underbody flushing service
performed. See "Underbody
Maintenance" in Exterior
Care 0 333 .

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-9235592) -
2016 - crc - 11/6/15
358 Technical Data
Vehicle Data Capacities and Specifications The following approximate capacities are given in metric and English conversions. See Recommended Fluids and
Lubricants 0 353 for more information.
Application Capacities
Metric English
Air Conditioning Refrigerant For the air conditioning system refrigerant type and
charge amount, see the refrigerant label under the
hood. See your dealer for more information.
Cooling System – Engine
2.0L L4 Engine 8.6 L 9.1 qt
2.0L L4 Engine with Rear A/C 10.3 L 10.9 qt
3.0L V6 Twin Turbo Engine 10.6 L 11.2 qt
3.0L V6 Twin Turbo Engine with Rear A/C 12.3 L 13.0 qt
3.0L V6 Twin Turbo Engine with Rear A/C and Auxiliary
Radiator 13.2 L 13.9 qt
3.6L V6 Engine 9.8 L 10.4 qt
3.6L V6 Engine with Rear A/C 11.4 L 12.0 qt
Cooling System – Twin Turbo
3.0L V6 Engine Intercoolers 3.2 L 3.4 qt