2018 CADILLAC XTS cooling

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
246 VEHICLE CARE
3.6L V6 Twin Turbo Engine
1. Electric Engine Cooling Fans(Out of View)
2. Charged Air Coolant (CAC) Bottle and Pressure Cap
3. Coolant Surge Tank and Pressure 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 engine and Charged Air Coolant
(CAC) cooling systems in the vehicle
are filled with DEX-COOL engine
coolant mixture.
See Recommended Fluids and
Lubricants 0326 and Maintenance
Schedule 0317.
The following explains the cooling
systems and how to check and add
coolant when it is low. If there is a
problem with engine overheating, see
Engine Overheating 0249.
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. 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 XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
VEHICLE CARE 247
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 pouring 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.
The engine coolant surge tank and
CAC bottle are in the engine
compartment on the driver side of the
vehicle. See Engine Compartment
Overview 0236.
Check to see if coolant is visible in the
surge tank and CAC bottle. If the
coolant inside the surge tank is
boiling, do not do anything else until
it cools down. If coolant is visible but
the coolant level is not at or above the
mark pointed to on the surge tank or
at the CAC bottle cold fill mark, add a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant.
Be sure the cooling system is cool
before this is done. If no coolant is visible in the coolant
surge tank or CAC bottle, add coolant
as follows:
How to Add Coolant to the
Surge Tank
{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.
{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.

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
248 VEHICLE CARE
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.
The coolant surge tank pressure cap
can be removed when the cooling
system, including the surge tank
pressure cap and upper radiator hose,
is no longer hot.
1. Turn the pressure cap slowly counterclockwise. If a hiss is
heard, wait for that to stop.
A hiss means there is still some
pressure left.
2. Keep turning the pressure cap slowly and remove it. 3. Fill the coolant surge tank with
the proper mixture to the mark
pointed to on the front of the
coolant surge tank.
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 fans. 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 mark pointed to on the front
of the coolant surge tank.
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 1–5.
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.
How to Add Coolant to the CAC
Bottle
{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.
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.

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
VEHICLE CARE 249
The CAC bottle pressure cap can be
removed when the Charged Air
Coolant cooling system, including the
CAC bottle pressure cap, is no
longer hot.
1. Turn the pressure cap slowlycounterclockwise and remove it.
2. Fill the CAC bottle with the proper mixture to the cold fill
mark pointed to on the front of
the CAC bottle.
3. Replace the pressure cap tightly.
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 engine coolant
temperature gauge and an engine
temperature light to warn of engine
overheating.
There are also engine hot messages
that may display in the Driver
Information Center (DIC).
If the decision is made not to lift the
hood when one of these warnings
appears, but get service help right
away. See Roadside Service 0338.
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 fans are running. If the engine
is overheating, the fans should be
running. If they are 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 XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
250 VEHICLE CARE
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.
. Tows a trailer.
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 temperature overheat gauge is
no longer in the overheat zone or an
overheat warning no longer displays,
the vehicle can be driven. Continue to drive the vehicle slow for about
10 minutes. Keep a safe vehicle
distance from the car in front of you.
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.
Also, see
“Overheated Engine
Protection Operating Mode ”next in
this section.
Overheated Engine
Protection Operating Mode
This emergency operating mode
allows the vehicle to be driven to a
safe place in an emergency situation.
If an overheated engine condition
exists, an overheat protection mode,
which alternates firing groups of
cylinders, helps prevent engine damage. In this mode, there is
significant loss in power and engine
performance.
The engine coolant temperature
warning light comes on in the
instrument cluster, to indicate the
vehicle has entered overheated engine
protection operating mode. The
temperature gauge also indicates an
overheat condition exists. Driving
extended distances and/or towing a
trailer in the overheat protection
mode should be avoided.
Power Steering Fluid (LFX
with FWD)
The vehicle has electric power steering
and does not use power steering fluid.
Power Steering Fluid
(LF3 and LFX with AWD)

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
262 VEHICLE CARE
FusesUsage
23 Variable effort steering module
24 Front power windows
25 Retained accessory power
26 ABS pump
27 Electric park brake
28 Rear window defogger
29 Passive entry/Passive start
30 Spare
31 Heated driver seat
32 Stop lamps —center
high mounted stop
lamp/Backup-reverse
lamps/Interior
33 Heated passenger seat
34 ABS valves
35 Amplifier
36 Tail park lamp —
driver side Fuses
Usage
37 Right high-beam headlamp
38 Left high-beam headlamp
39 Tail park lamp —
passenger side
40 Long range radar
41 Brake vacuum assist pump
42 Cooling fan high speed
43 –
44 –
45 Cooling fan low speed
46 Cooling fan control
47 Pre-catalytic converter O2 sensor
heater/Canister purge
solenoid
48 Low temperature radiator coolant pump
49 Right headlamp LED Fuses
Usage
50 Left headlamp LED
51 Horn
52 Display/Ignition
53 Air quality sensor/ Inside rearview
mirror/Rear vision
camera
54 HVAC/Reflective LED alert display
55 Driver and passenger door switches/Outside
rearview mirror
switch/Mirror
memory module
56 Windshield washer
57 –
58 –
59 –
60 Heated outside rearview mirror
61 –
62 Front seats massage module

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
VEHICLE CARE 263
FusesUsage
63 –
64 Spare
65 Spare
66 Trunk release
67 Chassis control module
68 –
69 Battery voltage sensor
70 Canister vent solenoid
71 Memory seat module
72 Electric power steering
Relays Usage
1 A/C clutch
2 Starter
3 –
4 Wiper speed
5 Wiper control
6 –
7 Powertrain Relays
Usage
8 –
9 Cooling fan —high
speed
10 Cooling fan —low
speed
11 Tail/Park lamps
12 –
13 Cooling fan control
14 Low beam LED headlamps
15 Run/Crank
16 –
17 Rear window and mirror defoggerInstrument Panel Fuse
Block
The instrument panel fuse block is in
the instrument panel, on the driver
side of the vehicle. To access the
fuses, open the fuse panel door by
pulling down at the top.
Press in on the sides of the door to
release it from the instrument panel.
Pull the door toward you to release it
from the hinge.

Cadillac XTS Owner Manual (GMNA-Localizing-U.S./Canada-11354412) -
2018 - crc - 11/16/17
286 VEHICLE CARE
{Warning
Using the wrong replacement
wheels, wheel bolts, or wheel nuts
can be dangerous. It could affect
the braking and handling of the
vehicle. Tires can lose air, and
cause loss of control, causing a
crash. Always use the correct wheel,
wheel bolts, and wheel nuts for
replacement.
Caution
The 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.
Professional vehicle wheels have a
unique offset and bolt hole diameter.
Professional vehicle wheels have six wheel nuts. Non-professional vehicle
wheels have five wheel nuts. See
Tire
Changing 0295.
Used Replacement Wheels
{Warning
Replacing 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
{Warning
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,
(Continued)
Warning (Continued)
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 front tires.
If a Tire Goes Flat
It is unusual for a tire to blow out
while driving, especially if the tires are
maintained properly. See Tires0267.
If air goes out of a tire, it is much
more likely to leak out slowly. But if
there is ever a blowout, here are a few
tips about what to expect and what
to do: