2021 CADILLAC CT5 check engine

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
VEHICLE CARE 317
If the oil is below the cross-hatched
area at the tip of the dipstick and the
engine has been off for at least
15 minutes, add 1 L (1 qt) of the
recommended oil and then recheck
the level. See“Selecting the Right
Engine Oil” later in this section for an
explanation of what kind of oil to use.
For engine oil crankcase capacity, see
Capacities and Specifications 0397.
Caution
Do not add too much oil. Oil levels
above or below the acceptable
operating range shown on the
dipstick are harmful to the engine.
If the oil level is above the
operating range (i.e., the engine has
so much oil that the oil level gets
above the cross-hatched area that
shows the proper operating range),
the engine could be damaged. Drain
the excess oil or limit driving of the
vehicle, and seek a service
professional to remove the
excess oil. See
Engine Compartment Overview
0 313 for the location of the engine oil
fill cap.
Add enough oil to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when through.
Selecting the Right Engine Oil
Selecting the right engine oil depends
on both the proper oil specification
and viscosity grade. See Recommended
Fluids and Lubricants 0392.
Specification
Use full synthetic engine oils that
meet the dexos1 specification. Engine
oils that have been approved by GM
as meeting the dexos1 specification
are marked with the dexos1
approved logo.
Caution
Failure to use the recommended
engine oil or equivalent can result
in engine damage not covered by
the vehicle warranty.
Viscosity Grade
For the 2.0L L4 Turbo (LSY) engine,
use SAE 0W-20 viscosity grade
engine oil.
For the 3.0L V6 Twin Turbo (LGY)
engine, use SAE 5W-30 viscosity grade
engine oil. Cold Temperature
Operation: In an area of extreme cold,
where the temperature falls below
−29 °C (−20 °F), an SAE 0W-30 oil may
be used. An oil of this viscosity grade
will provide easier cold starting for the
engine at extremely low temperatures.
When selecting an oil of the
appropriate viscosity grade, it is
recommended to select an oil of the
correct specification. See
“Specification ”earlier in this section.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
318 VEHICLE CARE
Engine Oil Additives/Engine Oil
Flushes
Do not add anything to the oil. The
recommended oils meeting the dexos1
specification are all that is needed for
good performance and engine
protection.
Engine oil system flushes are not
recommended and could cause engine
damage not covered by the vehicle
warranty.
What to Do with Used Oil
Used engine oil contains certain
elements that can be unhealthy for
your skin and could even cause
cancer. Do not let used oil stay on
your skin for very long. Clean your
skin and nails with soap and water,
or a good hand cleaner. Wash or
properly dispose of clothing or rags
containing used engine oil. See the
manufacturer's warnings about the
use and disposal of oil products.
Used oil can be a threat to the
environment. If you change your own
oil, be sure to drain all the oil from
the filter before disposal. Never
dispose of oil by putting it in the trashor pouring it on the ground, into
sewers, or into streams or bodies of
water. Recycle it by taking it to a place
that collects used oil.
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system
that indicates when to change the
engine oil and filter. This is based on a
combination of factors which include
engine revolutions, engine
temperature, and miles driven. Based
on driving conditions, the mileage at
which an oil change is indicated can
vary considerably. For the oil life
system to work properly, the system
must be reset every time the oil is
changed.
When the system has calculated that
oil life has been diminished, it
indicates that an oil change is
necessary. A CHANGE ENGINE OIL
SOON message comes on. Change the
oil as soon as possible within the next
1 000 km (600 mi). It is possible that,
if driving under the best conditions,
the oil life system might indicate that
an oil change is not necessary for up
to a year. The engine oil and filter
must be changed at least once a year
and at this time the system must be
reset. Your dealer has trained service
people who will perform this work and
reset the system. It is also important
to check the oil regularly over the
course of an oil drain interval and
keep it at the proper level.
If the system is ever reset accidentally,
the oil must be changed at 5 000 km
(3,000 mi) since the last oil change.
Remember to reset the oil life system
whenever the oil is changed.
How to Reset the Engine Oil Life
System
Reset the system whenever the engine
oil is changed so that the system can
calculate the next engine oil change.
To reset the system:
1. Using the DIC buttons, display REMAINING OIL LIFE on the DIC.
See Driver Information Center (DIC)
(Base Level) 0113 or
Driver Information Center (DIC)
(Uplevel) 0116.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
VEHICLE CARE 319
2. Press and hold the thumbwheel onthe steering wheel. When the
confirmation message displays,
select YES. The oil life will change
to 100%.
Be careful not to reset the oil life
display accidentally at any time
other than after the oil is changed.
It cannot be reset accurately until
the next oil change.
The oil life system can also be reset as
follows: 1. Using the DIC buttons, display REMAINING OIL LIFE on the DIC.
See Driver Information Center (DIC)
(Base Level) 0113 or
Driver Information Center (DIC)
(Uplevel) 0116.
2. Fully press and release the accelerator pedal three times
within five seconds.
If the CHANGE ENGINE OIL SOON
message is not on, the system is
reset.
The system is reset when the
CHANGE ENGINE OIL SOON message
is off. If the CHANGE ENGINE OIL SOON
message comes back on when the
vehicle is started, the engine oil life
system has not been reset. Repeat the
procedure.
Automatic Transmission
Fluid
How to Check Automatic
Transmission Fluid
It is not necessary to check the
transmission fluid level.
A transmission fluid leak is the only
reason for fluid loss. If a leak occurs,
take the vehicle to your dealer and
have it repaired as soon as possible.
The vehicle is not equipped with a
transmission fluid level dipstick.
There is a special procedure for
checking and changing the
transmission fluid. Because this
procedure is difficult, this should be
done at the dealer. Contact your dealer
for additional information.
Caution
Use of the incorrect automatic
transmission fluid may damage the
vehicle, and the damage may not be
covered by the vehicle warranty.
Always use the correct automatic
transmission fluid. See
Recommended Fluids and Lubricants
0
392.
Change the fluid and filter at the
intervals listed in Maintenance
Schedule 0383, and be sure to use the
fluid listed in Recommended Fluids and
Lubricants 0392.
Engine Air Filter Life
System
If equipped, this feature provides the
engine air filter’s remaining life and
best timing for a change. The timing
to change an engine air filter depends
on driving and environmental
conditions.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
320 VEHICLE CARE
When to Change the Engine Air
Filter
When the Driver Information Center
(DIC) displays a message to replace
the engine air filter at the next oil
change, follow this timing.
When the DIC displays a message to
replace the engine air filter soon,
replace the engine air filter at the
earliest convenience.
The system must be reset after the
engine air filter is changed.
If the DIC displays a message to check
the engine air filter system, see your
dealer.
How to Reset the Engine Air
Filter Life System
To reset:1. Place the vehicle in P (Park).
2. Display the Air Filter Life on the DIC. See Driver Information Center
(DIC) (Base Level) 0113 or
Driver Information Center (DIC)
(Uplevel) 0116. 3. Press
Ton the steering wheel,
or press the trip odometer reset
stem if the vehicle does not have
DIC controls, to move to the Reset/
Disable display area. Select Reset,
then press the thumbwheel or
press the reset stem for several
seconds.
4. Press the thumbwheel or the reset stem to confirm the reset.
Engine Air Cleaner/Filter
The engine air cleaner/filter is in the
engine compartment on the passenger
side of the vehicle for the 2.0L L4
engine, and in the center of the engine
compartment for the 3.0L V6 engine.
See Engine Compartment Overview
0 313.
When to Inspect the Engine Air
Cleaner/Filter
.For intervals on changing and
inspecting the engine air filter, see
break="2" Maintenance Schedule
0 383.
.If equipped with Engine Air Filter
Life System, see Engine Air Filter Life
System 0319.
.If driving in very dusty areas, follow
the engine air filter inspecting and
changing intervals, see Maintenance
Schedule 0383.
How to Inspect/Replace the
Engine Air Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/filter,
make sure that the engine air cleaner/
filter housing and nearby components
are free of dirt and debris. Do not
clean the engine air cleaner/filter or
components with water or
compressed air.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
VEHICLE CARE 323
{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.
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.
Engine Coolant
The cooling system in the vehicle is
filled with DEX-COOL engine coolant.
SeeMaintenance Schedule 0383 and
Recommended Fluids and Lubricants
0 392. 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
0326.
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.
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.
It is normal to see coolant moving in
the upper coolant hose return line
when the engine is running. It is also
normal to see bubbles entering the
surge tank through the small hose.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
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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.
If coolant is visible but the coolant
level is 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 is cool
before this is done.
If no coolant is visible in the coolant
surge tank, add coolant as follows:
How to Add Coolant to the
Coolant Surge Tank
{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
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
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(Continued)
Warning (Continued)
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.
If no problem is found, check to see if
coolant is visible in the coolant surge
tank. If coolant is visible but the
coolant level is not at or above the
indicated mark, add a 50/50 mixture
of clean, drinkable water and
DEX-COOL coolant at the coolant
surge tank, but be sure the cooling
system, including the coolant surge
tank pressure cap, is cool before you
do it.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
VEHICLE CARE 325
2.0L L4 Engine
Automatic Coolant Service Fill
Instructions
The vehicle is equipped with a service
feature that assists with filling and
removing air from the cooling system
after service of components or when
coolant is added after being too low.
To use the service feature:
1. With a cold system, add coolant tothe indicated line on the
surge tank.
2. Replace the pressure cap on the surge tank. To activate the service feature:
1. Connect the vehicle to a battery charger.
2. Turn the ignition on. See Ignition
Positions 0224.
3. Turn off the air conditioning.
4. Set the parking brake.
5. At the same time, press the accelerator and the brake pedal for
two seconds, then release.
6. At the end of the cycle, check the coolant level in the surge tank and
add coolant if it is below the
indicated line. Turn the ignition
off, allow the Electronic Control
Module (ECM) to go to sleep, about
two minutes, and repeat Steps 2–6.
Listen for pump activation and
movement of the control valves while
watching the level of the coolant in
the surge tank. If the tank empties,
turn the ignition off, carefully remove
the pressure cap, refill to the indicated
line, replace the pressure cap, and
repeat Steps 2–6.
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.
3.0L V6 Engine
1. Remove the coolant surge tank pressure 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. 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.

Cadillac CT5 Owner Manual (GMNA-Localizing-U.S./Canada-14584312) -
2021 - CRC - 11/23/20
326 VEHICLE CARE
3. Fill the surge tank with the propermixture 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
surge tank until the level reaches
the indicated level mark.
5. Replace the pressure cap tightly. 6. Check the level in the surge tank
after the engine is shut off and the
cooling system has cooled down.
If the coolant is not at the proper
level, repeat Steps 1–6. 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.
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 0405.
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.