2023 HYUNDAI SONATA coolant level

While Driving
6-152
Driving in Flooded Areas
Avoid driving through flooded areas
unless you are sure the water is no
higher than the bottom of the wheel hub.
Drive through any water slowly. Allow
adequate stopping distance because
brake performance may be reduced.
After driving through water, dry the
brakes by gently applying them several
times while the vehicle is moving slowly.
Highway Driving
Tires
Adjust the tire inflation, as specified.
Under-inflation may overheat or damage
the tires.
Do not install worn-out or damaged tires,
which may reduce traction or adversely
affect vehicle handling. This could lead
to sudden tire failure that may cause
loss of vehicle control resulting in an
accident.
Information
Never over-inflate your tires above the
maximum inflation pressure, as specified
on your tires.
Fuel, engine coolant and engine oil
Driving at higher speeds on the highway
consumes more fuel and is less efficient
than driving at a slower, more moderate
speed. Maintain a moderate speed in
order to conserve fuel when driving on
the highway.
Be sure to check both the engine coolant
level and the engine oil before driving.
Drive belt
A loose or damaged drive belt may
overheat the engine.

While Driving
6-154
Winter Precautions
Use high quality ethylene glycol
coolant
Your vehicle is delivered with high
quality ethylene glycol coolant in the
cooling system. It is the only type of
coolant that should be used because it
helps prevent corrosion in the cooling
system, lubricates the water pump and
prevents freezing. Be sure to replace or
replenish your coolant in accordance
with the maintenance schedule in
chapter 8. Before winter, have your
coolant tested to assure that its freezing
point is sufficient for the temperatures
anticipated during the winter.
Change to "winter weight" oil if necessary
In some climates it is recommended that
a lower viscosity "winter weight" oil be
used during cold weather. See chapter 8
for recommendations. If you aren't sure
what weight oil you should use, consult
an authorized HYUNDAI dealer.
Check battery and cables
Winter puts additional burdens on the
battery system. Visually inspect the
battery and cables as described in
chapter 8. The level of charge in your
battery can be checked by an authorized
HYUNDAI dealer or a service station.Check spark plugs and ignition
system
Inspect your spark plugs as described in
chapter 8 and replace them if necessary. Also check all ignition wiring and
components to be sure they are not
cracked, worn or damaged in any way.
Use approved window washer anti-
freeze in system
To keep the water in the window washer
system from freezing, add an approved
window washer anti-freeze solution in
accordance with instructions on the
container. Window washer anti-freeze is
available from an authorized HYUNDAI
dealer and most auto parts outlets. Do
not use engine coolant or other types
of antifreeze as these may damage the
paint finish.
Do not let your parking brake freeze
Under some conditions your parking
brake can freeze in the engaged position.
This is most likely to happen when
there is an accumulation of snow or
ice around or near the rear brakes or
if the brakes are wet. If there is a risk
the parking brake may freeze, apply
it only temporarily while you put the
gear selector lever in P and block the
rear wheels so the car cannot roll. Then
release the parking brake.

07
7-7
WARNING
Your vehicle is equipped
with a pressurized coolant
reserve tank. NEVER remove
the engine coolant reservoir
tank/radiator cap or the drain plug while the engine and
radiator are HOT. Hot coolant
and steam may blow out under
pressure, causing serious
injury.
Turn the engine off and wait until the
engine cools down. Use extreme care
when removing the engine coolant
reservoir tank/radiator cap. Wrap
a towel or thick rag around it, and
turn it counterclockwise slowly to
release some of the pressure from the
system. Step back while the pressure is
released.
When you are sure all the pressure has
been released, continue turning the cap
counterclockwise to remove it.
6. If you cannot find the cause of the overheating, wait until the engine
temperature has returned to normal.
Then, if coolant has been lost,
carefully add coolant to the reservoir
to bring the fluid level in the reservoir
up to the halfway mark.
7. Proceed with caution, keeping alert
for further signs of overheating. If
overheating happens again, call
an authorized HYUNDAI dealer for
assistance.
NOTICE
• Serious loss of coolant indicates a
leak in the cooling system and we
recommend the system be checked
by an authorized HYUNDAI dealer.
• When the engine overheats from
low engine coolant, suddenly adding
engine coolant may cause cracks
in the engine. To prevent damage,
add engine coolant slowly in small
quantities.
• If there is overheating, park your
vehicle in a safe place and do not
turn off the engine until the cooling
fan stops. The engine might get stuck
due to sudden increase of water
temperature.
• Turn off the engine if the cooling fan
does not rotate.

07
7-21
BasIC trouBleshootIng guIDe
SYMPTOM
PROBABLE CAUSE
Starter won’t function
Engine turns over but will not start
Engine misfires
Engine overheats
Engine stops while driving driving
Fuel consumption is excessive
Brake pedal is spongy
Braking power is insufficient
Steering wheel is heavy
Steering wheel shakes
Steering wheel pulls to one side while driving
Vehicle pulls to one side while braking
Tire wear is abnormal
Charge warning light comes on while driving
Wipers, horn or lights won’t funciton
Battery discharge is excessive
Engine overheating O
Low fuel level O O
Fuel lines clogged O O
Fuel pump defective O O
Strainer clogged O O
Rich mixture O O O Water intrusion into fuel O O O
Coolant leakage OHigh idle speed O
Engine oil insufficient or defective O O
Battery fluid shortage O O
Battery discharged O O O
Battery terminal poor contact O O
Starter or ignition switch malfunction O
Ignition timing incorrect O O O Spark plugs deteriorated O O Spark plugs defective O

Engine Compartment .................................................................................... 8-3
Maintenance Services ................................................................................... 8-5
Owner’s Responsibility ............................................................................................ 8-5
Owner Maintenance Precautions ............................................................................ 8-5
Owner Maintenance ...................................................................................... 8-6
Owner Maintenance Schedule ................................................................................ 8-6
Scheduled Maintenance Services ................................................................ 8-8
Maintenance Schedule (Smartstream G1.6 T-GDI) ................................................8-8
Maintenance Schedule (Smartstream G2.5 GDI) ..................................................8-12
Maintenance Schedule (Smartstream G2.5 T-GDI) ...............................................8-16
Explanation of Scheduled Maintenance Items ..........................................8-20
Engine Oil ..................................................................................................... 8-23
Checking the Engine Oil Level ............................................................................... 8-23
Checking the Engine Oil and Filter ....................................................................... 8-25
Engine Coolant ............................................................................................. 8-26
Checking the Engine Coolant Level ...................................................................... 8-26
Changing Engine Coolant ...................................................................................... 8-28
Brake Fluid .................................................................................................... 8-29
Checking the Brake Fluid Level ............................................................................. 8-29
Washer Fluid ................................................................................................. 8-30
Checking the Washer Fluid Level .......................................................................... 8-30
Air Cleaner ..................................................................................................... 8-31
Filter Replacement .................................................................................................. 8-31
Climate Control Air Filter ............................................................................. 8-33
Filter Inspection...................................................................................................... 8-33
Filter Replacement ................................................................................................. 8-33
Wiper Blades ................................................................................................ 8-34
Blade Inspection .................................................................................................... 8-34
Blade Replacement ................................................................................................ 8-34
Battery .......................................................................................................... 8-36
For Best Battery Service ........................................................................................ 8-36
Battery Recharging ................................................................................................ 8-37
Reset Features ........................................................................................................ 8-37
8. Maintenance
8

Maintenance
8-6
WARNING
Performing maintenance work on a
vehicle can be dangerous. If you lack
sufficient knowledge and experience or
the proper tools and equipment to do
the work, have it done by an authorized
HYUNDAI dealer.
ALWAYS follow these precautions for
performing maintenance work: • Park your vehicle on level ground,
move the shift button into the P
(Park) position, place the ignition
switch in the LOCK/OFF position.
• Block the tires (front and back) to
prevent the vehicle from moving.
Remove loose clothing or jewelry
that can become entangled in
moving parts.
• If you must run the engine during
maintenance, do so out doors or in
an area with plenty of ventilation.
• Keep flames, sparks, or smoking
materials away from the battery and
fuel-related parts. The following lists are vehicle checks and
inspections that should be performed
by the owner or an authorized HYUNDAI
dealer at the frequencies indicated to
help ensure safe, dependable operation
of your vehicle.
Any adverse conditions should be
brought to the attention of your dealer as soon as possible.
These Owner Maintenance vehicle
checks are generally not covered by
warranties and you may be charged for
labor, parts and lubricants used.
Owner Maintenance Schedule
When you stop for fuel: •
Check the coolant level in the engine
coolant reservoir.
• Check the windshield washer fluid
level.
• Check the for low or under-inflated
tires.
WARNING
Be careful when checking your engine
coolant level when the engine is hot.
This may result in coolant being blown
out of the opening and cause serious
burns and other injuries.
ownEr maintEnanCE

08
8 -7
While operating your vehicle: •
Note any changes in the sound of the
exhaust or any smell of exhaust fumes
in the vehicle.
• Check for vibrations in the steering
wheel. Notice if there is any increased
steering effort or looseness in the
steering wheel, or change in its
straight-ahead position.
• Notice if your vehicle constantly turns
slightly or “pulls” to one side when
traveling on smooth, level road.
• When stopping, listen and check for
unusual sounds, pulling to one side,
increased brake pedal travel or “hard-
to-push” brake pedal.
• If any slipping or changes in the
operation of your transmission occurs,
check the transmission fluid level.
• Check the automatic transmission P
(Park) function.
• Check the parking brake.
• Check for fluid leaks under your
vehicle (water dripping from the air
conditioning system during or after use is normal).
At least monthly: • Check coolant level in the engine
coolant reservoir.
• Check the operation of all exterior
lights, including the brake lights, turn
signals and hazard warning flashers.
• Check the inflation pressures of all
tires including the spare for tires that
are worn, show uneven wear, or are damaged.
• Check for loose wheel lug nuts. At least twice a year:
(i.e., every Spring and Autumn) •
Check radiator, heater and air
conditioning hoses for leaks or damage.
• Check windshield washer spray and
wiper operation. Clean wiper blades
with a clean cloth dampened with
washer a fluid.
• Check headlamp alignment.
• Check muffler, exhaust pipes, shields and clamps.
• Check the seat belts for wear and function.
At least once a year: • Clean body and door drain holes.
• Lubricate door hinges and hood hinges.
• Lubricate door and hood locks and
latches.
• Lubricate door rubber weather strips.
• Lubricate door checker.
• Check the air conditioning system.
• Inspect and lubricate automatic
transmission linkage and controls.
• Clean the battery and terminals.
• Check the brake fluid level.

08
8-21
Engine Coolant
The coolant should be changed at the
intervals specified in the maintenance schedule.
Automatic Transmission Fluid
Automatic Transmission Fluid should
be replaced by an authorized HYUNDAI
dealer at the intervals specified in the
maintenance schedule.
Information
Automatic transmission fluid color is red
when new. As the vehicle is driven, the automatic transmission fluid will begin to look
darker. This is a normal condition and you
should not judge the need to replace the
fluid based upon the changed color.
NOTICE
The use of a non-specified fluid could
result in transmission malfunction
and failure. Use only the specified
automatic transmission fluid (refer
to “Recommended Lubricants and
Capacities” in chapter 2).
Brake Hoses and Lines
Visually check for proper installation,
chafing, cracks, deterioration and any
leakage. Replace any deteriorated or
damaged parts immediately.
Brake Fluid
Check the brake fluid level in the brake
fluid reservoir. The level should be
between the MIN and the MAX marks
on the side of the reservoir. Use only
hydraulic brake fluid conforming to DOT
4 specification.
Parking Brake
Inspect the parking brake system
including the parking brake pedal and cables.
Dual clutch transmission fluid (if equipped)
Inspect the dual clutch transmission fluid
according to the maintenance schedule.
Brake Discs, Pads, Calipers and
Rotors
Check the pads for excessive wear, discs
for run out and wear, and calipers for
fluid leakage.
Exhaust Pipe and Muffler
Visually inspect the exhaust pipes,
muffler and hangers for cracks,
deterioration, or damage. Start
the engine and listen carefully for
any exhaust gas leakage. Tighten
connections or replace parts as
necessary.