2020 Hyundai Sonata coolant reservoir

08
8-21
The high-pressure cooling system has a
reservoir filled with year-round antifreeze
coolant. The reservoir is filled at the
factory.
Check the antifreeze protection and
coolant level at least once a year, at
the beginning of the winter season and
before traveling to a colder climate.
NOTICE
• 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.
• Do not drive with no engine coolant.
It may cause water pump failure and
engine seizure, etc.
Checking the Engine Coolant
Level
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Check the condition and connections
of all cooling system hoses and
heater hoses. Replace any swollen or
deteriorated hoses.
The coolant level should be filled
between the F and the L marks on the
side of the coolant reservoir when the
engine is cool. If the coolant level is low, add enough
distilled (deionized) water to bring the
level to the F mark, but do not overfill. If
frequent additions are required, see an
authorized HYUNDAI dealer for a cooling
system inspection.
Recommended engine coolant
• When adding coolant, use only
distilled (deionized) water for your
vehicle and never mix hard water in
the coolant filled at the factory.
• An improper coolant mixture can result in severe malfunction or engine
damage.
• The engine in your vehicle has aluminum engine parts and must be
protected by an ethylene-glycol with
phosphate based coolant to prevent
corrosion and freezing.
• Do not use alcohol or methanol coolant or mix them with the specified
coolant.
• Do not use a solution that contains more than 60% antifreeze or less than
35% antifreeze, which would reduce
the effectiveness of the solution.
ENGINE COOLANT

Maintenance8-22
For mixing percentage, refer to the
following table:
Ambient
Temperature Mixture Percentage
(volume)
Antifreeze Water
5°F (-15°C) 35 65
-

13°F (-25°C) 40 60
-31°F (-35°C) 50 50
-49°F (-45°C) 60 40
Information
If in doubt about the mix ratio, a 50%
water and 50% antifreeze mix is the
easiest to mix together as it will be the
same quantity of each. It is suitable to use
for most temperature ranges of - 31°F and
higher.
WARNING
Make sure the coolant cap is properly
closed after refilling coolant. Otherwise
the engine could be overheated while
driving.
Engine room front viewEngine room front view
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1. Check if the coolant cap label is straight In front.
2. Make sure that the tiny protrusions inside the coolant cap is securely
interlocked.
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WARNING
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 thick towel around it, and turn it
counterclockwise slowly to the first
stop. Step back while the pressure is
released from the cooling system. When
you are sure all the pressure has been
released, press down on the cap, using
a thick towel, and continue turning
counterclockwise to remove it.

08
8-23
WARNING
The electric motor for the
cooling fan may continue to
operate or start up when the
engine is not running and can
cause serious injury. Keep
hands, clothing and tools away
from the rotating fan blades of
the cooling fan.
The electric motor for the cooling
fan is controlled by engine coolant
temperature, refrigerant pressure and
vehicle speed. As the engine coolant
temperature decreases, the electric
motor will automatically shut off. This
is a normal condition. If your vehicle is
equipped with GDI, the electric motor
for the cooling fan may begin to operate
at any time and continue to operate until
you disconnect the negative battery
cable.
Changing Engine Coolant
Have coolant changed by an authorized
HYUNDAI dealer according to the
Maintenance Schedule at the beginning
of this chapter.
WARNING
Do not use engine coolant or antifreeze
in the washer fluid reservoir.
Engine coolant can severely obscure
visibility when sprayed on the
windshield and may cause loss of
vehicle control resulting in an accident.
Engine coolant may also cause damage
to paint and body trim.
NOTICE
To prevent damage to engine parts, put
a thick towel around the radiator cap
before refilling the coolant to prevent
the coolant from overflowing into
engine parts, such as the alternator.

08
8-25
Checking the Washer Fluid Level
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Check the fluid level in the washer fluid
reservoir and add fluid if necessary. Plain
water may be used if washer fluid is not
available. However, use washer solvent
with antifreeze characteristics in cold
climates to prevent freezing.
WARNING
To prevent serious injury or death, take
the following safety precautions when
using washer fluid:
• Do not use engine coolant or
antifreeze in the washer fluid
reservoir.
Engine coolant can severely obscure
visibility when sprayed on the
windshield and may cause loss
of vehicle control resulting in an
accident or damage to paint and
body trim.
• Do not allow sparks or flames to
contact the washer fluid or the
washer fluid reservoir. Washer fluid
may contain alcohol and can be
flammable.
• Do not drink washer fluid and avoid
contact with skin. Washer fluid is
harmful to humans and animals.
• Keep washer fluid away from
children and animals.
WASHER FLUID