maintenance HYUNDAI NEXO 2021 Owner's Manual

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Maintenance
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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 cli-
mate.Checking the Coolant Level
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 MAX and the MIN
marks on the rear side of the coolant
reservoir when the parts in the fuel
cell power module compartment is
cool.
If the coolant level is low, add enough
distilled (deionized) water to bring
the level to the MAX mark, but do not
overfill. If frequent additions are
required, you see an authorized
HYUNDAI dealer for a cooling sys-
tem inspection.
Recommended 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
electric devices damage.
Do not use alcohol or methanol coolant or mix them with the spec-
ified 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.
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Maintenance
For mixing percentage, refer to the
following table:
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.
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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
Never remove the
radiator cap or the
drain plug while the
radiator is hot. Hot
coolant and steam
may blow out under pressure,
causing serious injury.
WARNING
OFE078004
Turn the vehicle off and wait
until the parts in the fuel cell
power module compartment
cools down. Use extreme care
when removing the 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 sys-
tem. When you are sure all the
pressure has been released,
press down on the cap, using a
thick towel, and continue turn-
ing counterclockwise to remove
it.

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MaintenanceThe electric motor for the cooling fan
is controlled by coolant temperature,
refrigerant pressure and vehicle
speed. As the coolant temperature
decreases, the electric motor will
automatically shut off. This is a nor-
mal condition.
Changing Coolant
Have coolant changed by an author-
ized HYUNDAI dealer according to
the Maintenance Schedule at the
beginning of this chapter.To prevent damage to parts in the
fuel cell power module compart-
ment, put a thick towel around the
coolant cap before refilling the
coolant to prevent the coolant
from overflowing into parts in the
fuel cell power module compart-
ment.
NOTICE
The electric motor for
the cooling fan may
continue to operate
or start up when the
vehicle is not running
and can cause serious injury.
Keep hands, clothing and tools
away from the rotating fan
blades of the cooling fan.
WARNING
Do not use coolant or antifreeze
in the washer fluid reservoir.
Coolant can severely obscure
visibility when sprayed on the
windshield and may cause loss
of vehicle control resulting in an
accident.
Coolant may also cause dam-
age to paint and body trim.
WARNING

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Maintenance
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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 cli-
mate.Checking the Coolant Level
Check the condition and connections
of all cooling system hoses and
heater hoses. Replace any swollen
or deteriorated hoses.
When replacing any part of the cool-
ing system there may be loss of
coolant. In that case, fill with an
exclusive coolant for the fuel cell.
When replacing the ion filter car-
tridge, replace the whole stack
coolant.
The coolant level should be filled
between F (MAX) and L (MIN) marks
on the side of the coolant reservoir
when the fuel cell power module is
cool. If the stack cooling coolant level is
low, add enough exclusive coolant
for fuel cell stack to provide protec-
tion against freezing and corrosion in
the authorized HYUNDAI dealer.
In addition, whenever replacing the
ion filter cartridge, add enough exclu-
sive coolant for fuel cell stack.
OFE078005

Stack cooling coolant
When adding stack coolingcoolant, use only exclusive coolant
for fuel cell stack in authorized
HYUNDAI dealer and never mix
any water or liquid.
An improper coolant mixture can result in severe malfunction or
electric devices damage.
If the vehicle is damaged by adding unspecified liquid except exclusive
coolant for fuel cell stack, it will not
be covered by the warranty.
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Maintenance
Never remove the
radiator cap or the
drain plug while the
radiator is hot. Hot
coolant and steam
may blow out under pressure,
causing serious injury.
WARNING
OFE078006
Turn the vehicle off and wait
until the parts in the fuel cell
power module compartment
cools down. Use extreme care
when removing the 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 counterclock-
wise to remove it.

The electric motor for the cooling fan
is controlled by coolant temperature,
refrigerant pressure and vehicle
speed. As the coolant temperature
decreases, the electric motor will
automatically shut off. This is a nor-
mal condition.
Changing Coolant
For the fuel cell stack, an exclusive
coolant must be used . When chang-
ing the fuel cell stack coolant, we
recommend that coolant be changed
by an authorized HYUNDAI dealer
according to the Maintenance
Schedule at the beginning of this
chapter.To prevent damage to parts in the
fuel cell power module compart-
ment, put a thick towel around the
coolant cap before refilling the
coolant to prevent the coolant
from overflowing into parts in the
fuel cell power module compart-
ment.
NOTICE
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Maintenance
The electric motor for
the cooling fan may
continue to operate
or start up when the
vehicle is not running
and can cause serious injury.
Keep hands, clothing and tools
away from the rotating fan
blades of the cooling fan.
WARNING
Do not use coolant or antifreeze
in the washer fluid reservoir.
Coolant can severely obscure
visibility when sprayed on the
windshield and may cause loss
of vehicle control resulting in an
accident.
Coolant may also cause dam-
age to paint and body trim.
WARNING
Do not mix-up the caps of
device cooling coolant and
stack cooling coolant because
the fluid material is different. If
the cap is mixed, the fuel cell
system may be damage.
We recommend that you con-
sult an authorized HYUNDAI
dealer.
CAUTION

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Maintenance
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Checking the Brake Fluid
Level
Check the fluid level in the reservoir
periodically. The fluid level should be
between MAX and MIN marks on the
side of the reservoir.
Before removing the reservoir cap
and adding brake fluid, clean the
area around the reservoir cap thor-
oughly to prevent brake fluid contam-
ination. If the level is low, add the specified
brake fluid to the MAX level. The level
will fall with accumulated mileage.
This is a normal condition associated
with the wear of the brake linings. If
the fluid level is excessively low, have
the brake system checked by an
authorized HYUNDAI dealer.
Do not allow brake fluid to con-
tact the vehicle’s body paint, as
paint damage will result.
Brake fluid, which has been exposed to open air for an
extended time should NEVER be
used as its quality cannot be
guaranteed. It should be dis-
posed of properly.
Do not use the wrong kind of brake fluid. A few drops of min-
eral based oil, such as engine
oil, in your brake system can
damage brake system parts.
Information
Use only the specified brake fluid
(refer to "Recommended Lubricants
and Capacities" in chapter 8).
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NOTICE
If the brake system requires fre-
quent additions of fluid this
could indicate a leak in the
brake system. Have the vehicle
inspected by an authorized
HYUNDAI dealer.
WARNING
Do not allow brake fluid to come
in contact with your eyes. If
brake fluid comes in contact
with your eyes, flush your eyes
with clean water for at least 15
minutes and get immediate
medical attention.
WARNING
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Maintenance
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Checking the Washer Fluid
Level
Check the fluid level in the washer
fluid reservoir and add fluid if neces-
sary. Plain water may be used if
washer fluid is not available.
However, use washer solvent with
antifreeze characteristics in cold cli-
mates to prevent freezing.
Filter Replacement
Faulty air cleaner filter has a direct
influence on reduction of the stack
output, etc. Replace the filter accord-
ing to the maintenance schedule.
OFE078008
To prevent serious injury or
death, take the following safety
precautions when using washer
fluid:
Do not use coolant or
antifreeze in the washer fluid
reservoir.
Coolant can severely obscure
visibility when sprayed on the
windshield and may cause
loss of vehicle control result-
ing in an accident or damage
to paint and body trim.
Do not allow sparks or flame
to contact the washer fluid or
the washer fluid reservoir.
Washer fluid may contain
alcohol and can be flamma-
ble.
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.
WARNING
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1. Loosen the air cleaner coverattaching clips and open the
cover. 2. Wipe the inside of the air cleaner.
3. Replace the air cleaner filter.
4. Lock the cover with the cover
attaching clips.
5. Check that the cover is firmly installed.
Information
If the vehicle is operated in extremely
dusty or sandy areas, replace the air
cleaner filter more often than the
usual recommended intervals (refer to
"Maintenance Under Severe Usage
Conditions" in this chapter).
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Maintenance
OFE078010OFE078009Do not drive with the air clean-
er filter removed. This will
result in excessive wear.
When removing the air clean-
er filter, be careful that dust or
dirt does not enter the air
intake, or damage may result.
Use HYUNDAI genuine parts,
use of non-genuine parts
could damage the air flow
sensor.
CAUTION

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Maintenance
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Filter Inspection
The climate control air filter should
be replaced according to the
Maintenance Schedule. If the vehicle
is operated in severely air-polluted
cities or on dusty rough roads for a
long period, it should be inspected
more frequently and replaced earlier.
When you replace the climate control
air filter, replace it performing the fol-
lowing procedure, and be careful to
avoid damaging other components.
1. With the glove box open, removethe stoppers on both sides to allow
the glove box to hang freely on the
hinges. 2. Remove the support rod (1).
OFE078011OFE078012