coolant HYUNDAI NEXO 2022 User Guide

7-8
Maintenance
Normal Maintenance Schedule
Months1224364860728496108120132144156168180
Miles×1,00061218243036424854606672788490
Km×1,000102030405060708090100110120130140150
Hydrogen system
(Check the hydrogen leakage)Inspect every 6,000 miles (10,000 km) or 24 months
Air cleaner filterReplace every at 12,000 (20,000 km) miles
Device cooling coolantAt first, replace at 120,000 miles (200,000 km) or 10 years :
Thereafter, replace every 30,000 miles (48,000 km) or 24 months
Stack cooling coolantReplace every at 36,000 miles (60,000 km) or 36 months
Ion filterReplace every at 36,000 miles (60,000 km) or 36 months
Reduction gearNo check, No service required
Air conditioner refrigerant/
compressorIIIIIIIIIIIIIII
Brake lines, hoses and connectionsIIIIIIIIIIIIIII
Brake discs and padsIIIIIIIIIIIIIII
Driveshaft and bootsIIIIIII
Front suspension ball jointsIIIIIIIIIIIIIII
Maintenance Intervals
Maintenance
Item
I : Inspect and if necessary, adjust, correct, clean or replace.
R : Replace

7-10
Maintenance
Maintenance Under Severe Usage Conditions
The following items must be serviced more frequently on cars normally used under severe driving conditions. Refer
to the chart below for the appropriate maintenance intervals.
R : Replace I : Inspect and, after inspection, clean, adjust, repair or replace if neces\
sary
Maintenance itemMaintenanceoperationMaintenance intervalsDriving condition
Hydrogen system
(Check the hydrogen leakage)IInspect more frequently
depending on the conditionC, D, F, G, J, L
Air cleaner filterIInspect more frequently
depending on the conditionC, D, E
Device cooling coolantRReplace more frequently
depending on the conditionC, D, E, F, J, K, L
Stack cooling coolantRReplace more frequently
depending on the conditionC, D, F, G, L
Ion filterRReplace more frequently
depending on the conditionC, D, F, G, L
Reduction gear fluidR72,000 miles (120,000 km)C, F, G, I, J
Air conditioner refrigerant/compressorIInspect more frequently
depending on the conditionC, D, F, G, L
Disc brakes and pads, calipers and rotorsIInspect more frequently
depending on the conditionC, D, E, G, H

7-12
Maintenance
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Cooling System
Check cooling system components,
such as radiator, coolant reservoir,
hoses and connections for leakage
and damage. Replace any damaged
parts.
Coolant
The coolant should be changed at
the intervals specified in the mainte-
nance schedule.
Reduction Gear Fluid
Inspect the reduction gear fluid
according to the maintenance sched-
ule.
Brake Hoses and Lines
Visually check for proper installation,
chafing, cracks, deterioration and
any leakage. Replace any deteriorat-
ed or damaged parts immediately.
Brake Fluid
Check 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 con-
forming to DOT 3 or DOT 4 specifi-
cation.
Brake Discs, Pads, Calipers
and Rotors
Check the pads for excessive wear,
discs for run out and wear, and
calipers for fluid leakage.
Suspension Mounting Bolts
Check the suspension connections
for looseness or damage. Retighten
to the specified torque.
Steering Gear Box, Linkage &
Boots/Lower Arm Ball Joint
With the vehicle stopped and the
vehicle off, check for excessive free-
play in the steering wheel. Check the
linkage for bends or damage. Check
the dust boots and ball joints for
deterioration, cracks, or damage.
Replace any damaged parts.
Drive Shafts and Boots
Check the drive shafts, boots and
clamps for cracks, deterioration, or
damage. Replace any damaged
parts and, if necessary, repack the
grease.
Air Conditioning Refrigerant
Check the air conditioning lines and
connections for leakage and dam-
age.

7-13
7
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.
OFE078003

7-14
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.
i
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.

7-15
7
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

7-16
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.
7-17
7
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
7-18
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

7-20
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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