2023 HYUNDAI NEXO cooling

6-9
What to do in an emergency
1. Pull off the road and stop as soonas it is safe to do so.
2. Shift to P (Park) and set the park- ing brake. If the air conditioning is
on, turn it off.
3. If coolant is running out under the vehicle or steam is coming out
from the hood, stop the vehicle.Do not open the hood until the
coolant has stopped running or
the steaming has stopped. If there
is no visible loss of coolant and no
steam, leave the vehicle running
and check to be sure the vehicle
cooling fan is operating. If the fan
is not running, turn the vehicle off. 4. Check for coolant leaking from the
radiator, hoses or under the vehi-
cle. (If the air conditioning had
been in use, it is normal for cold
water to be draining from it when
you stop.)
5. If coolant is leaking out, stop the vehicle immediately and call the
nearest authorized HYUNDAI
dealer for assistance.
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6
While the vehicle is
running, keep hands,
clothing and tools
away from the mov-
ing parts such as the
cooling fan to prevent
serious injury.
WARNING
Your vehicle is equipped with a pres-
surized coolant
reserve tank. NEVER
remove the coolant
reserve tank cap or the radiatordrain plug while the radiator is
HOT. Hot coolant and steam
may blow out under pressure,
causing serious injury.
Turn the vehicle off and wait
until the vehicle cools down.
Use extreme care when remov-
ing the coolant reserve tank
cap. Wrap a towel or thick rag
around it, and turn it counter-
clockwise slowly to release
some of the pressure from the
system. Step back while thepressure is released.
When you are sure all the pres-
sure has been released, contin-ue turning the cap counter-
clockwise to remove it.
WARNING

6-10
6. If you cannot find the cause of the
overheating, wait until the radiator
temperature has returned to nor-
mal. Then, if coolant has beenlost, 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 overheat-
ing. If overheating happens again,
call an authorized HYUNDAI deal-
er for assistance.
What to do in an emergency
Serious loss of coolant indi- cates a leak in the cooling sys-
tem and should be checked as
soon as possible by an author-
ized HYUNDAI dealer.
CAUTION

7
Maintenance
7
Maintenance
Fuel Cell Power Module Compartment ...............7-3
Maintenance Services ...........................................7-4Owner's Responsibility .....................................................7-4
Owner Maintenance Precautions..................................7-4
Owner Maintenance ..............................................7-5 Owner Maintenance Schedule .......................................7-6
Scheduled Maintenance Services........................7-7 Normal Maintenance Schedule ......................................7-8
Maintenance Under Severe Usage Conditions ........7-10
Explanation of Scheduled Maintenance Items ..7-12
Device Cooling Coolant .......................................7-13 Checking the Coolant Level ..........................................7-13
Changing Coolant ............................................................7-15
Stack Cooling Coolant .........................................7-16 Checking the Coolant Level ..........................................7-16
Changing Coolant ............................................................7-18
Brake Fluid ............................................................7-19 Checking the Brake Fluid Level ...................................7-19
Washer Fluid .........................................................7-20 Checking the Washer Fluid Level................................7-20
Air Cleaner ............................................................7-20 Filter Replacement ..........................................................7-20
Climate Control Air Filter ....................................7-22 Filter Inspection ...............................................................7-22 Wiper Blades.........................................................7-24
Blade Inspection ..............................................................7-24
Blade Replacement .........................................................7-24
12V Battery ...........................................................7-27 Battery Recharging ........................................................7-28
Reset Features.................................................................7-28
Tires and Wheels .................................................7-29 Tire Care ............................................................................7-29
Recommended Cold Tire Inflation Pressures ...........7-30
Check Tire Inflation Pressure ......................................7-31
Tire Rotation.....................................................................7-32
Wheel Alignment and Tire Balance ............................7-33
Tire Replacement ............................................................7-33
Wheel Replacement ........................................................7-34
Tire Traction .....................................................................7-34
Tire Maintenance ............................................................7-34
Tire Sidewall Labeling ....................................................7-34
Tire Terminology and Definitions................................7-38
All Season Tires ...............................................................7-42
Summer Tires ...................................................................7-42
Snow Tires ........................................................................7-42
Radial-Ply Tires ...............................................................7-42
Low Aspect Ratio Tires..................................................7-43
7

7-3
7
Maintenance
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1. Brake fluid reservoir
2. Air cleaner
3. Fuse box
4. Windshield washer fluid reservoir
5. Device cooling coolant reservoir
6. Traction motor radiator cap
7. Stack cooling coolant reservoir
8. Fuel cell stack radiator cap
OFE078001
The actual fuel cell power module compartment in the vehicle may differ from the illus- tration.

7-6
Maintenance
Owner Maintenance Schedule
When you stop for fuel:
• Check for both fuel cell stack andDevice cooling coolant level in
coolant reservoir.
Check the windshield washer fluid level.
Look for low or under-inflated tires.
While operating your vehicle:
Check for vibrations in the steering wheel. Notice if there is any
increased steering effort or loose-
ness in the steering wheel, or
change in its straight-ahead posi-tion.
Notice if your vehicle constantly turns slightly or "pulls" to one side
when traveling on smooth, levelroad.
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 reduction gear
occurs, check the reduction gear
fluid level.
Check the reduction gear 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 coolantreservoir.
Check the operation of all exterior lights, including the brake lights,
turn signals and hazard warning
flashers.
Check the inflation pressures of all 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 Fall)
Check radiator, heater and air con- ditioning hoses for leaks or dam-
age.
Check windshield washer spray and wiper operation. Clean wiper
blades with clean cloth dampened
with washer fluid.
Check headlamp alignment.
Check the seat belts for wear and function.
Be careful when checking the
coolant level when the fuel cell
power module is hot. Scalding
hot coolant and steam may
blow out under pressure. This
could cause burns or other seri-
ous injury.
WARNING

7-8
Maintenance
Normal Maintenance Schedule
Months1224364860728496108120132144156168180
Miles×1,00061218243036424854606672788490
Km×1,000102030405060708090100110120130140150
Hydrogen system
(Check the hydrogen leakage)Inspect every 10,000 km (6,000 miles) or 24 months
Air cleaner filterReplace every at 20,000 km (12,000) miles
Device cooling coolantAt first, replace at 200,000 km (120,000 miles) or 10 years :
Thereafter, replace every 48,000 km (30,000 miles) or 24 months
Stack cooling coolantReplace every at 60,000 km (36,000 miles) or 36 months
Ion filterReplace every at 60,000 km (36,000 miles) or 36 months
Reduction gearNo check, No service required
Air conditioner refrigerant/ compressorIIIIIIIIIIIIIII
Cooling system hoses and connec- tions IIIIIIIIIIIIIII
Brake lines, hoses and connections (including booster)IIIIIIIIIIIIIII
Clutch (if equipped) and brake
pedal free playIIIIIIIIIIIIIII
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 necessary
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 fluidR120,000 km (72,000 miles)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
MaintenanceE
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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.