HYUNDAI SONATA HYBRID 2021 Owners Manual

Maintenance
8-12
Maintenance ItemMaintenance
operation Maintenance Intervals Driving
condition
Rear brake disc/pads IMore frequently C, D, G, F
Steering gear box,
linkage & boots/ lower
arm ball joint, upper arm
ball joint I
More frequently C, D, E, F, G,
H, I
Drive shafts and boots IEvery 7,500 miles (12,000 km) or
6 months C, D, E, F,
G, H, I, J
Automatic transmission
fluid R
Every 60,000 miles (96,000 km) A, C, D, E, F,

G, H, I, K
Parking brake IMore frequently C, D, G, H
Severe driving conditions
A. Repeatedly driving short distance of less than 5 miles (8 km) in normal temperature
or less than 10 miles (16 km) in freezing temperature
B. Extensive engine idling or low speed driving for long distances
C. Driving on rough, dusty, muddy, unpaved, graveled or saltspread roads
D. Driving in areas using salt or other corrosive materials or in very cold weather
E. Driving in sandy areas
F. Driving in heavy traffic area over 90°F (32°C)
G. Driving on uphill, downhill, or mountain road
H. Towing a Trailer, or using a camper, or roof rack
I. Driving as a patrol car, taxi, other commercial use or vehicle towing
J. Driving over 106 mph (170 km/h)
K. Frequently driving in stop-and-go conditions

08
8-13
Engine Oil and Filter
The engine oil and filter should be
changed at the intervals specified in the
maintenance schedule. If the vehicle
is being driven in severe conditions,
more frequent oil and filter changes are
required.
HSG (Hybrid Starter & Generator)
Belt
The HSG belt should be changed at the
intervals specified in the maintenance
schedule.
Fuel Lines, Fuel Hoses and
Connections
Check the fuel lines, fuel hoses and
connections for leakage and damage.
Have an authorized HYUNDAI dealer
replace any damaged or leaking parts
immediately.
Fuel Filter
A clogged filter can limit the speed
at which the vehicle may be driven,
damage the emission system and cause
multiple issues such as hard starting. If
an excessive amount of foreign matter
accumulates in the fuel tank, the
filter may require replacement more
frequently. After installing a new filter,
run the engine for several minutes,
and check for leaks at the connections.
Fuel filters should be installed by an
authorized HYUNDAI dealer.
Vapor Hose and Fuel Filler Cap
The vapor hose and fuel filler cap should
be inspected at those intervals specified
in the maintenance schedule. Make sure
a new vapor hose or fuel filler cap is
correctly replaced.
Air Cleaner Filter
A genuine HYUNDAI air cleaner filter
is recommended when the filter is
replaced.
Spark Plugs
Make sure to install new spark plugs of
the correct heat range.
Cooling System
Check cooling system components, such
as radiator, coolant reservoir, hoses and
connections for leakage and damage.
Replace any damaged parts.
Engine Coolant/Inverter Coolant
The coolant should be changed at the
intervals specified in the maintenance
schedule.
Automatic Transmission Fluid
Automatic transmission fluid should
not be checked under normal usage
conditions. But in severe conditions, the
fluid should be changed at an authorized
HYUNDAI dealer in accordance to the
scheduled maintenance at the beginning
of this chapter.
EXPLANATION OF SCHEDULED MAINTENANCE ITEMS

Maintenance
8-14
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).
Engine Clutch Actuator Fluid
The engine clutch actuator fluid level
should be inspected or replaced to the
intervals specified in the maintenance
schedule.
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.
Brake Discs, Pads, Calipers and
Rotors
Check the pads, the disc, and the rotor
for any excessive wear-out. Inspect
calipers for any 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.
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 hybrid
system 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 damage.

08
8-15
Checking the Engine Oil Level
1. Follow all of the oil manufacturer’s
precautions.
2. Be sure the vehicle is on the level
ground in P (Park) with the parking
brake set and the wheels blocked.
3. Turn the engine on and allow the
engine to reach normal operating
temperature.
4. Turn the engine off and wait about
five minutes for the oil to return to the
oil pan.
5. Pull the dipstick out, wipe it clean, and
re-insert it fully.
ODN8H089002
6. Pull the dipstick out again and check
the level. The level should be between
F (Full) and L (Low).
ODN8H089003
7. If it is near or at L, add enough oil to
bring the level to F.
Use only the specified engine oil (Refer
to “Recommended Lubricants and
Capacities” section in chapter 2).
NOTICE
To prevent damage to your engine:
• Do not overfill with engine oil. Add oil
in small quantities and recheck level
to ensure engine is not overfilled.
• Do not spill engine oil when adding
or changing engine oil. Use a funnel
to help prevent oil from being spilled
on engine components. Wipe off
spilled oil immediately.
ENGINE OIL

Maintenance
8-16
Checking the Engine Oil and
Filter
Have engine oil and filter changed by an authorized HYUNDAI dealer according
to the Maintenance Schedule at the
beginning of this chapter.
WARNING
CALIFORNIA PROPOSITION 65
WARNING
Engine oil contains chemicals known to
the State of California to cause cancer,
birth defects and reproductive harm.
Used engine oil may cause irritation or
cancer of the skin if left in contact with
the skin for prolonged periods of time.
Always protect your skin by washing
your hands thoroughly with soap and
warm water as soon as possible after
handling used oil.

08
8-17
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.
Checking the Coolant Level
„„Engine coolant
ODN8H089054L
„„Inverter coolant
ODN8H089053L
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 side of the coolant reservoir when
the engine is cool.If the coolant level is low, add the
selected anti-freeze according to the proper coolant mix ratio to bring the level to the MAX mark, but do not overfill. If
frequent additions are required, see an
authorized HYUNDAI dealer for a cooling
system inspection.
„„Engine coolant cap
ODN8H089055
„„Inverter coolant cap
ODN8H089056
WARNING
Never remove the engine coolant cap and/or inverter
coolant cap or the drain plug
while the engine and radiator
are hot. Hot coolant and steam
may blow out under pressure,
causing serious injury.
ENGINE COOLANT/INVERTER COOLANT

Maintenance
8-18
Turn the vehicle off and wait until
the engine cools down. Use extreme
care when removing the engine
coolant cap and/or inverter coolant
cap. Wrap a thick towel around it,
and turn it counterclockwise slowly
while the pressure is released from
the cooling system. When you are sure
all the pressure has been released,
using a thick towel, continue turning
counterclockwise to remove it.
Information
The engine coolant and/or inverter coolant
level is influenced by the hybrid system
temperature. Before checking or refilling
the engine coolant and/or inverter coolant,
turn the hybrid vehicle off.
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.
Keep hands, clothing and tools away
from the rotating fan blades of the
cooling fan.
Always turn off the vehicle unless the
vehicle has to be inspected with the
engine on. Be cautious as the cooling
fan may operate if the negative (-)
battery terminal is not disconnected.
WARNING
Make sure the coolant cap is properly
closed after refilling coolant. Otherwise
the engine could be overheated while
driving.
„„Engine compartment front view
OOSH089010L
1. Check if the coolant cap label is
straight In front.
„„Engine compartment rear view
ODN8H089044
2. Make sure that the tiny protrusions
inside the coolant cap is securely
interlocked.

08
8-19
Recommended coolant
• When adding coolant, use only
deionized water, distilled water or soft
water for your vehicle and never mix
hard water in the coolant filled at the
factory.
• An incorrect coolant mixture can
result in severe malfunction or
engine/hybrid system damage.
• The engine in your vehicle has
aluminum engine parts and must be
protected by an phosphate-based
ethylene glycol 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.
For mixing percentage, refer to the
following table:
Ambient
Temperature Mixture Percentage
(volume)
Antifreeze Water
5°F (-15°C) 3565
-13°F (-25°C) 4060
-31°F (-35°C) 5050
-49°F (-45°C) 6040
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
(-35°C) and higher.
Changing 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 engine coolant
cap and/or inverter coolant cap before
refilling the coolant to prevent the
coolant from overflowing into engine
parts, such as the alternator.

Maintenance
8-20
Checking the Hybrid Starter &
Generator (HSG) Belt
Have the Hybrid Starter & Generator
(HSG) belt inspected or replaced
according to the Maintenance Schedule
in this chapter by an authorized
HYUNDAI dealer.
CAUTION
When the HSG belt is worn out or
damaged, replace the belt.
Otherwise, it may cause engine
overheating or battery discharge.
WARNING
• Turn the vehicle off while you inspect
the engine or Hybrid Starter &
Generator (HSG) belt. Otherwise it
may result in serious injury.
• Keep hands, clothing etc. away from
the Hybrid Starter & Generator (HSG)
belt.
Checking the Brake Fluid Level
ODN8H089005
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 thoroughly to prevent
brake fluid contamination.
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.
WARNING
If the brake system requires frequent
additions of fluid this could indicate
a leak in the brake system. Have the
vehicle inspected by an authorized
HYUNDAI dealer.
HYBRID STARTER &
GENERATOR (HSG) BELT BRAKE FLUID

08
8-21
WASHER FLUID
Checking the Washer Fluid Level
ODN8H089006
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 flame 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.
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.
NOTICE
• Do not allow brake fluid to contact
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
disposed of properly.
• Do not use the wrong kind of brake
fluid. A few drops of mineral 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” section in chapter 2).