2018 Hyundai Sonata Plug-in Hybrid Owner's Manual

7-14
Maintenance
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Engine oil and filter
The engine oil and filter should be
changed at the intervals specified in
the maintenance schedule. If the car
is being driven in severe conditions,
more frequent oil and filter changes
are required.
HSG (Hybrid starter & genera-
tor) belt
The HSG belt should be changed at
the intervals specified in the mainte-
nance schedule.
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.
Fuel lines, fuel hoses and con-
nections
Check the fuel lines, fuel hoses and
connections for leakage and dam-
age. Have an authorized HYUNDAI
dealer replace any damaged or leak-
ing parts immediately.
Vapor hose and fuel filler cap
The vapor hose and fuel filler cap
should be inspected at those inter-
vals 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.

7-15
7
Maintenance
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 mainte-
nance 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 accor-
dance to the scheduled maintenance
at the beginning of this chapter.
Automatic transmission fluid color
is basically red.
As the vehicle is driven, the auto-
matic 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.
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.
Parking brake
Inspect the parking brake system
including the parking brake pedal
and cables.
NOTICE
The use of a non-specified fluid
could result in transmission mal-
function and failure. Use only the
specified automatic transmission
fluid (refer to "Recommended
Lubricants and Capacities" in
chapter 8).
CAUTION

7-16
Maintenance
Brake discs, pads, calipers
and rotors
Check the pads for excessive wear,
discs for run out and wear, and
calipers for fluid leakage.
For more information on checking
the pads or lining wear limit, refer to
the HYUNDAI web site.
(http://ser
vice.hyundai-motor.com)
Exhaust pipe and muffler
Visually inspect the exhaust pipes,
muffler and hangers for cracks, dete-
rioration, or damage. Start the
engine and listen carefully for any
exhaust gas leakage. Tighten con-
nections or replace parts as neces-
sary.
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 exces-
sive free-play in the steering wheel.
Check the linkage for bends or dam-
age. 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.

7-17
7
Maintenance
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Checking the engine oil level
1. Follow all of the oil manufacturer’s
precautions.
2. Be sure the vehicle is on level ground in P (Park) with the park-
ing brake set and the wheels
blocked.
3. Turn the engine on and allow the engine to reach normal operating
temperature.
4. Turn the hybrid system 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. 6. Pull the dipstick out again and
check the level. The level should
be between F and L.
7. If it is near or at L, add enough oil to bring the level to F. 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
NOTICE
OLFH076002

7-18
Maintenance
Use only the specified engine oil
(refer to "Recommended
Lubricants and Capacities" in
chapter 8).
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.
NOTICE
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 pro-
longed 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.
WARNING
OLFH074003

7-19
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 engine/inverter
coolant level
OLFH077005
OLFH074006
■ Radiator cap
■Inverter coolant cap
Never remove the
radiator 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.
Turn the hybrid system off and
wait until the engine cools
down. Use extreme care when
removing the radiator cap
and/or inverter coolant 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.
WARNING

7-20
Maintenance
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. The electric motor for the cooling fan
is controlled by engine coolant tem-
perature, 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.
Engine coolant
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 sys-
tem inspection.
i
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.
WARNING
OLF074006N

7-21
7
Maintenance
Inverter coolant
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 enough
distilled (deionized) water to bring
the level to the MAX mark, but do not
overfill. If frequent additions are
required, we recommend that you
see an authorized HYUNDAI dealer
for a cooling system inspection.
Recommended coolant
When adding coolant, use onlydeionized water, distilled water or
soft 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/ hybrid system damage.
The engine in your vehicle has alu- minum 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 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. 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
OLFH074006