2021 HYUNDAI SONATA spark plugs replace

06
6-145
Change to "winter weight" oil if
necessary
In some climates it is recommended that
a lower viscosity "winter weight" oil be
used during cold weather. See chapter 8
for recommendations. If you aren't sure
what weight oil you should use, consult
an authorized HYUNDAI dealer.
Check battery and cables
Winter puts additional burdens on the
battery system. Visually inspect the
battery and cables as described in
chapter 8. The level of charge in your
battery can be checked by an authorized
HYUNDAI dealer or a service station.
Check spark plugs and ignition
system
Inspect your spark plugs as described in
chapter 8 and replace them if necessary.
Also check all ignition wiring and
components to be sure they are not
cracked, worn or damaged in any way.
Use approved window washer anti-
freeze in system
To keep the water in the window washer
system from freezing, add an approved
window washer anti-freeze solution in
accordance with instructions on the
container. Window washer anti-freeze is
available from an authorized HYUNDAI
dealer and most auto parts outlets. Do
not use engine coolant or other types
of antifreeze as these may damage the
paint finish.
Do not let your parking brake freeze
Under some conditions your parking
brake can freeze in the engaged position.
This is most likely to happen when
there is an accumulation of snow or
ice around or near the rear brakes or
if the brakes are wet. If there is a risk
the parking brake may freeze, apply
it only temporarily while you put the
gear selector lever in P and block the
rear wheels so the car cannot roll. Then
release the parking brake.
Do not let ice and snow accumulate
underneath
Under some conditions, snow and ice
can build up under the fenders and
interfere with the steering. When driving
in severe winter conditions where this
may happen, you should periodically
check underneath the car to be sure the
movement of the front wheels and the
steering components is not obstructed.
Don't place foreign objects
or materials in the engine
compartment
Placement of foreign object or materials
which prevent cooling of the engine, in
the engine compartment, may cause a
failure or combustion. The manufacturer
is not responsible for the damage caused
by such placement.
To keep locks from freezing
To keep the locks from freezing, squirt
an approved de-icer fluid or glycerine
into the key opening. If a lock is covered
with ice, squirt it with an approved de-
icing fluid to remove the ice. If the lock
is frozen internally, you may be able to
thaw it out by using a heated key. Handle
the heated key with care to avoid injury.

Maintenance
8-8
Normal Maintenance Schedule (Smartstream G1.6 T-GDi)
MAINTENANCE INTERVALS
MAINTENANCE
ITEM Months 12 24 36 48 60 72 84 96 108 120 132 144 156
Miles×1,000 8 16 24 32 40 48 56 64 72 80 88 96 104 Km×1,000 13 26 39 52 65 78 91 104 117 130 143 156 169
Drive belts
*1
At first, inspect at 48,000 miles (78,000 km) or 72 months.
Thereafter, inspect every 8,000 miles (13,000 km) or 12 months
Engine oil and engine oil filter
*2
R R R R R R R R R R R R R
Fuel additives
*3
Add fuel additives every 8,000 miles (13,000 km) or 12 months
Air cleaner filter I I R I I R I I R I I R I
Air intake hose I I I I I I I I I I I I I
Spark plugs RR
Rotate tires Rotate every 8,000 miles (13,000 km)
Climate control air filter R R R R R R
Vacuum hose I I I I I I I I I I I I I
Engine coolant At first, replace at 120,000 miles or 120 months.
Thereafter, replace every 30,000 miles or 24 months
R: Replace or change.
I : Inspect and if necessary, adjust, correct, clean or replace.*1 : The drive belt should be replaced when cracks occur or tension is reduced excessively.
*2 : Requires API SN PLUS (or above) grade engine oil. If a lower grade engine oil is used, then the engine oil and engine oil filter
must be replaced at every 5,000 miles (8,000 km) or 6 months as indicated for severe maintenance condition.
*3 : If TOP TIER Detergent Gasoline is not available, one bottle of additive is recommended. Additives are available from your
authorized HYUNDAI dealer along with information on how to use them. Do not mix other additives.

08
8-11
Maintenance Under Severe Usage Conditions (Smartstream G1.6 T-GDi)
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 or change.
I : Inspect and if necessary, adjust, correct, clean or replace.
MAINTENANCE ITEMMAINTENANCE
OPERATION MAINTENANCE
INTERVALS DRIVING
CONDITION
Engine oil and filter *
1R Every 5,000 miles or
6 months A, B, C, D, E, F,
G, H, I, J, K, L
Air cleaner filter RMore frequently C, E
Spark plugs RMore frequently A, B, H, I, K
Automatic transmission fluid R Every 60,000 miles A, C, E, F, G, I
Front brake disc/pads, calipers I More frequently C, D, G, H
Rear brake shoes or disc/pads IMore frequently C, D, G, F
Parking brake IMore frequently C, D, G, H
Steering gear box, linkage &
boots/ lower arm ball joint,
upper arm ball joint I
More frequently C, D, E, F, G,
H, I
Suspension mounting bolts IMore frequently C, D, E, F, G,
H, I
Drive shafts and boots IEvery 3,000 miles or
6 months C, D, E, F, G,
H, I
Climate control air filter
(for evaporator and blower unit) R
More frequently C, E
*1 : Requires grade engine oil. If a lower grade
engine oil (mineral oil including Semi-synthetic) is used, then the engine oil and engine
oil filter must be replaced as indicated for severe maintenance condition.
Severe Driving Conditions
A. Repeatedly driving short distances
of less than 5 miles (8 km) in normal
temperature or less than 10 miles (16
km) in freezing temperature
B.

Ext
ensive engine idling or low speed
driving for long distances
C.
Driving on r

ough, dusty, muddy,
unpaved, graveled or salt- spread
roads
D.
Driving in ar

eas using salt or other
corrosive materials or in very cold
weather
E.

Driving in sandy ar
eas F.
Driving in hea

vy traffic area over 90°F
(32°C)
G. Driving on uphill, do wnhill, or
mountain road
H.

T
owing a Trailer, or using a camper, or
roof rack
I.

Driving as a pa
trol car, taxi, other
commercial use or vehicle towing
J.
Driving o

ver 106 mph (170 km/h)
K. Frequently driving in stop-and-go conditions
L.

E
ngine oil usage which is not
recommended (semi-synthetic, mineral
type, lower grade spec, etc.)

Maintenance
8-12
Normal Maintenance Schedule (Smartstream G2.5 GDi)
MAINTENANCE INTERVALS
MAINTENANCE
ITEM Months 12 24 36 48 60 72 84 96 108 120 132 144 156
Miles×1,000 8 16 24 32 40 48 56 64 72 80 88 96 104 Km×1,000 13 26 39 52 65 78 91 104 117 130 143 156 169
Drive belts
*1
At first, inspect at 48,000 miles (78,000 km) or 72 months.
Thereafter, inspect every 8,000 miles (13,000 km) or 12 months
Engine oil and engine oil filter
*2
R R R R R R R R R R R R R
Fuel additives
*3
Add fuel additives every 8,000 miles (13,000 km) or 12 months
Air cleaner filter I I R I I R I I R I I R I
Air intake hose I I I I I I I I I I I I I
Spark plugs Replace every 96,000 miles
Rotate tires Rotate tires every 8,000 miles (13,000 km)
Climate control air filter R R R R R R
Vacuum hose I I I I I I I I I I I I I
Engine coolant At first, replace at 120,000 miles or 120 months.
Thereafter, replace every 30,000 miles or 24 months
R: Replace or change.
I : Inspect and if necessary, adjust, correct, clean or replace.*1 : The drive belt should be replaced when cracks occur or tension is reduced excessively.
*2 : Requires API SN PLUS (or above) grade engine oil. If a lower grade engine oil is used, then the engine oil and engine oil filter
must be replaced at every 5,000 miles (8,000 km) or 6 months as indicated for severe maintenance condition.
*3 : If TOP TIER Detergent Gasoline is not available, one bottle of additive is recommended. Additives are available from your
authorized HYUNDAI dealer along with information on how to use them. Do not mix other additives.

08
8-15
Maintenance Under Severe Usage Conditions (Smartstream G2.5 GDi)
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 or change.
I : Inspect and if necessary, adjust, correct, clean or replace.
MAINTENANCE ITEMMAINTENANCE
OPERATION MAINTENANCE
INTERVALS DRIVING
CONDITION
Engine oil and filter *
1R Every 5,000 miles or
6 months A, B, C, D, E, F,
G, H, I, J, K, L
Air cleaner filter RMore frequently C, E
Spark plugs RMore frequently A, B, F, G, H, I, K
Automatic transmission fluid R Every 60,000 miles A, C, E, F, G, I
Front brake disc/pads, calipers I More frequently C, D, G, H
Rear brake shoes or disc/pads I More frequently C, D, G, F
Parking brake IMore frequently C, D, G, H
Steering gear box, linkage &
boots/ lower arm ball joint,
upper arm ball joint I
More frequently C, D, E, F, G,
H, I
Suspension mounting bolts IMore frequently C, D, E, F, G,
H, I
Drive shafts and boots IEvery 3,750 miles or
6 months C, D, E, F, G,
H, I
Climate control air filter
(for evaporator and blower unit) R
More frequently C, E
*1 : Requires grade engine oil. If a lower grade
engine oil (mineral oil including Semi-synthetic) is used, then the engine oil and
engine oil filter must be replaced as indicated for severe maintenance condition.
Severe Driving Conditions
A. Repeatedly driving short distances
of less than 5 miles (8 km) in normal
temperature or less than 10 miles (16
km) in freezing temperature
B.

Ext
ensive engine idling or low speed
driving for long distances
C.
Driving on r

ough, dusty, muddy,
unpaved, graveled or salt- spread
roads
D.
Driving in ar

eas using salt or other
corrosive materials or in very cold
weather
E.

Driving in sandy ar
eas F.
Driving in hea

vy traffic area over 90°F
(32°C)
G. Driving on uphill, do wnhill, or
mountain road
H.

T
owing a Trailer, or using a camper, or
roof rack
I.

Driving as a pa
trol car, taxi, other
commercial use or vehicle towing
J.
Driving o

ver 106 mph (170 km/h)
K. Frequently driving in stop-and-go conditions
L.

E
ngine oil usage which is not
recommended (semi-synthetic, mineral
type, lower grade spec, etc.)

Maintenance
8-16
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.
Drive Belts
Inspect all drive belts for evidence
of cuts, cracks, excessive wear or oil
saturation and replace if necessary. Drive
belts should be checked periodically
for proper tension and adjusted as
necessary.
Fuel Filter
A clogged-up fuel filter may limit the
vehicle driving speed, damage the
emission system, and cause the hard
starting. When a considerable amount
of foreign substances are accumulated
in the fuel tank, the fuel filter should be
replaced.
Upon installing a new fuel filter, operate
the engine for several minutes, and
check the connections for any leakages.
Fuel filters should be installed by an
authorized HYUNDAI dealer.
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.
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.
Explanation of SChEdulEd maintEnanCE itEmS