2018 Hyundai Ioniq Hybrid radiator cap

3-40
3. Pull the fuel filler door (1) out to
fully open.
4. To remove the fuel tank cap (2),
turn it counterclockwise. You may
hear a hissing noise as the pres-
sure inside the tank equalizes.
5. Place the cap on the fuel filler door.
Information
If the fuel filler door does not open
because ice has formed around it, tap
lightly or push on the door to break
the ice and release the door. Do not
pry on the door. If necessary, spray
around the door with an approved de-
icer fluid (do not use radiator anti-
freeze) or move the vehicle to a warm
place and allow the ice to melt.
Closing the fuel filler door
1. To install the fuel tank cap, turn it
clockwise until it “clicks” one time.
2. Close the fuel filler door until it is
latched securely.
i
Convenient features of your vehicle
Gasoline is highly flammable
and explosive. Failure to follow
these guidelines may result in
SERIOUS INJURY or DEATH:
•Read and follow all warnings
posted at the gas station.
•Before refueling, note the
location of the Emergency
Gasoline Shut-Off, if available,
at the gas station.
•Before touching the fuel noz-
zle, you should eliminate the
potential build-up of static
electricity by touching a metal
part of the vehicle, a safe dis-
tance away from the fuel filler
neck, nozzle, or other gas
source, with your bare hand.
(Continued)
WARNING
OAE046025
(Continued)
•Do not use cellular phones
while refueling. Electric cur-
rent and/or electronic interfer-
ence from cellular phones can
potentially ignite fuel vapors
and cause a fire.
•Do not get back into a vehicle
once you have begun refuel-
ing. You can generate a build-
up of static electricity by touch-
ing, rubbing or sliding against
any item or fabric capable of
producing static electricity.
Static electricity discharge can
ignite fuel vapors causing a
fire. If you must re-enter the
vehicle, you should once again
eliminate potentially danger-
ous static electricity discharge
by touching a metal part of the
vehicle, away from the fuel filler
neck, nozzle or other gasoline
source, with your bare hand.
(Continued)

6-13
What to do in an emergency
6
7. If you cannot find the cause of the
overheating, wait until the engine
temperature has returned to nor-
mal. Then, if coolant has been
lost, carefully add coolant to the
reservoir to bring the fluid level in
the reservoir up to the halfway
mark.
8. Proceed with caution, keeping
alert for further signs of overheat-
ing. If overheating happens again,
we recommend that you call an
authorized HYUNDAI dealer for
assistance.
•Serious loss of coolant indi-
cates a leak in the cooling
system and we recommend
the system be checked by an
authorized HYUNDAI dealer.
•When the engine overheats
from low engine coolant, sud-
denly adding engine coolant
may cause cracks in the
engine. To prevent damage,
add engine coolant slowly in
small quantities.
CAUTION
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 pres-
sure, causing serious injury.
Turn the hybrid system off and
wait until the engine cools down.
Use extreme care when remov-
ing the engine coolant 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 system. When you are
sure all the pressure has been
released, press down on the cap,
using a thick towel, and continue
turning counterclockwise to
remove it.
WARNING

7-21
7
Maintenance
EXPLANATION OF SCHEDULED MAINTENANCE ITEMS
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 con-
ditions, 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 lines, fuel hoses and con-
nections
Check the fuel lines, fuel hoses and
connections for leakage and dam-
age. We recommend an authorized
HYUNDAI dealer replace any dam-
aged 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 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.
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.

7-26
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.
i
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 pres-
sure, causing serious injury.
Turn the hybrid system off and
wait until the engine cools down.
Use extreme care when remov-
ing the engine coolant 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 system. When you are
sure all the pressure has been
released, press down on the cap,
using a thick towel, and continue
turning counterclockwise to
remove it.
WARNING
OAE076006
OAE076007
■Engine coolant cap
■Inverter coolant cap

8-6
Specifications & Consumer information
RECOMMENDED LUBRICANTS AND CAPACITIES
To help achieve proper engine and powertrain performance and durability, use only lubricants of the proper quality.
The correct lubricants also help promote engine efficiency that results in improved fuel economy.
These lubricants and fluids are recommended for use in your vehicle.
Lubricant Volume Classification
Engine oil *
1*2Recommends
(drain and refill)3.8 l
(4.0 US qt.)5W-30
ACEA A5/B5
Dual clutch transmission fluid1.6 ~ 1.7 l
(1.69 ~ 1.79 US qt.)SAE 70W, API GL-4
HK SYN DCTF 70W (SK)
SPIRAX S6 GHME 70W DCTF (H.K.SHELL)
GS DCTF HD 70W (GS CALTEX)
Engine clutch actuator fluid100 ± 20 cc
(0.105 ± 0.021 US qt.)DOT 3
Engine coolant6.7 l(7.07 US qt.)
Mixture of antifreeze and water
(Phosphate-based Ethylene glycol coolant for aluminum radiator)
Inverter coolant3.2 l(3.38 US qt.)
Brake fluid0.7~0.8 l
(0.74~0.85 US qt.)FMVSS116 DOT-3 or DOT-4
FuelHybrid vehicle45 l(47.5 US qt.)
Refer to “Fuel requirements” in the Introduction chapter.
Plug-in hybrid vehicle43 l(45.4 US qt.)
*1: Refer to the recommended SAE viscosity numbers on the next page.
*2: Engine oils labeled Energy Conserving Oil are now available. Along with other additional benefits, they contribute to fuel economy by reducing
the amount of fuel necessary to overcome engine friction. Often, these improvements are difficult to measure in everyday driving, but in a year’s
time, they can offer significant cost and energy savings.