Hyundai Sonata Hybrid 2017 Owner's Manual page 473

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.
7-22
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 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
OLFH074006
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:
Mixture Percentage
Ambient
(volume)
Temperature
Antifreeze
-15°C (5°F) 35
-25°C (-13°F) 40
-35°C (-31°F) 50
-45°C (-49°F) 60
i
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
-35°C (-31°F) and higher.
Water
65
60
50
40