Honda Civic Owner's Manual page 231

Make sure the API Certification Seal
says ''For Gasoline Engines.''
The oil viscosity or weight is
provided on the container's label.
All models except U.S. Si:
Honda Motor Oil is the preferred
5W-20 lubricant for your vehicle.
5W-20 oil is formulated for year-
round protection of your vehicle, to
improve cold weather starting and
fuel economy.
Ambient Temperature
U.S. Si model:
Ambient Temperature
An oil with a viscosity of 5W-30 is
preferred for improved fuel economy
and year-round protection in your
vehicle. You may use a 10W-30 oil if
the temperature in your area never
goes below 20°F ( 7°C).
Adding Engine Oil
Synthetic Oil
You may use a synthetic motor oil if
it meets the same requirements
given for a conventional motor oil: it
displays the API certification seal,
and it is the proper weight. You must
follow the oil and filter change
intervals shown on the information
display.
Engine Oil Additives
Your vehicle does not require any oil
additives. Additives may adversely
affect the engine or transmission
performance and durability.
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