See also:

Rear differential (4WD)
Checking or changing rear differential fluid Have rear differential fluid checked or changed by an Authorized Kia Dealer according to the Maintenance Schedule at the beginning of this section. ...

Fuel requirements
Gasoline engine (unleaded) Your new Kia vehicle is designed to use only unleaded fuel with a minimum Octane Rating of 87 Anti-Knock Index (AKI). NOTICE NEVER USE LEADED FUEL. The use of leaded ...

Convenience
The Kia Rio's fuel tank will need to be replenished more often than the unit in the average sedan. ...