In a 2005 Kia Sorento with a 2.5-liter engine, it is best to use synthetic 5w30 oil, and in a 2005 Kia Sorento with a 3.5-liter engine, it is best to use semi synthetic 10w40 oil. To determine when to change the oil in this vehicle, the car owner should consult the owner's manual. The recommendation usually falls between 5,000 and 7,500 miles.
Certain factors may make it necessary to change the oil in a vehicle more often. These include frequent driving in extreme cold and extreme heat, hard driving, frequent driving on dusty roads and commonly driving in stop and go traffic.