I do not have the owner's manual for my Optima and do not know what is the best oil weight for my car?
Motor Oil on 2004 Kia Optima
Kia call for SG or SH spec oil. They call for 10/30W for ambient temps between 0 to 90 degrees and 10/40 for temps between 0 and 120 degrees. If your car has high mileage I would use 10/40. With oil filter change you need 5 quarts total.
2 more answers
take it to your local dealer they have everything you need to know.....5w20....???????
i do have the manual mail me firstname.lastname@example.org