På kiaownersclub står følgende:
I don't know what year you have but you should be aware that up until at least 2005 these cars suffered from failure of the oil pump. Have your guy take the pump off and check the integrity of the driven gear and the internal trochoidal pump mechanism.
Better yet check with Kia themselves to see if there are any recalls on your car. For later models there was also an oil pump strainer issue. Here is a quote from an on line review of these cars
"Oil pressure: make sure the oil
pressure warning light goes out when you start the engine. Some cars
were fitted with a faulty oil-pump strainer, which should already have
been renewed. If it hasn't, the tell-tale sign could stay lit."