Hello, your fluid may leak predominantly under pressure. Have a local repair facility perform a physical inspection to determine what is occurring. Here are some shops near you: http://repairpal.com/kia-within-10-miles-of-tucson-arizona-85711
RepairPal Certified shops can diagnose and repair your 1999 Kia Sephia. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.