The 2014 Kia Rio GDI engine is a terrible design. The fuel injectors being below the valves cause heavy carbon build up on the valves. I spent $100 on different intake valve cleaners and used a bore scope camera to make sure the valves were clean. I do all of my own repairs on my cars but I'm not ready to tackle rebuilding the engine. It started out only adding 1 quart of oil every 1k miles. Then I went from 0-20 oil to 5-20 and now am at 10-30 to try to get the "blow by" to lessen. Now I'm adding 2 quarts every 1k miles. And its smoking like a chimney. I can't drive with the window down because of the oil smell. It really sucks because the car is less than 10 years old and is in immaculate condition. I see there is a class action lawsuit against Hyundai for this exact problem. I have to find out to get my name on that list.