The Hyundai Theta (G4KC) is a gasoline 4-cylinder automobile engine family. The third all-aluminum engine of Hyundai Motor Company debuted in the fourth-generation Hyundai Sonata sedan (codenamed NF), which was unveiled in August 2004 in South Korea. Hyundai Motor Manufacturing Alabama (HMMA) built a Theta II engine shop on the grounds of their Montgomery, Alabama automobile factory. The shop builds only the Theta II engine for both the Hyundai plant and the new Kia Plant in West Point, GA.