The Jaguar AJ-8 is a compact DOHC V8 piston engine used in many Jaguar vehicles. It was the fourth new engine type in the history of the company. In 1997 it replaced both designs previously available on Jaguar cars: the straight-6 Jaguar AJ6 engine (or rather its AJ16 variant), and the Jaguar V12 engine. It remained the only engine type available on Jaguar until 1999 with the launch of the S-Type, when the Jaguar AJ-V6 engine was added to the list.