The Ford Sierra RS Cosworth Supplement to 'Your Sierra Owner Literature Feb 1986 1st Year' is a workshop manual published by Ford in the United Kingdom. Specifically designed for owners of the Ford Sierra Cosworth model, this paper-based manual provides detailed information on how to service and repair the vehicle. With a focus on the 1986 year, this supplement serves as a valuable resource for those looking to maintain or restore their classic Ford Sierra Cosworth. It is a must-have for enthusiasts and collectors of this specific model.