For the 1959 Formula One season the works cars were finally upgraded to the full 2.5-litre specification, and mechanical upgrades had been made to improve reliability. In addition to the works team, Lotus 16s had also been sold to a number of privateer entrants. As the season progressed the works cars were gradually developed still further, and their qualifying times began to fall. Reliability was still a major issue, however, and too often the cars failed to complete a full race distance. Although regular works driver Hill failed to finish even a single race during the season, his team-mate Innes Ireland's car held together long enough to take five World Championship points, with fourth place in the Dutch Grand Prix and fifth in the season finale in the United States.