International S series (bus chassis)

The bus chassis variant of the International S series is a cowled bus chassis (conventional style) that was produced by International Harvester (later Navistar International) from 1979 to 2001. Produced primarily for school bus applications, the chassis was also produced for other applications, including commercial-use buses and cutaway-cab buses. In addition, the cowled chassis formed the basis for front-engine and rear-engine stripped chassis produced for bus applications.

Designed as a replacement for the International Loadstar bus chassis, the S-series bus chassis was produced in two distinct generations. Matching the development of the International S series, during 1989, the model line underwent a major update, becoming the International 3800. The 3800 was also made in a truck variant. In 2004, the International 3800 ended production, replaced by the International 3300 (a cowled-chassis version of the International 4300/DuraStar). In production for over 25 years, the S-series bus chassis was the longest-lived model line ever produced by International and the final Navistar product line developed by International Harvester.