The International S series was built from 1977 to 2001 and replaced both the medium-duty Loadstar and the heavy-duty Fleetstar with a single range. It was the last complete product line designed while International Harvester still existed, and it survived the company’s transformation into Navistar.
International S series at a glance
| Maker | International Harvester, later Navistar International |
|---|---|
| Production | 1977–2001 |
| Replaces | International Loadstar and International Fleetstar |
| Position in range | below the Transtar and Paystar Class 8 conventionals |
| Variants | straight truck, semi-tractor, vocational and severe-service |
| Bodies | crew cab, cutaway cab, cowled chassis, stripped chassis for buses |
| Drive layouts | 4×2, 4×4 and 6×6; single or tandem rear axles |
| Cab | model-specific, wider than the Loadstar’s, with flat glass throughout |
| Bonnet | tilting glassfibre on every model |
| Diesels only | from 1986–1987, a first for a medium-duty line |
| Second generation | ‘Thousand Series’, from 1989 |
| Last variants | severe-service to 2003, bus chassis to 2004 |
Written from the English Wikipedia article on the S series, a single source.
History of the International S series
The S series was unveiled in April 1977 at an event at the New Orleans Superdome, and its purpose was consolidation: the medium-duty Loadstar and the heavy-duty Fleetstar became one family. The first models were the heavier 2200, 2500 and 2600, with gross vehicle weight ratings of 28,000 to 45,000 lb, which replaced the Fleetstar; the lighter models that replaced the Loadstar went on sale in the summer of 1978. The full line-up ran to 21 models with a high degree of parts interchangeability, which cut the number of parts used by 30 per cent.
The cab was new and specific to the S series. After International’s pickup line ended in 1975 there was no reason to keep using the pickup-derived cab that the Loadstar had inherited from the 1957 A series, so the S series received a cab that was more upright and much wider than before. To keep maintenance costs down, every window — including the windscreen — was flat glass, and every truck had a tilting glassfibre bonnet of the kind introduced on the Loadstar in 1972. The design was produced through the 1980s largely unchanged.
The model range spread across the weight classes. The S1600, S1700, S1800 and S1900 of 1979 replaced the Loadstar, with single or tandem rear axles, 4×4 and 6×6 options and petrol or diesel engines; the S1800 and S1900 were sold as both tractors and straight trucks, and the S1700 and S1800 formed the basis of International’s school-bus chassis. The S2100 and S2200 of 1978 replaced the Fleetstar and were joined by the severe-service S2500 and S2600, slotted below the Paystar 5000. To fit larger diesel engines under a standard bonnet the S2200 received a widened cab with a two-piece windscreen, and in 1982 the S2300 arrived with Cummins powertrains in place of International’s own diesels.
Two landmarks followed. In 1987, as the company became Navistar International, the trucks received new badging — a red Navistar diamond on the grille and on the steering wheel — and International became the first truck manufacturer to offer a medium-duty line powered exclusively by diesel engines. In 1989 the S series was substantially redesigned and split into three model families under the “Thousand Series” naming, keeping the 1977 cab structure but with a lower bonnet line, closer-fitting wings, halogen headlamps and a new interior with an electronic instrument cluster. The second generation changed little afterwards: the instrument panel was revised in 1992 and the interior in 1995, and production continued until 2001, when International moved to its NGV architecture. Severe-service and bus-chassis variants carried on to 2003 and 2004.
Design and features
- One range for two: the Loadstar and Fleetstar consolidated into a single line.
- New cab: wider and more upright, with flat glass in every window.
- Tilting bonnet: glassfibre on all models, for access to the engine.
- Standardisation: 21 models with parts interchangeability that cut part numbers by 30 per cent.
- Diesel only: from 1987, a first for a medium-duty range.
International S series versions
- S1600 to S1900 (1979): the Loadstar replacements.
- S2100, S2200 and S2300: the Fleetstar replacements.
- S2500 and S2600: severe-service models.
- Thousand Series (1989–2001): second generation with a redesigned front and interior.
- Bus and severe-service chassis: built until 2003–2004.
The S series replaced both the Loadstar and the Fleetstar, and it was the successor to the heavy R series line. More trucks are in the collection.
Sources
- International S series, English Wikipedia: launch, cab, models, Navistar changes, generations
