See also: List of GM platforms.
| GM C platform (FWD) | |
| Aka: | C-Body |
| Manufacturer: | General Motors |
| Production: | 1985–1996 |
| Successor: | GM G platform |
| Class: | Full-size car |
| Layout: | Transverse FF layout |
| Body Style: | Two- and four-door sedan; extended wheelbase limousine. |
| Related: | GM H platform (FWD) GM K platform (FWD) |
| Vehicles: | Buick Electra Buick Park Avenue Cadillac De Ville Cadillac Fleetwood Cadillac Series 75 Cadillac Sixty Special Oldsmobile 98 |
GM C platform, also known as the C-Body, was a front wheel drive (FWD) automobile platform used by General Motors' Cadillac, Buick and Oldsmobile divisions for their full-sized automobiles from 1985 through 1996, sharing unibody construction, transverse engine configuration, rack and pinion steering and four-wheel independent suspension.
C-Bodies used, V6 or V8 engines, GM's TMH440 transaxle (initially), unibody construction - and all had been aerodynamically refined, with the Oldsmobile achieving a .383 drag coefficient.
GM's C platform and H platform were largely identical, sharing the same 110.8 in wheelbase, most bodywork, interior details, glass and engines. Manufacture began with the C platform in late 1983, first at two purpose-built plants, Wentzville Assembly and Orion Assembly - later moving to Lansing Car Assembly as well as Flint and Willow Run assembly plants.
Significantly shorter, narrower, lighter and more fuel-efficient than the platform they replaced, the C Platform vehicles were noted for having nearly the same key interior dimensions as their predecessors and a much more nearly flat passenger compartment floor[1] - albeit with thinner seats and dramatically less upper tumblehome, locating windshield as well as side glass closer to passengers.[1]
Introduced in early 1984, the models were marketed as the Oldsmobile Ninety-Eight (11th gen), Buick Electra (6th gen) and Cadillac Deville (6th gen) and Fleetwood (1985-90)..
Cadillac would later introduce C Body models with a 113.8 in wheelbase. Most C-body vehicles were ultimately replaced with cars on the related G, H, and K platform designations.
The Cadillac Series 75 limousine briefly made its return on this platform, stretched by 23.6" to a wheelbase of 134.4". Cadillac used the platform though 1993; Buick heavily revised the Electra, becoming the first generation Buick Park Avenue (1991-1996), while still using the C Platform; and Oldsmobile marketed C Platform derivatives through 1990, notably the Oldsmobile Touring Sedan.
| Years | Model | Next platform |
|---|---|---|
| 1985–1987 | Cadillac Series 75 | - |
| 1985–1992 | Cadillac Fleetwood | GM D platform |
| 1985–1993 | Cadillac De Ville (6th Generation) | GM K platform (FWD) |
| 1987–1993 | Cadillac Sixty Special | - |
| 1985–1990 | Buick Electra (6th Generation) | - |
| 1991–1996 | Buick Park Avenue | GM G platform (FWD) |
| 1985–1996 | Oldsmobile 98 (11th generation) | |
| 1987–1990 | Oldsmobile Touring Sedan (subsequent 98 trim levels used a succeeding platform) |
The H platform and C platform were largely identical, sharing the same 110.8 in wheelbase, most bodywork, interior details, glass and engines.
| Years | Model | Previous platform | Next platform | |
|---|---|---|---|---|
| 1986–1999 | Buick LeSabre | GM B platform | GM G platform | |
| 1986–1999 | Oldsmobile 88/LSS | GM B platform | Retired | |
| 1987–1999 | Pontiac Bonneville | GM G platform (RWD) | GM G platform (FWD) |