M10 four-cylinders
Carburetted and injected 1.6–2.0-litre versions formed the core range: 315, 316, 318/318i and early 320/320i derivatives.
3 Series (E21) — Two-door Sedan
1975–1983
Editorially reviewedReviewed 2026-08-10; market and model-year scope is stated in the record sources.
- Internal code
- E21
- Production
- June 1975 – December 1983
- Body style
- 2-door sedan · 5 seats
- Platform
- longitudinal engine · rear-wheel drive · independent suspension
Body variants
3 Series → E21 → Two-door Sedan
3 Series E21: history, design and engineering
How this generation came about, what made it different and how the selected two-door sedan fits into the family.
The E21 created the 3 Series as BMW still understands it today: a compact car with a longitudinal engine, rear-wheel drive and a cabin organised around the driver. It replaced the 02 Series in 1975, kept the crisp three-box proportions of its predecessor and gave BMW's smallest saloon a distinct model identity.
Its story is also one of steady growth. Early four-cylinder cars established the affordable end of the range, while the later six-cylinder 320/6 and 323i brought the smoothness and performance that would become closely associated with the 3 Series. The body choice was simple, but the engine range was not.
BMW itself manufactured E21 only as a two-door sedan. Baur TopCabriolet cars were coachbuilt conversions distributed through BMW channels, while racing cars and tuners created further shapes and specifications; those vehicles belong in derivative records rather than in the factory body tree. The 1977 arrival of M20 six-cylinder models is the main technical dividing line inside the production range.
06/1975–12/1983production
1BMW factory body
M10 / M20engine families
RWDdriven wheels
2 563 mmwheelbase
315–323icore range
Two-door Sedan: dimensions and packaging
Dimensions can change with body, market and model year, so this page keeps them tied to the exact factory branch.
Length4,355 mm
Width1,610 mm
Height1,380 mm
Wheelbase2,563 mm
Luggage≈ 400 L
Fuel tank58 L
Seats5
Doors2-door sedan · 5 seats
| Body | Code | Production | Doors / seats | Length | Luggage |
|---|---|---|---|---|---|
| Two-door Sedan | E21 | 1975–1983 | 2-door sedan · 5 seats / 5 | 4,355 mm | ≈ 400 L |
Engines and powertrains
The generation could span very different engines and drivetrains. The table keeps output, gearbox, market and production period together.
Factory modification matrix
Documented two-door sedan applications; output and availability remain market- and model-year-specific.
| Model | Years | Engine | Output | Transmission | Drive | Market | Source |
|---|---|---|---|---|---|---|---|
| 315 | 1981–1983 | M10B16 | 75 PS | 4MT | RWD | Europe | BMW 3 Series Sedan (E21) |
| 316 | 1975–1983 | M10B16 / M10B18 | 90 PS | 4MT / 5MT / 3AT | RWD | Europe | BMW 3 Series Sedan (E21) |
| 318 | 1975–1980 | M10B18 | 98 PS | 4MT / 5MT / 3AT | RWD | Europe | BMW 3 Series Sedan (E21) |
| 318i | 1980–1983 | M10B18 | 105 PS | 5MT / 3AT | RWD | Global range | BMW 3 Series Sedan (E21) |
| 320 / 320i | 1975–1977 | M10B20 | 109–125 PS | 4MT / 5MT / 3AT | RWD | Global range | BMW 3 Series Sedan (E21) |
| 320/6 | 1977–1982 | M20B20 | 122 PS | 4MT / 5MT / 3AT | RWD | Europe | BMW 3 Series Sedan (E21) |
| 323i | 1977–1982 | M20B23 | 143 PS | 5MT / 3AT | RWD | Global range | BMW 3 Series Sedan (E21) |
| 320i (US) | 1977–1983 | M10B20 / M10B18 | 101–110 hp | 4MT / 5MT / 3AT | RWD | North America | BMW 3 Series Sedan (E21) |
M20 six-cylinders
From 1977 the 320/6 and 323i used compact inline-sixes; the fuel-injected 323i became the flagship series-production E21.
Markets and emissions
Output, fuel system and emissions hardware varied by country and year; the sales badge alone is insufficient for parts identification.
How power reaches the road
Gearboxes, driven wheels and final-drive hardware changed with engine, market and production date.
Transmissions
Gearbox type and unit code follow engine, market and production date. Gear count alone does not identify the transmission.
Driven wheels
Catalog architecture: longitudinal layout · rear-wheel drive. All-wheel-drive availability and hardware remain derivative-specific.
Final drive
Ratio, differential type and electronic control belong to the exact derivative and can differ on performance models.
What changed underneath
Suspension, brakes, safety systems and electronics evolved across the range, even when cars shared the same basic architecture.
Body & suspension
- Mounting points and geometry follow the body branch
- Springs and dampers follow axle load and chassis package
- Wheels and permitted loads follow the factory label
Brakes & steering
- Brake size follows engine and equipment
- Assistance type and steering ratio can change
- ABS/DSC generation follows model year
Passive safety
- Airbag count varies by market and year
- SRS parts are VIN-specific
- Structural repairs require factory procedures
Electronics
- Vehicle-bus generations changed during production
- Control-unit software levels must remain compatible
- Retrofits are recorded separately from factory equipment
How the generation evolved
The important launches, additions and updates did not always happen at the same time for every body or market.
Launch
The 316, 318, 320 and 320i two-door sedans replace the BMW 02 family.
Six cylinders
The 320/6 and 323i join the range, with chassis, brake and equipment changes on upper derivatives.
Range revisions
Technical and visual revisions arrive; the 315 becomes the late-cycle entry model.
Production ends
BMW E21 production ends in December; Baur coachbuilt conversions remain a separately identified derivative.
The versions that stood apart
Performance models, option packages and regional editions may look related, but their engineering and production identity can be very different.
Series-production range
E21The principal factory derivatives, separated by engine, driven wheels, market and equipment level.
Performance derivatives
M / SportAppearance package, sports chassis package and standalone M model are different records and are not merged by visual similarity.
Regional editions
MarketLimited editions and local specifications are added only when a factory document, edition number or unambiguous market specification is available.
Inside the car
Cabin technology and standard equipment changed by country and year; a build sheet remains the best guide to one individual car.
Cabin & comfort
- Trim and seats follow option codes
- Climate systems vary by market
- Audio and navigation changed by model year
Lighting & assistance
- Lamp technology and modules follow production date
- Driver assistance cannot be inferred from buttons alone
- Regional rules affect lighting and warnings
What to check today
A practical starting point for inspecting and maintaining a car from this generation — not a diagnosis of an individual example.
Body
- Sills, jacking points and suspension mounts
- Arches, door bottoms and luggage compartment
- Historic repairs and blocked drains
Fuel and cooling
- Fuel hoses and mechanical-injection condition
- Radiator, pump, thermostat and hoses
- Carburettor synchronisation where fitted
Running gear
- Steering and front-arm play
- Rear semi-trailing-arm bushes
- Brake and differential specification
| Item | Interval / trigger | Catalog note |
|---|---|---|
| Oil and filter | yearly / mileage-based | Viscosity and approval follow engine and climate. |
| Ignition and valve clearances | M10/M20 factory interval | Check clearances, plugs, cap and rotor. |
| Fuel hoses | inspect at every service | Age-hardened hose should be renewed as a fuel-compatible set. |
| Brake fluid | every 2 years | Inspect cylinders, flexible hoses and hard lines at the same time. |
How to identify the exact car
The badge and registration year tell only part of the story; production date, body code, engine and factory options complete it.
- VIN
- Identifies model, plant and production branch and keys the parts catalog and factory equipment record.
- Production date
- More useful than first-registration year when choosing parts and locating technical revisions.
- Type code
- Refines engine, body, market and transmission combination.
- Option codes
- Confirm factory equipment; later retrofits are recorded separately.
- Unit number
- Supports engine or gearbox originality checks and component applicability.
Where the information comes from
The story is mapped through English Wikipedia and its bibliography, then important dates and technical claims are checked against BMW material.
- 01BMW 3 Series (E21)Wikipedia contributors
English-language secondary overview of the generation, body programme, powertrains and production chronology; key claims are cross-checked against the factory sources below.
- 02BMW 3 Series Sedan (E21)BMW Group Classic / BMW Group
Official body history, production dates and position within the model range.
- 03BMW 3 Series celebrates 50 yearsBMW Group Classic / BMW Group
Official body history, production dates and position within the model range.
Notes and limitations
- Tree years describe the worldwide generation lifecycle; individual market dates may be narrower.
- Exact dimensions, power, weight and emissions belong at body, engine, market and model-year level.
- Known-issue guidance is editorial context and never replaces inspection of the individual vehicle.
3 primary references · market differences documentedPhotography: André Freud, CC BY-SA 3.0 · Wikimedia Commons. Rights checked 2026-08-06; local 640 px and 1,280 px avif versions created; the complete source frame is retained without cropping.Updated 6 August 2026