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Audi 100: C3 and C4 generations, engines and trims
The Audi 100 is a premium mid-size Audi car, produced from 1968 to 1994 and serving as the direct predecessor to the Audi A6. In Lithuania, you'll most commonly encounter the C3 and C4 generations, valued for their spaciousness, durability, and galvanised bodies. We'll explore what sets them apart, which engines are most common, and what to check when buying a car of this vintage.
Audi 100 in brief
The Audi 100 was produced in four generations: C1 (1968–1976), C2 (1976–1982), C3 (1982–1991), and C4 (1990–1994). In 1994, the refreshed C4 was rebranded as the Audi A6. Today, the used market is almost exclusively C3 and C4 models, with earlier generations typically snapped up by collectors.
The Audi 100 was offered in sedan and estate — Avant — bodystyles, with front-wheel drive or the permanent four-wheel-drive system quattro. It's a spacious, comfortable car with a straightforward design, long appreciated in Lithuania for its durability and ease of maintenance. However, even the youngest examples are over 30 years old, so the condition of each car can vary greatly.
C3 and C4 — what's the difference
The C3 (1982–1991) stood out with its sleek body — its drag coefficient was around 0.30, remarkably low for a production car of the time. Later C3 models received fully galvanised bodies, and the 1988 model was refreshed. This generation also spawned the more luxurious Audi 200.
C4 (1990–1994) — a significantly updated C3: different front and rear, a more modern interior, and better safety. This time around, V6 petrol engines and the sporty S4 version were introduced, while the 2.5 TDI became the most popular diesel.
For everyday driving, the C4 generation is more practical — it's newer and often in better condition. The C3 appeals to those who like its classic design, or those looking for the simplest and cheapest car.
Engines and gearboxes
In the C3 generation, four and five-cylinder 1.8–2.3 petrol engines are most commonly found, along with five-cylinder diesels and turbodiesels. Since 1989, the 2.5 TDI (around 120 HP) has been offered — one of the first light cars with a turbocharged diesel engine and direct injection.
In the C4 generation, the most common engines are the 2.0 (usually around 100–115 HP) and five-cylinder 2.3 (around 133 HP) petrols, 2.6 and 2.8 V6 (around 150 and 174 HP) engines, and five-cylinder 2.4 D and 2.5 TDI (around 115 HP) diesels. The sporty S4 featured a five-cylinder 2.2 turbocharged engine (around 230 HP), later joined by a 4.2 V8.
Most commonly found is a five-speed manual gearbox, less often an automatic. Quattro versions have permanent four-wheel drive, which is particularly valued in winter.
What to check when buying a used Audi 100
An uncared-for body after several decades and repairs can rust — usually sills, wheel arches, door bottoms, and boot floors. Not all early C3 cars have a fully galvanized body, so it's worth inspecting them particularly carefully. Ask if the body hasn't been welded.
In a car of this age, you'll often need to replace rubber parts, hoses, suspension bushes, and steering rack mounts. Check if the engine doesn't leak oil and runs smoothly when cold, and in the case of the 2.5 TDI — if it starts easily and doesn't smoke. The central locking is pneumatically operated, so issues with its pump and pipes aren't uncommon.
Request registration and MOT documents, and compare VIN numbers. Some body and interior parts can be hard to find, so it's worth choosing the most complete and original car.
Versions
Audi 100 trim levels varied by market and year (e.g., C3 was sometimes CC or CD), so we list the most commonly encountered body, engine, and gearbox versions.
Audi 100 sedanas
C3 and C4The most common version is a spacious four-door saloon with a large boot.
- Mostly 2.0–2.3 petrol engines or five-cylinder diesels
- Simple, easily serviced technology
- Spacious rear seats
Audi 100 Avant
C3 and C4Estate — the most practical version for families and loads.
- Large boot, C3 had a sloping rear end
- Often — roof rails
- Many of the same engines as the saloon
quattro
C3 and C4Permanent four-wheel drive — great grip in winter and on poor roads.
- Four-wheel drive
- Often — with more powerful engines
- Higher fuel consumption and a more complex transmission
2.5 TDI
C3 (from 1989) and C4Five-cylinder turbodiesel — the most economical and widely praised version.
- Around 115–120 HP and a hefty torque
- Low fuel consumption for a car of this size
- A well-maintained engine will run for a very long time
S4
C4 (1991–1994)Sporty version with quattro four-wheel drive, renamed S6 in 1994.
- Five-cylinder 2.2 turbo (around 230 HP) or 4.2 V8
- Quattro four-wheel drive
- Rare, prized by enthusiasts and collectors
Comparison of the most common versions
| Sedanas | Avant | quattro | 2.5 TDI | |
|---|---|---|---|---|
| Who it suits | Ideal for daily driving | Family-friendly and spacious | Built for winter and rough roads | High-mileage drivers |
| Hatchback | Sedanas | Estate | Saloon or Notchback | Saloon or Notchback |
| Gearbox | Front-wheel drive | Front-wheel drive | Four-wheel drive | Front-wheel drive |
| Engine (most common) | 2.0–2.3, 2.4 D | 2.0–2.6, 2.5 TDI | 2.3–2.8 | 2.5 TDI |
| Price in the used market (relatively) | € | € | €€ | €€ |
Most buyers' best bet is the C4 sedan or Avant with a 2.3 or 2.5 TDI engine. Quattro is worth choosing if traction in winter is crucial, but with an older car, the condition of the body and mechanics is still the most important.
Pros
- Spacious interior and large boot
- Later C3 and C4 models have a galvanised body
- Simple, easily serviced technology
- Reliable five-cylinder petrol engines and the 2.5 TDI diesel
Cons
- Age means rust and worn-out parts
- High fuel consumption for older petrol engines
- It's getting harder to find certain interior and body parts
Frequently asked questions
What's the difference between the Audi 100 and Audi A6?
The 1994 facelifted Audi 100 C4 was renamed the Audi A6 (C4). The technology remained essentially the same, but the A6 got a different front and rear, a refreshed interior and some new engines.
Which generation of Audi 100 is best to buy?
For daily driving, the C4 generation is usually the go-to choice — it's newer, safer and offers more engine options. The C3 is worth considering if you like its design and can find a well-maintained, non-rusty example.
Which Audi 100 engine is the most reliable?
The five-cylinder 2.3 petrol and 2.5 TDI diesel are often praised — they're simple and, if well-maintained, will cover many miles. However, with an older car, the condition and service history of the specific engine is more important than its type.
Can the Audi 100 be registered as a historic vehicle?
Cars older than 30 years that meet the criteria for historic vehicles (originality and condition) can be registered as such. All Audi 100s from the C3 and C4 generations have now reached this milestone.
Updated 2026-10-09 · Trim levels and equipment vary by market and model year — check the equipment of the specific car. · Translated automatically
