The Audi A4 (B6), produced between 2002 and 2005, represented a significant evolution for Audi’s popular compact executive car. The 2.5 TDI V6 with the Multitronic transmission, available from July 2002 through 2004, occupied a middle ground in the B6 A4 lineup, offering a blend of performance and fuel efficiency aimed at buyers seeking a refined driving experience. This variant was positioned above the entry-level 1.8T models and below the more potent 3.0 V6 and S4 variants. It primarily served the European market, where diesel engines were – and continue to be – highly favored for their economy and torque.
Technical Specifications
| Brand | Audi |
| Model | A4 |
| Generation | A4 (B6 8E) |
| Type (Engine) | 2.5 TDI V6 (163 Hp) Multitronic |
| Start of production | July, 2002 |
| End of production | 2004 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 9.1 l/100 km (25.8 US mpg, 31 UK mpg, 11 km/l) |
| Fuel consumption (extra urban) | 5.5 l/100 km (42.8 US mpg, 51.4 UK mpg, 18.2 km/l) |
| Fuel consumption (combined) | 6.8 l/100 km (34.6 US mpg, 41.5 UK mpg, 14.7 km/l) |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 8.9 sec |
| Acceleration 0 – 62 mph | 8.9 sec |
| Acceleration 0 – 60 mph | 8.5 sec |
| Maximum speed | 219 km/h (136.08 mph) |
| Weight-to-power ratio | 9.4 kg/Hp, 106.2 Hp/tonne |
| Weight-to-torque ratio | 5 kg/Nm, 202 Nm/tonne |
| Power | 163 Hp @ 4000 rpm |
| Power per litre | 65.3 Hp/l |
| Torque | 310 Nm @ 1400-3600 rpm (228.64 lb.-ft. @ 1400-3600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | BDG, BFC |
| Engine displacement | 2496 cm3 (152.32 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Cylinder Bore | 78.3 mm (3.08 in.) |
| Piston Stroke | 86.4 mm (3.4 in.) |
| Compression ratio | 18.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Coolant | 12 l (12.68 US qt | 10.56 UK qt) |
| Kerb Weight | 1535 kg (3384.1 lbs.) |
| Max. weight | 2085 kg (4596.64 lbs.) |
| Max load | 550 kg (1212.54 lbs.) |
| Trunk (boot) space – minimum | 445 l (15.72 cu. ft.) |
| Trunk (boot) space – maximum | 720 l (25.43 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4548 mm (179.06 in.) |
| Width | 1772 mm (69.76 in.) |
| Height | 1428 mm (56.22 in.) |
| Wheelbase | 2650 mm (104.33 in.) |
| Front track | 1528 mm (60.16 in.) |
| Rear (Back) track | 1526 mm (60.08 in.) |
| Drag coefficient (Cd) | 0.31 |
| Minimum turning circle | 11.1 m (36.42 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the front wheels of the vehicle. |
| Drive wheel | Front wheel drive |
| Number of gears and type of gearbox | automatic transmission Multitronic |
| Front suspension | Independent multi-link suspension |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 205/55 R16 |
| Wheel rims size | 7J x 16 |
Powertrain & Engine Architecture
The heart of this A4 variant is the 2.5-liter V6 TDI diesel engine, identified by engine codes BDG and BFC. This engine utilizes direct injection technology, injecting fuel directly into the combustion chamber under extremely high pressure. This improves combustion efficiency and reduces emissions. The engine features a single turbocharger with an intercooler, boosting power and torque. The valvetrain is a Double Overhead Camshaft (DOHC) design with four valves per cylinder, optimizing airflow for enhanced performance. The Multitronic transmission is a continuously variable transmission (CVT) offering smooth, stepless gear changes. Unlike traditional automatic transmissions with fixed gear ratios, the Multitronic uses a chain-driven system to provide an infinite number of ratios within its operating range. This allows the engine to operate at its most efficient point at all times.
Driving Characteristics
The 2.5 TDI V6 with the Multitronic provided a distinctly different driving experience compared to the more common 1.8T petrol engine or the manual transmission versions of the TDI. While not as overtly sporty as the 3.0 V6, the 2.5 TDI offered ample torque – 310 Nm (228.64 lb-ft) – available from a low 1400 rpm. This made it a relaxed and effortless cruiser, particularly well-suited for highway driving and overtaking. The Multitronic transmission, while smooth, could sometimes feel disconnected from the engine, lacking the direct feel of a manual gearbox. Acceleration to 60 mph took around 8.5 seconds, respectable for its time, but noticeably slower than the manual TDI or the higher-powered petrol variants. The Multitronic’s programming prioritized fuel efficiency over outright performance, resulting in a more subdued throttle response.
Equipment & Trim Levels
The 2.5 TDI V6 Multitronic typically came equipped with a reasonable level of standard features. This included automatic climate control, power windows and mirrors, a CD stereo system, and alloy wheels. Interior upholstery was generally cloth, although leather options were available. Optional extras included a sunroof, upgraded audio systems, parking sensors, and heated front seats. The trim level often dictated the availability of these options, with higher trims offering more standard equipment. The B6 A4 offered a relatively minimalist interior design, focusing on functionality and build quality rather than flashy aesthetics.
Chassis & Braking
The B6 A4 featured fully independent multi-link suspension at both the front and rear, providing a comfortable and controlled ride. The 2.5 TDI models, due to their increased weight compared to the 1.8T, often featured slightly stiffer spring rates to maintain handling balance. Braking was typically accomplished with ventilated discs at the front and solid discs at the rear. Anti-lock Braking System (ABS) was standard. The steering utilized a rack and pinion system, offering precise and responsive control.
Market Reception & Comparison
The 2.5 TDI V6 Multitronic A4 was generally well-received by automotive critics, who praised its refined engine, comfortable ride, and fuel efficiency. However, the Multitronic transmission received mixed reviews, with some finding it smooth and convenient, while others criticized its lack of engagement. Compared to the 1.8T models, the 2.5 TDI offered significantly more torque and better fuel economy, making it a more practical choice for long-distance drivers. Compared to the 3.0 V6, it offered a more economical alternative, albeit with less outright performance. Reliability was generally good, although the Multitronic transmission required more diligent maintenance than a traditional automatic.
Legacy
The 2.5 TDI V6 Multitronic A4 has aged reasonably well, with many examples still on the road today. The engine itself is known for its durability, provided it has been properly maintained. However, the Multitronic transmission is a potential weak point, and requires regular fluid changes and careful driving to avoid premature failure. In the used car market, these models represent a good value for buyers seeking a comfortable, economical, and well-equipped executive car. The B6 A4, in general, is considered a solid and reliable platform, and the 2.5 TDI V6 Multitronic variant offers a unique blend of performance and efficiency that continues to appeal to enthusiasts.
