The Audi A6 Sedan (C8) 40 TDI, produced from 2018 to May 2023, represents a key offering in Audi’s mid-size executive car lineup. This variant, equipped with a 2.0-liter turbocharged diesel engine producing 204 horsepower and paired with a 7-speed S tronic dual-clutch transmission, incorporates mild hybrid technology. Positioned as a balance between performance and efficiency, the 40 TDI aimed to appeal to buyers seeking a refined driving experience with reduced running costs. It served as a popular alternative to the more powerful petrol variants and the higher-output diesel models within the C8 A6 range.
Technical Specifications
| Brand | Audi |
| Model | A6 |
| Generation | A6 Sedan (C8) |
| Type (Engine) | 40 TDI (204 Hp) Mild Hybrid S tronic |
| Start of production | 2018 |
| End of production | May, 2023 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Combined fuel consumption (WLTP) | 5.5-6.0 l/100 km (42.8 – 39.2 US mpg, 51.4 – 47.1 UK mpg, 18.2 – 16.7 km/l) |
| CO2 emissions (WLTP) | 145-158 g/km |
| Fuel consumption (urban) | 4.8-5.2 l/100 km (49 – 45.2 US mpg, 58.9 – 54.3 UK mpg, 20.8 – 19.2 km/l) |
| Fuel consumption (extra urban) | 4.0-4.4 l/100 km (58.8 – 53.5 US mpg, 70.6 – 64.2 UK mpg, 25 – 22.7 km/l) |
| Fuel consumption (combined) | 4.3-4.7 l/100 km (54.7 – 50 US mpg, 65.7 – 60.1 UK mpg, 23.3 – 21.3 km/l) |
| CO2 emissions | 112-124 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 8.1 sec |
| Acceleration 0 – 62 mph | 8.1 sec |
| Acceleration 0 – 60 mph | 7.7 sec |
| Maximum speed | 246 km/h (152.86 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 8.1 kg/Hp, 124 Hp/tonne |
| Weight-to-torque ratio | 4.1 kg/Nm, 243.2 Nm/tonne |
| Power | 204 Hp @ 3750-4200 rpm |
| Torque | 400 Nm @ 1750-3000 rpm (295.02 lb.-ft. @ 1750-3000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | DFBA |
| Engine displacement | 1968 cm3 (120.09 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Coolant capacity | 10.8 l (11.41 US qt | 9.5 UK qt) |
| Kerb Weight | 1645 kg (3626.6 lbs.) |
| Max. weight | 2255 kg (4971.42 lbs.) |
| Max load | 610 kg (1344.82 lbs.) |
| Trunk (boot) space – minimum | 530 l (18.72 cu. ft.) |
| Fuel tank capacity | 63 l (16.64 US gal | 13.86 UK gal) |
| Max. roof load | 90 kg (198.42 lbs.) |
| Permitted trailer load with brakes (8%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load with brakes (12%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 95 kg (209.44 lbs.) |
| Length | 4939 mm (194.45 in.) |
| Width | 1886 mm (74.25 in.) |
| Width including mirrors | 2110 mm (83.07 in.) |
| Height | 1457 mm (57.36 in.) |
| Wheelbase | 2924 mm (115.12 in.) |
| Front track | 1630 mm (64.17 in.) |
| Rear track | 1617 mm (63.66 in.) |
| Front overhang | 920 mm (36.22 in.) |
| Rear overhang | 1095 mm (43.11 in.) |
| Drag coefficient (Cd) | 0.27 |
| Minimum turning circle | 12.1 m (39.7 ft.) |
| Drivetrain Architecture | ICE and electric motor drive the front wheels |
| Drive wheel | Front wheel drive |
| Number of gears | 7 |
| Gearbox type | Automatic transmission S tronic |
| Front suspension | Independent multi-link suspension |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
Powertrain & Engine Architecture
The heart of the A6 40 TDI is the DFBA engine, a 2.0-liter inline-four cylinder diesel. This engine utilizes a sophisticated common rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. A turbocharger with an intercooler further enhances performance by forcing more air into the cylinders. The engine produces 204 horsepower at 3750-4200 rpm and a substantial 400 Nm (295 lb-ft) of torque between 1750 and 3000 rpm. The mild hybrid system, a 48-volt electrical system, incorporates a belt starter generator (BSG) and a small lithium-ion battery. This system allows for features like extended engine-off coasting, regenerative braking, and smoother start-stop operation, improving fuel efficiency. The 7-speed S tronic dual-clutch transmission provides rapid and seamless gear changes, contributing to both performance and efficiency.
Driving Characteristics
The 40 TDI offers a comfortable and refined driving experience. While not as overtly sporty as the higher-powered variants, the 204 hp engine provides ample power for everyday driving and highway cruising. The S tronic transmission is quick to respond, and the engine delivers strong low-end torque, making overtaking maneuvers relatively effortless. The mild hybrid system is largely transparent to the driver, working in the background to optimize fuel consumption. Compared to the manual transmission versions, the S tronic offers greater convenience, particularly in urban environments. The gear ratios are tuned for a balance between acceleration and fuel economy, prioritizing smooth operation over outright performance.
Equipment & Trim Levels
The A6 40 TDI typically came well-equipped as standard. Features included Audi’s Virtual Cockpit digital instrument cluster, a touchscreen infotainment system with Apple CarPlay and Android Auto compatibility, leather upholstery, three-zone automatic climate control, and a suite of driver-assistance systems such as lane departure warning and automatic emergency braking. Optional extras included a premium sound system, adaptive cruise control, a head-up display, and matrix LED headlights. Trim levels varied by market, but generally offered increasing levels of luxury and technology.
Chassis & Braking
The C8 A6 features a sophisticated chassis design with independent multi-link suspension at both the front and rear. This setup provides a comfortable ride quality while maintaining good handling characteristics. The 40 TDI variant typically came equipped with ventilated disc brakes on all four wheels, providing ample stopping power. The electronic stability control (ESC) system and anti-lock braking system (ABS) are standard features, enhancing safety and control. The suspension tuning is geared towards comfort, with a focus on absorbing bumps and providing a stable ride.
Market Reception & Comparison
The A6 40 TDI was generally well-received by automotive critics. It was praised for its refined engine, comfortable ride, and advanced technology. Fuel economy was a significant selling point, with the mild hybrid system contributing to impressive real-world figures. Compared to the more powerful 45 TDI variant, the 40 TDI offered a more affordable entry point into the A6 range, albeit with slightly less performance. Against competitors like the BMW 5 Series and Mercedes-Benz E-Class, the A6 40 TDI held its own, offering a compelling combination of luxury, technology, and efficiency.
Legacy
The DFBA engine, in its various iterations, has proven to be a reliable and durable powerplant. While diesel engines, in general, have faced increased scrutiny in recent years, the A6 40 TDI remains a popular choice in the used car market. The S tronic transmission is generally reliable, but requires regular servicing to ensure optimal performance. The mild hybrid system has also proven to be relatively trouble-free. Overall, the A6 40 TDI represents a well-engineered and well-equipped executive sedan that continues to offer a compelling value proposition for buyers seeking a refined and efficient driving experience.
