The BMW 4 Series Gran Coupe (G26) 420d, produced from June 2021 to June 2024, represents a compelling blend of practicality and performance within the 4 Series lineup. Positioned as a mid-range offering, this variant combined a 2.0-liter turbocharged diesel engine with a 48-volt mild hybrid system and BMW’s xDrive all-wheel-drive system, paired with an 8-speed Steptronic automatic transmission. The G26 Gran Coupe, built on the BMW 1HX0 platform, aimed to provide a more spacious and versatile alternative to the traditional 4 Series Coupe while maintaining a sporty driving experience. This model catered to buyers seeking a premium four-door coupe with enhanced fuel efficiency and all-weather capability.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Gran Coupe (G26) |
| Type (Engine) | 420d (190 Hp) Mild Hybrid xDrive Steptronic |
| Start of production | June, 2021 |
| End of production | June, 2024 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Coupe |
| Seats | 5 |
| Doors | 5 |
| Combined fuel consumption (WLTP) | 5.1-5.7 l/100 km (46.1 – 41.3 US mpg) |
| CO2 emissions (WLTP) | 133-150 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.6 sec |
| Acceleration 0 – 62 mph | 7.6 sec |
| Acceleration 0 – 60 mph | 7.2 sec |
| Maximum speed | 233 km/h (144.78 mph) |
| Emission standard | Euro 6d |
| Weight-to-power ratio | 9.3 kg/Hp |
| Weight-to-torque ratio | 4.4 kg/Nm |
| Gross battery capacity | 0.4 kWh |
| Battery voltage | 48 V |
| Battery technology | Lithium-ion (Li-Ion) |
| Electric motor power | 11 Hp |
| Electric motor Torque | 25 Nm (18.44 lb.-ft.) |
| Power | 190 Hp @ 4000 rpm |
| Torque | 400 Nm @ 1750-2500 rpm (295.02 lb.-ft. @ 1750-2500 rpm) |
| Engine displacement | 1995 cm3 (121.74 cu. in.) |
| Number of cylinders | 4 |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 16.5:1 |
| Fuel injection system | Diesel Commonrail |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Coolant capacity | 7 l (7.4 US qt | 6.16 UK qt) |
| Kerb Weight | 1760 kg (3880.14 lbs.) |
| Max. weight | 2315 kg (5103.7 lbs.) |
| Trunk (boot) space – minimum | 470 l (16.6 cu. ft.) |
| Trunk (boot) space – maximum | 1290 l (45.56 cu. ft.) |
| Fuel tank capacity | 59 l (15.59 US gal | 12.98 UK gal) |
| Length | 4783 mm (188.31 in.) |
| Width | 1852 mm (72.91 in.) |
| Height | 1442 mm (56.77 in.) |
| Wheelbase | 2856 mm (112.44 in.) |
| Tires size | 225/55 R17 |
| Number of gears | 8 |
| Gearbox type | automatic transmission Steptronic |
Powertrain & Engine Architecture
The heart of the 420d Gran Coupe is BMW’s B47D20B 2.0-liter inline-four cylinder diesel engine. This engine utilizes a sophisticated common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. A twin-scroll turbocharger with intercooling further enhances performance and responsiveness. The engine produces 190 horsepower at 4,000 rpm and a substantial 400 Nm (295 lb-ft) of torque between 1,750 and 2,500 rpm. The inclusion of a 48V mild hybrid system adds a small electric motor (11 hp and 25 Nm of torque) that assists the engine during acceleration and allows for smoother start-stop operation, improving fuel economy. The 8-speed Steptronic automatic transmission is a key component, offering quick and precise gear changes. It’s programmed for both efficiency and performance, adapting to driving style and conditions.
Driving Characteristics
The 420d xDrive Gran Coupe delivers a refined and comfortable driving experience. While not as overtly sporty as higher-powered 4 Series variants, the 190 hp engine and all-wheel-drive system provide ample performance for everyday driving and highway cruising. The mild hybrid system contributes to a seamless power delivery, minimizing turbo lag. The Steptronic transmission is well-tuned, offering smooth shifts in both automatic and manual modes. Compared to a manual transmission version (not widely available in this configuration), the automatic prioritizes ease of use and fuel efficiency. Against the more powerful 430i or M440i models, the 420d offers a more economical option, sacrificing some outright speed for improved fuel consumption.
Equipment & Trim Levels
The 420d Gran Coupe typically came standard with a comprehensive suite of features, including BMW’s iDrive infotainment system with a central touchscreen display, leatherette upholstery, automatic climate control, and a suite of driver-assistance systems like lane departure warning and forward collision warning. Optional extras included premium leather upholstery, a panoramic sunroof, a head-up display, and a Harman Kardon sound system. Trim levels varied by market, but generally offered packages that added cosmetic enhancements, upgraded interior materials, and additional technology features. The xDrive all-wheel-drive system was a standard feature on the 420d, providing enhanced traction and stability in all weather conditions.
Chassis & Braking
The G26 Gran Coupe features a sophisticated chassis designed to balance comfort and handling. The front suspension utilizes a spring strut design with a transverse stabilizer bar, while the rear employs an independent multi-link suspension, also with a stabilizer bar. This setup provides a comfortable ride while minimizing body roll during cornering. Braking duties are handled by ventilated discs on all four wheels, providing ample stopping power. The electronic stability control system (DSC) works in conjunction with the xDrive all-wheel-drive system to maintain optimal traction and stability. The suspension tuning was generally softer than that of the 4 Series Coupe, reflecting the Gran Coupe’s focus on comfort and practicality.
Market Reception & Comparison
The 420d xDrive Gran Coupe was generally well-received by automotive critics. It was praised for its fuel efficiency, comfortable ride, and spacious interior. However, some reviewers noted that the engine lacked the outright performance of its more powerful siblings. Compared to other diesel-powered Gran Coupes in its class, such as the Audi A5 Sportback TDI, the BMW offered a more engaging driving experience and a more premium interior. Fuel economy figures of 5.1-5.7 l/100 km (46.1-41.3 mpg) were competitive within its segment. Reliability reports generally indicated good long-term reliability, although diesel particulate filter (DPF) issues could occur with infrequent long-distance driving.
Legacy
The BMW 420d xDrive Gran Coupe (G26) represents a significant step in BMW’s strategy of offering a wider range of models to cater to diverse customer needs. The combination of a fuel-efficient diesel engine, mild hybrid technology, and all-wheel drive proved popular with buyers seeking a practical and refined four-door coupe. On the used car market, these models continue to hold their value reasonably well, particularly those with lower mileage and a full service history. The B47 engine, while known for its efficiency, requires regular maintenance, including oil changes and DPF regeneration, to ensure long-term reliability. The G26 Gran Coupe remains a compelling option for buyers seeking a premium, fuel-efficient, and versatile vehicle.
