The Mercedes-Benz E 320 CDI, produced between 2005 and 2006, was a significant variant within the W211 E-Class generation. Representing a blend of performance and efficiency, this model combined a potent 3.0-liter V6 turbodiesel engine with Mercedes’ advanced 7G-TRONIC automatic transmission. Positioned as a mid-to-upper range offering, the E 320 CDI catered to buyers seeking a luxurious and capable sedan with strong fuel economy and substantial torque. It served as a popular alternative to the gasoline-powered E 320 and E 350 models, particularly in European markets where diesel engines were favored.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | E-class |
| Generation | E-class (W211) |
| Type (Engine) | E 320 CDI V6 (224 Hp) 7G-TRONIC |
| Start of production | 2005 |
| End of production | 2006 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 10.3 l/100 km (22.8 US mpg) |
| Fuel consumption (extra urban) | 5.6 l/100 km (42 US mpg) |
| Fuel consumption (combined) | 7.3 l/100 km (32.2 US mpg) |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6.8 sec |
| Acceleration 0 – 62 mph | 6.8 sec |
| Acceleration 0 – 60 mph | 6.5 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 7.8 kg/Hp |
| Weight-to-torque ratio | 3.4 kg/Nm |
| Power | 224 Hp @ 3800 rpm |
| Torque | 510 Nm @ 1600 rpm (376.16 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 642.920 |
| Engine displacement | 2987 cm3 (182.28 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Coolant capacity | 7.5 l (7.93 US qt | 6.6 UK qt) |
| Kerb Weight | 1740 kg (3836.04 lbs.) |
| Max. weight | 2265 kg (4993.47 lbs.) |
| Max load | 525 kg (1157.43 lbs.) |
| Trunk (boot) space – minimum | 540 l (19.07 cu. ft.) |
| Fuel tank capacity | 65 l (17.17 US gal | 14.3 UK gal) |
| Permitted trailer load with brakes (12%) | 1900 kg (4188.78 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 4818 mm (189.69 in.) |
| Width | 1822 mm (71.73 in.) |
| Height | 1452 mm (57.17 in.) |
| Wheelbase | 2854 mm (112.36 in.) |
| Front track | 1577 mm (62.09 in.) |
| Rear track | 1570 mm (61.81 in.) |
| Drag coefficient (Cd) | 0.28 |
| Minimum turning circle | 11.4 m (37.4 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 7 |
| Gearbox type | Automatic transmission 7G-TRONIC |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Hydraulic Steering |
| Tires size | 225/55 R16 |
| Wheel rims size | 16 |
Powertrain & Engine Architecture
The heart of the E 320 CDI is the OM 642.920, a 3.0-liter V6 diesel engine. This engine utilizes a common rail direct injection system, delivering fuel at extremely high pressure for optimized combustion. A variable geometry turbocharger (VGT) and intercooler further enhance performance and efficiency. The V6 configuration provides inherent smoothness compared to inline engines, and the diesel common rail system allowed for precise fuel metering, resulting in reduced emissions and improved refinement. The engine produces 224 horsepower at 3800 rpm and a substantial 510 Nm (376 lb-ft) of torque at just 1600 rpm. This torque output is a key characteristic of the engine, providing strong acceleration and effortless cruising. The 7G-TRONIC automatic transmission, a seven-speed unit, was a significant advancement over previous Mercedes automatics. It offered smoother shifts, quicker response times, and a wider gear ratio spread, contributing to both performance and fuel economy. The transmission featured a torque converter lock-up clutch that engaged in most gears, minimizing slippage and improving efficiency.
Driving Characteristics
The E 320 CDI offered a distinctly different driving experience compared to its gasoline counterparts. The abundant low-end torque meant strong acceleration from a standstill and effortless overtaking. While not as outright quick as the E 350, the E 320 CDI felt remarkably capable in real-world driving situations. The 7G-TRONIC transmission was well-programmed, providing smooth and timely shifts. The gear ratios were optimized for both fuel efficiency and performance, allowing the engine to operate within its peak torque band for most of the time. Compared to the manual transmission options available on other E-Class models, the automatic offered greater convenience and ease of use, particularly in city traffic. However, some enthusiasts preferred the greater control offered by a manual gearbox.
Equipment & Trim Levels
The E 320 CDI typically came well-equipped, reflecting its position as a premium sedan. Standard features included leather upholstery, automatic climate control, a multi-function steering wheel, and a premium audio system. Optional extras included a sunroof, navigation system, heated seats, and advanced driver-assistance systems like Distronic adaptive cruise control. Trim levels varied depending on the market, but generally, the E 320 CDI was offered with a range of interior finishes and exterior styling options. The interior typically featured wood trim accents and high-quality materials, creating a luxurious and comfortable cabin environment.
Chassis & Braking
The W211 E-Class featured a sophisticated chassis design. The front suspension utilized a double wishbone setup, while the rear employed an independent multi-link suspension with a stabilizer bar. This configuration provided a comfortable ride and good handling characteristics. The E 320 CDI was equipped with ventilated disc brakes at the front and solid disc brakes at the rear. Anti-lock braking system (ABS) was standard, enhancing safety and control during emergency braking. The steering was a rack-and-pinion system with hydraulic power assistance, providing precise and responsive steering feel.
Market Reception & Comparison
The E 320 CDI was generally well-received by automotive critics. It was praised for its strong performance, excellent fuel economy, and refined driving experience. Compared to the gasoline-powered E 320 and E 350 models, the E 320 CDI offered comparable performance with significantly better fuel efficiency. It also provided a quieter and more relaxed driving experience, thanks to the inherent smoothness of the diesel engine and the well-tuned automatic transmission. However, some critics noted that the diesel engine was slightly noisier than the gasoline engines, particularly at idle. In terms of reliability, the OM 642 engine proved to be generally robust, although some owners reported issues with the diesel particulate filter (DPF) and the fuel injection system.
Legacy
The E 320 CDI, and the OM 642 engine family as a whole, has proven to be a durable and reliable powertrain. Today, well-maintained examples are still relatively common on the used car market. The engine’s robust construction and relatively simple design contribute to its longevity. However, potential buyers should be aware of the potential for issues with the DPF and fuel injection system, and regular maintenance is crucial to ensure continued reliability. The E 320 CDI represents a high point in Mercedes-Benz diesel technology, offering a compelling combination of performance, efficiency, and luxury.
