The Mercedes-Benz ML 450 CDI 4MATIC, produced from 2009 to 2010, represented a potent offering within the second generation (W164) M-Class lineup, particularly after the 2008 facelift. This variant combined a powerful 4.0-liter V8 turbodiesel engine with a seven-speed 7G-TRONIC automatic transmission and Mercedes’ 4MATIC all-wheel-drive system. Positioned as a premium trim, it catered to buyers seeking substantial performance and towing capacity within the luxury SUV segment. The ML 450 CDI filled the gap between the more economical six-cylinder models and the high-performance ML 63 AMG, offering a unique blend of efficiency and capability.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | M-Class |
| Generation | M-Class (W164, facelift 2008) |
| Type (Engine) | ML 450 CDI V8 (306 Hp) 4MATIC 7G-TRONIC |
| Start of production | 2009 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | SUV |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (urban) | 14.2-14.6 l/100 km (16.6 – 16.1 US mpg) |
| Fuel consumption (extra urban) | 8.5-9.1 l/100 km (27.7 – 25.8 US mpg) |
| Fuel consumption (combined) | 10.6-11 l/100 km (22.2 – 21.4 US mpg) |
| CO2 emissions | 279-292 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6.5 sec |
| Acceleration 0 – 62 mph | 6.5 sec |
| Acceleration 0 – 60 mph | 6.2 sec |
| Maximum speed | 235 km/h (146.02 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 7.3 kg/Hp |
| Weight-to-torque ratio | 3.2 kg/Nm |
| Power | 306 Hp @ 3600 rpm |
| Torque | 700 Nm @ 2000-2600 rpm (516.29 lb.-ft. @ 2000-2600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 629 |
| Engine displacement | 3996 cm3 (243.85 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 86 mm (3.39 in.) |
| Piston Stroke | 86 mm (3.39 in.) |
| Compression ratio | 17:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | BiTurbo, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 11.5 l (12.15 US qt | 10.12 UK qt) |
| Coolant capacity | 12 l (12.68 US qt | 10.56 UK qt) |
| Kerb Weight | 2240 kg (4938.35 lbs.) |
| Max. weight | 2950 kg (6503.64 lbs.) |
| Max load | 710 kg (1565.28 lbs.) |
| Trunk (boot) space (minimum) | 833 l (29.42 cu. ft.) |
| Trunk (boot) space (maximum) | 2050 l (72.4 cu. ft.) |
| Fuel tank capacity | 95 l (25.1 US gal | 20.9 UK gal) |
| Permitted trailer load (braked) | 3500 kg (7716.18 lbs.) |
| Permitted trailer load (unbraked) | 750 kg (1653.47 lbs.) |
| Length | 4781 mm (188.23 in.) |
| Width | 1911 mm (75.24 in.) |
| Width (including mirrors) | 2124 mm (83.62 in.) |
| Height | 1815 mm (71.46 in.) |
| Wheelbase | 2915 mm (114.76 in.) |
| Front track | 1636 mm (64.41 in.) |
| Rear track | 1639 mm (64.53 in.) |
| Front overhang | 866 mm (34.09 in.) |
| Rear overhang | 1000 mm (39.37 in.) |
| Ride height (ground clearance) | 186-261 mm (7.32 – 10.28 in.) |
| Minimum turning circle | 11.6 m (38.06 ft.) |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Gearbox | 7 gears, automatic transmission G-TRONIC |
| Front suspension | Double wishbone, Transverse stabilizer, Air suspension |
| Rear suspension | Independent multi-link suspension, Air suspension, Transverse stabilizer |
Powertrain & Engine Architecture
The heart of the ML 450 CDI is the OM 629 4.0-liter V8 diesel engine. This engine utilized a common rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. Two turbochargers, sequentially activated, provided a broad torque curve and minimized turbo lag. The first, smaller turbocharger would spool up quickly at lower engine speeds, providing immediate response, while the larger turbocharger would engage at higher speeds for sustained power. The engine featured a double overhead camshaft (DOHC) valvetrain with four valves per cylinder, enhancing volumetric efficiency. The 7G-TRONIC automatic transmission, a seven-speed unit, was specifically tuned to handle the substantial torque output of the diesel V8. It offered smooth shifts and a wide range of gear ratios, contributing to both performance and fuel efficiency.
Driving Characteristics
The ML 450 CDI offered a markedly different driving experience compared to its six-cylinder siblings or the performance-oriented ML 63 AMG. The abundant 516 lb-ft of torque, available from just 2000 rpm, provided effortless acceleration and strong pulling power. The 7G-TRONIC transmission, while smooth, was geared more towards relaxed cruising and towing than outright sportiness. While 0-60 mph times were quoted around 6.2 seconds, the real-world sensation was one of strong, consistent acceleration rather than a rapid launch. Compared to the manual transmission options available on other M-Class models, the 7G-TRONIC prioritized comfort and ease of use. The 4MATIC all-wheel-drive system provided excellent traction in various conditions, enhancing stability and confidence.
Equipment & Trim Levels
The ML 450 CDI typically came well-equipped as a premium trim level. Standard features included leather upholstery, power-adjustable front seats with memory function, dual-zone automatic climate control, a premium audio system, and parking sensors. Optional extras included a panoramic sunroof, navigation system, rear-seat entertainment system, and upgraded interior trim packages. The exterior styling was largely consistent with other W164 M-Class models, but the 450 CDI often featured unique badging and wheel designs.
Chassis & Braking
The ML 450 CDI utilized a fully independent suspension system, featuring double wishbones at the front and a multi-link setup at the rear. Air suspension was standard, providing adjustable ride height and improved comfort. This allowed drivers to raise the vehicle for off-road conditions or lower it for improved aerodynamics at highway speeds. Braking duties were handled by ventilated discs at all four corners, providing ample stopping power. Anti-lock brakes (ABS) and electronic stability control (ESC) were standard safety features.
Market Reception & Comparison
The ML 450 CDI was generally well-received by automotive critics, who praised its powerful engine, comfortable ride, and luxurious interior. However, its relatively high price and fuel consumption were noted drawbacks. Compared to the ML 350, the 450 CDI offered significantly more performance and towing capacity, but at a higher cost. The ML 63 AMG, while offering even greater performance, was considerably more expensive and focused on a more sporting driving experience. Fuel economy, while respectable for a V8 SUV, was lower than that of the six-cylinder models.
Legacy
The OM 629 engine, while robust, is known to require diligent maintenance, particularly regarding the diesel particulate filter (DPF) and fuel injectors. Proper servicing is crucial to avoid costly repairs. Today, the ML 450 CDI represents a relatively rare and desirable variant within the W164 M-Class range. Well-maintained examples command a premium in the used car market, appealing to buyers seeking a powerful and luxurious diesel SUV with a unique character. Its combination of performance, comfort, and capability continues to make it a compelling option for those willing to invest in its upkeep.
