The Mercedes-Benz S 450 4MATIC, produced from 2009 to 2010, represented a significant iteration within the W221 S-Class facelift. Positioned as a mid-range offering in the S-Class lineup, it bridged the gap between the entry-level S 350 and the more powerful S 550 and S 63 AMG models. This variant combined a naturally aspirated 4.7-liter V8 engine with Mercedes-Benz’s 7G-TRONIC automatic transmission and the 4MATIC all-wheel-drive system, aiming to deliver a balance of performance, luxury, and all-weather capability. The W221 facelift, introduced in 2009, brought revised styling, updated technology, and improved efficiency compared to the pre-facelift models.
Powertrain & Engine Architecture
The heart of the S 450 4MATIC is the M273.924 engine, a 4.7-liter (4663 cc) naturally aspirated V8. This engine utilizes a three-valve-per-cylinder design (two intake, one exhaust) and multi-port fuel injection. The engine produces 340 horsepower (hp) at 6000 rpm and 460 Newton-meters (339.28 lb-ft) of torque between 2700 and 5000 rpm. The compression ratio is 10.5:1. The engine is longitudinally mounted in the front of the vehicle. The M273 engine family was known for its relatively smooth operation and robust construction, though it did incorporate balance shaft technology to mitigate vibrations inherent in a 90-degree V8 configuration.
The 7G-TRONIC automatic transmission (722.906) is a seven-speed planetary automatic transmission. It features a torque converter lock-up clutch to improve efficiency at cruising speeds. The transmission offers selectable driving modes, including Comfort and Sport, which adjust shift points and responsiveness. The 7G-TRONIC was a sophisticated transmission for its time, known for its smooth shifts and wide gear ratio spread. The 4MATIC system is a full-time all-wheel-drive system, utilizing a center differential to distribute torque between the front and rear axles. This system enhances traction and stability, particularly in adverse weather conditions.
Engine Code Specifics
The M273.924 engine code specifically denotes the 4.7-liter V8 configuration with the features outlined above. Early versions of the M273 engine were known to experience issues with balance shaft sprockets, leading to potential engine noise. However, this issue was largely addressed in later production years, including those of the 2009-2010 S 450 4MATIC. Regular oil changes with the correct specification (Mercedes-Benz approved) are crucial for maintaining the longevity of this engine.
Driving Characteristics
The S 450 4MATIC offered a refined and comfortable driving experience. The 340 hp engine provided ample power for effortless cruising and confident acceleration. Acceleration from 0 to 60 mph was achieved in approximately 5.6-5.9 seconds, making it a reasonably quick vehicle for its size and class. The 7G-TRONIC transmission contributed to smooth and seamless gear changes, enhancing the overall driving experience. The 4MATIC all-wheel-drive system provided enhanced grip and stability, particularly on slippery surfaces. Compared to the S 350, the S 450 offered noticeably more power and a more responsive feel. However, it lacked the outright performance of the S 550 or the S 63 AMG. The gear ratios were tuned for a balance between acceleration and fuel efficiency, with a relatively tall seventh gear for highway cruising.
Equipment & Trim Levels
The S 450 4MATIC came standard with a comprehensive array of luxury features. Standard equipment typically included leather upholstery, power-adjustable heated and ventilated front seats, a premium sound system, a navigation system, dual-zone automatic climate control, and a sunroof. The interior featured wood trim and high-quality materials throughout. Optional extras included rear seat entertainment, massaging seats, a panoramic sunroof, and advanced driver-assistance systems such as Distronic Plus adaptive cruise control and lane-keeping assist. Trim levels were relatively limited, with most customization occurring through the selection of individual options. The S 450 4MATIC generally offered a higher level of standard equipment than the base S 350, reflecting its position as a mid-range model.
Chassis & Braking
The S 450 4MATIC utilized an independent suspension system on all four wheels. The front suspension featured multi-link design with coil springs and adaptive damping. The rear suspension also employed a multi-link setup with coil springs and adaptive damping. This suspension configuration provided a comfortable ride while maintaining good handling characteristics. The car featured disc brakes on all four wheels, with ABS (Anti-lock Braking System) and Electronic Stability Program (ESP) as standard safety features. The braking system was designed to provide strong and consistent stopping power. The 4MATIC system added weight compared to rear-wheel-drive S-Class models, necessitating slightly stiffer spring rates and damper settings to maintain handling balance.
Market Reception & Comparison
The S 450 4MATIC was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and capable performance. The 4MATIC all-wheel-drive system was seen as a significant advantage in regions with inclement weather. Fuel economy, however, was a common criticism, with combined fuel consumption ranging from 11.0 to 11.1 liters per 100 kilometers (21.4-21.2 US mpg). Compared to the S 350, the S 450 offered a noticeable performance upgrade, but at the cost of slightly lower fuel economy. Compared to the S 550, the S 450 provided a more affordable entry point into the S-Class range while still offering a luxurious and capable driving experience. Reliability was generally good, although potential issues with the balance shaft sprockets in earlier M273 engines were a concern.
Technical Specifications
| Body Type | Sedan, 4 Doors, 5 Seats |
| Engine Type | Petrol (Gasoline) |
| Engine Displacement | 4663 cm3 (284.55 cu. in.) |
| Number of Cylinders | 8 |
| Engine Configuration | V-engine |
| Compression Ratio | 10.5:1 |
| Fuel Injection System | Multi-port manifold injection |
| Power | 340 Hp @ 6000 rpm |
| Torque | 460 Nm @ 2700-5000 rpm (339.28 lb.-ft.) |
| Transmission | 7-speed automatic G-TRONIC |
| Drive Type | All wheel drive (4×4) |
| Acceleration 0-100 km/h | 5.9 sec |
| Acceleration 0-60 mph | 5.6 sec |
| Maximum Speed | 250 km/h (155.34 mph) |
| Kerb Weight | 1955 kg (4310.04 lbs.) |
| Max. Weight | 2640 kg (5820.2 lbs.) |
| Fuel Tank Capacity | 90 l (23.78 US gal | 19.8 UK gal) |
| Trunk (boot) Space | 560 l (19.78 cu. ft.) |
| Length | 5096 mm (200.63 in.) |
| Width | 1871 mm (73.66 in.) |
| Height | 1479 mm (58.23 in.) |
Legacy
The S 450 4MATIC, while a relatively short-lived model, remains a desirable used car option for those seeking a luxurious and capable S-Class. The M273 engine, when properly maintained, has proven to be a durable and reliable powerplant. However, potential buyers should be aware of the possibility of balance shaft sprocket wear and ensure that regular oil changes have been performed. The 7G-TRONIC transmission is also generally reliable, but may require servicing as it ages. Today, these vehicles can be found at relatively affordable prices, making them an attractive entry point into the world of Mercedes-Benz luxury. The combination of a powerful V8 engine, all-wheel-drive capability, and a well-equipped interior continues to appeal to buyers seeking a comfortable and refined driving experience.
