The Mercedes-Benz GLS 350d 4MATIC G-TRONIC, produced from 2015 to 2019, represents a significant iteration of the X166 GLS generation. Positioned as a mid-range offering within the GLS lineup, it aimed to balance luxury, capability, and fuel efficiency in the large SUV segment. This variant catered to buyers seeking a powerful diesel engine paired with the convenience of an automatic transmission and Mercedes-Benz’s renowned all-wheel-drive system. The X166 GLS, introduced as a replacement for the GL-Class, offered a more refined and technologically advanced package compared to its predecessor, solidifying Mercedes-Benz’s presence in the full-size luxury SUV market.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | GLS |
| Generation | GLS (X166) |
| Type | GLS 350d (258 Hp) 4MATIC G-TRONIC |
| Start of production | 2015 |
| End of production | 2019 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | SUV |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (urban) | 8.2-7.6 l/100 km (28.7 – 30.9 US mpg, 34.4 – 37.2 UK mpg, 12.2 – 13.2 km/l) |
| Fuel consumption (extra urban) | 7.2-6.7 l/100 km (32.7 – 35.1 US mpg, 39.2 – 42.2 UK mpg, 13.9 – 14.9 km/l) |
| Fuel consumption (combined) | 7.6-7.1 l/100 km (30.9 – 33.1 US mpg, 37.2 – 39.8 UK mpg, 13.2 – 14.1 km/l) |
| CO2 emissions | 199-185 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.8 sec |
| Acceleration 0 – 62 mph | 7.8 sec |
| Acceleration 0 – 60 mph | 7.4 sec |
| Maximum speed | 222 km/h (137.94 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 9.2 kg/Hp, 108.4 Hp/tonne |
| Weight-to-torque ratio | 3.8 kg/Nm, 260.5 Nm/tonne |
| Power | 258 Hp @ 3400 rpm |
| Torque | 620 Nm @ 1600-2400 rpm (457.29 lb.-ft. @ 1600-2400 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 642.826 |
| Engine displacement | 2987 cm3 (182.28 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Compression ratio | 15.5:1 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Kerb Weight | 2380 kg (5247 lbs.) |
| Max. weight | 3250 kg (7165.02 lbs.) |
| Max load | 870 kg (1918.02 lbs.) |
| Trunk (boot) space – minimum | 680 l (24.01 cu. ft.) |
| Trunk (boot) space – maximum | 2300 l (81.22 cu. ft.) |
| Fuel tank capacity | 100 l (26.42 US gal | 22 UK gal) |
| Max. roof load | 100 kg (220.46 lbs.) |
| Permitted trailer load with brakes (12%) | 3500 kg (7716.18 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 5130 mm (201.97 in.) |
| Width | 1934 mm (76.14 in.) |
| Width including mirrors | 2141 mm (84.29 in.) |
| Height | 1850 mm (72.83 in.) |
| Wheelbase | 3075 mm (121.06 in.) |
| Front track | 1655 mm (65.16 in.) |
| Rear (Back) track | 1675 mm (65.94 in.) |
| Minimum turning circle | 12.40 m (40.68 ft.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 9 gears, automatic transmission G-TRONIC |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 265/60 R18 |
| Wheel rims size | 18 |
Powertrain & Engine Architecture
The GLS 350d is powered by the OM 642.826, a 3.0-liter turbocharged diesel V6 engine. This engine is a cornerstone of Mercedes-Benz’s diesel offerings, known for its robust construction and refined operation. The OM 642 features a common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger with an intercooler further enhances performance and efficiency. The engine produces 258 horsepower at 3400 rpm and a substantial 620 Nm (457 lb-ft) of torque between 1600 and 2400 rpm. This broad torque curve provides strong pulling power across a wide range of engine speeds. Paired with the engine is the 9G-TRONIC nine-speed automatic transmission. This transmission is designed for smooth shifts and improved fuel economy, utilizing a wide gear ratio spread to keep the engine operating in its optimal range. The 9G-TRONIC also features paddle shifters for manual gear selection.
Driving Characteristics
The GLS 350d 4MATIC offers a comfortable and capable driving experience. The abundant torque from the diesel engine provides effortless acceleration, particularly in everyday driving situations. While not as overtly sporty as some of its gasoline-powered siblings, the 350d delivers a respectable 0-60 mph time of around 7.4 seconds. The 9G-TRONIC transmission contributes to a relaxed cruising experience, with the high gear count minimizing engine revs at highway speeds. The 4MATIC all-wheel-drive system provides excellent traction in various conditions, enhancing stability and confidence. Compared to the higher-output GLS 450 or AMG variants, the 350d prioritizes fuel efficiency and relaxed cruising over outright performance. The manual transmission options available on other GLS models offered a more engaging driving experience, but at the cost of some convenience.
Equipment & Trim Levels
The GLS 350d 4MATIC typically came well-equipped, reflecting its position as a luxury SUV. Standard features generally included leather upholstery, power-adjustable front seats with memory function, a premium sound system, dual-zone automatic climate control, and a rearview camera. Mercedes-Benz’s COMAND infotainment system with a central display screen was also standard. Optional extras included a panoramic sunroof, advanced driver-assistance systems (such as adaptive cruise control and lane-keeping assist), rear-seat entertainment, and upgraded interior trim options. Trim levels were often differentiated by the availability of these optional packages, allowing buyers to customize their GLS to their preferences.
Chassis & Braking
The GLS 350d utilizes a robust chassis designed to handle its substantial weight. It features a double-wishbone front suspension and an independent multi-link rear suspension, providing a comfortable ride and good handling characteristics. Ventilated disc brakes are fitted on all four wheels, providing ample stopping power. The braking system is enhanced by ABS (Anti-lock Braking System) and electronic stability control. Due to the vehicle’s weight, rear brakes were often larger than those found on lighter Mercedes-Benz models. Stabilizer bars are present on both axles to reduce body roll during cornering.
Market Reception & Comparison
The GLS 350d 4MATIC was generally well-received by automotive critics. It was praised for its comfortable ride, spacious interior, and fuel-efficient diesel engine. The combination of power and economy made it a practical choice for buyers who frequently travel long distances. Compared to the GLS 450, the 350d offered similar levels of luxury and features at a lower price point, albeit with slightly less performance. The 350d also offered better fuel economy than the gasoline-powered models. However, some critics noted that the diesel engine could be somewhat noisy compared to the smoother gasoline engines.
Legacy
The OM 642 engine family, including the OM 642.826 found in the GLS 350d, has a reputation for durability and longevity. With proper maintenance, these engines can reliably exceed 200,000 miles. The 9G-TRONIC transmission has also proven to be a reliable unit. On the used car market, the GLS 350d 4MATIC represents a good value proposition, offering a luxurious and capable SUV at a more affordable price than newer models. However, potential buyers should be aware of the potential maintenance costs associated with diesel engines, such as diesel particulate filter (DPF) maintenance and potential issues with the emissions control system.
