The Infiniti M IV (Y51) M30d V6 Automatic, produced between 2010 and 2014, represents a significant offering in the mid-size luxury sedan segment. Positioned as a diesel-powered variant within the fourth generation of the M series, the M30d aimed to provide a blend of performance, efficiency, and refinement for European and select international markets. It utilized the Y51 platform, shared with the Nissan Fuga and other Nissan models, and was intended to compete with established German rivals like the BMW 5 Series and Audi A6. This particular configuration, pairing the 3.0-liter V6 turbodiesel with a seven-speed automatic transmission, was a key component of Infiniti’s strategy to broaden its appeal with a more fuel-conscious clientele.
Technical Specifications
| Brand | Infiniti |
| Model | M |
| Generation | M IV (Y51) |
| Type (Engine) | M30d V6 (238 Hp) Automatic |
| Start of production | 2010 |
| End of production | 2014 |
| 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) | 5.9 l/100 km (39.9 US mpg) |
| Fuel consumption (combined) | 7.5 l/100 km (31.4 US mpg) |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6.9 sec |
| Acceleration 0 – 62 mph | 6.9 sec |
| Acceleration 0 – 60 mph | 6.6 sec |
| Maximum speed | 249 km/h (154.72 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 7.8 kg/Hp |
| Weight-to-torque ratio | 3.4 kg/Nm |
| Power | 238 Hp @ 3750 rpm |
| Torque | 550 Nm @ 1750-2500 rpm (405.66 lb.-ft.) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | V9X |
| Engine displacement | 2993 cm3 (182.64 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 5.3 l (5.6 US qt | 4.66 UK qt) |
| Coolant capacity | 12.6 l (13.31 US qt | 11.09 UK qt) |
| Kerb Weight | 1845 kg (4067.53 lbs.) |
| Max. weight | 2395 kg (5280.07 lbs.) |
| Max load | 550 kg (1212.54 lbs.) |
| Trunk (boot) space – minimum | 450 l (15.89 cu. ft.) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Permitted trailer load with brakes (12%) | 2000 kg (4409.25 lbs.) |
| Length | 4945 mm (194.69 in.) |
| Width | 1845 mm (72.64 in.) |
| Height | 1500 mm (59.06 in.) |
| Wheelbase | 2900 mm (114.17 in.) |
| Front track | 1575 mm (62.01 in.) |
| Rear (Back) track | 1570 mm (61.81 in.) |
| Ride height (ground clearance) | 144 mm (5.67 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 7 gears, automatic transmission |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| Front brakes | Ventilated discs, 355 mm |
| Rear brakes | Ventilated discs, 350 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 245/50 R18 |
| Wheel rims size | 18 |
Powertrain & Engine Architecture
The heart of the M30d is the V9X 3.0-liter V6 turbodiesel engine. This engine, a product of the Renault-Nissan Alliance, utilizes a common rail direct injection system, delivering fuel at extremely high pressure for optimized combustion. The engine features a single variable geometry turbocharger (VGT) and an intercooler to enhance power and efficiency. The DOHC valvetrain, with four valves per cylinder, contributes to the engine’s breathing efficiency. The engine’s output of 238 horsepower at 3750 rpm and a substantial 550 Nm (405.66 lb.-ft.) of torque between 1750 and 2500 rpm provides strong acceleration and effortless cruising. The seven-speed automatic transmission, sourced from Jatco (a Nissan subsidiary), is designed for smooth and responsive shifts. It features adaptive shift logic, adjusting shift points based on driving conditions and driver input. The transmission is geared towards maximizing fuel economy while still providing adequate performance.
Driving Characteristics
The M30d Automatic delivers a refined and comfortable driving experience. The abundant torque from the diesel engine provides strong off-the-line acceleration and effortless overtaking. While not as overtly sporty as some of its gasoline-powered siblings, the M30d offers a composed and stable ride. The seven-speed automatic transmission contributes to this smoothness, although it can sometimes feel slightly hesitant during quick downshifts. Compared to the higher-output M37 (with its 3.7-liter V6), the M30d prioritizes fuel efficiency and low-end torque over outright horsepower. The gear ratios are optimized for cruising, making it an excellent long-distance companion. The rear-wheel-drive configuration provides a balanced feel, although it lacks the all-wheel-drive security offered on some other M models.
Equipment & Trim Levels
The M30d typically came well-equipped, reflecting its luxury positioning. Standard features often included leather upholstery, power-adjustable front seats with memory function, a premium audio system, dual-zone automatic climate control, and a navigation system. Infiniti’s signature lane departure warning and intelligent cruise control systems were also frequently included. Optional extras could include a panoramic sunroof, upgraded leather trim, and a rear-seat entertainment system. Trim levels varied by market, but generally, the M30d represented a mid-to-high level of specification within the M range.
Chassis & Braking
The Y51 M-series utilizes a double wishbone front suspension and an independent multi-link rear suspension, providing a comfortable and controlled ride. A stabilizer bar is fitted to both axles to reduce body roll during cornering. The braking system consists of ventilated discs on all four wheels, with larger discs at the front (355mm) compared to the rear (350mm). Anti-lock brakes (ABS) and electronic brakeforce distribution (EBD) are standard features. The steering is a rack-and-pinion system with electric power assistance, offering a responsive and precise feel.
Market Reception & Comparison
The Infiniti M30d was generally well-received by automotive critics, who praised its refined engine, comfortable ride, and generous equipment levels. However, some reviewers noted that the interior design, while luxurious, lacked the visual flair of some German competitors. Fuel economy was a strong point, consistently exceeding that of comparable gasoline-powered models. Compared to the M37, the M30d appealed to buyers prioritizing efficiency and low-running costs. Against rivals like the BMW 530d and Audi A6 3.0 TDI, the M30d offered a competitive package, often at a slightly lower price point.
Legacy
The V9X engine, while generally reliable, can be susceptible to issues with the diesel particulate filter (DPF) if not driven on longer journeys regularly. The Jatco seven-speed automatic transmission is also known to be durable, but requires regular fluid changes to maintain optimal performance. In the used car market, the M30d represents a good value proposition for buyers seeking a comfortable and efficient luxury sedan. Its relatively low running costs and strong performance make it an attractive alternative to more expensive German rivals. However, potential buyers should be aware of the potential DPF issues and ensure the vehicle has been properly maintained.
