The Infiniti QX56 5.6 V8 AWD Automatic, produced from 2004 to 2007, represents the first generation of Infiniti’s full-size luxury SUV. Positioned as a competitor to the Cadillac Escalade, Lincoln Navigator, and Lexus LX, the QX56 aimed to deliver a blend of American-style spaciousness, robust V8 power, and a more refined driving experience than some of its domestic rivals. Built on the Nissan F-Alpha platform (shared with the Nissan Armada and Titan), the QX56 was Infiniti’s entry into the burgeoning luxury SUV segment, offering a standard third-row seat and available four-wheel drive. This particular configuration, featuring the 5.6-liter V8 engine paired with a five-speed automatic transmission and all-wheel drive, was the sole powertrain option throughout its production run.
Technical Specifications
| Brand | Infiniti |
| Model | QX56 |
| Generation | QX56 |
| Type (Engine) | 5.6 V8 (320 Hp) AWD Automatic |
| Start of production | 2004 |
| End of production | 2007 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | SUV |
| Seats | 7-8 |
| Doors | 5 |
| Fuel consumption (urban) | 18.1 l/100 km (13 US mpg, 15.6 UK mpg, 5.5 km/l) |
| Fuel consumption (extra urban) | 12.4 l/100 km (19 US mpg, 22.8 UK mpg, 8.1 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.2 sec |
| Acceleration 0 – 62 mph | 7.2 sec |
| Acceleration 0 – 60 mph | 6.8 sec |
| Maximum speed | 180 km/h (111.85 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 8.2 kg/Hp, 122.4 Hp/tonne |
| Weight-to-torque ratio | 4.9 kg/Nm, 202.3 Nm/tonne |
| Power | 320 Hp @ 4900 rpm |
| Power per litre | 57.6 Hp/l |
| Torque | 529 Nm @ 3600 rpm (390.17 lb.-ft. @ 3600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | VK56DE |
| Engine displacement | 5552 cm3 (338.8 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 98 mm (3.86 in.) |
| Piston Stroke | 92 mm (3.62 in.) |
| Compression ratio | 9.8:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | DOHC |
| Engine oil capacity | 6.2 l (6.55 US qt | 5.46 UK qt) |
| Coolant capacity | 14.4 l (15.22 US qt | 12.67 UK qt) |
| Kerb Weight | 2615 kg (5765.09 lbs.) |
| Max. weight | 3175 kg (6999.68 lbs.) |
| Max load | 560 kg (1234.59 lbs.) |
| Trunk (boot) space – minimum | 1733 l (61.2 cu. ft.) |
| Fuel tank capacity | 106 l (28 US gal | 23.32 UK gal) |
| Length | 5250 mm (206.69 in.) |
| Width | 2000 mm (78.74 in.) |
| Height | 1970 mm (77.56 in.) |
| Wheelbase | 3130 mm (123.23 in.) |
| Front track | 1715 mm (67.52 in.) |
| Rear (Back) track | 1715 mm (67.52 in.) |
| Ride height (ground clearance) | 270 mm (10.63 in.) |
| Drivetrain Architecture | All wheel drive (4×4) |
| Number of gears | 5 |
| Gearbox type | Automatic transmission |
| Front suspension | Double wishbone |
| Rear suspension | Double wishbone |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 265/70 R18 |
| Wheel rims size | 8J x 18 |
Powertrain & Engine Architecture
The heart of the QX56 is the VK56DE 5.6-liter V8 engine. This engine, a member of Nissan’s VK engine family, is a naturally aspirated, 32-valve DOHC powerplant. It utilizes a cast iron block with aluminum cylinder heads, and employs multi-port fuel injection. The VK56DE is known for its smooth power delivery and relatively robust construction. The engine produces 320 horsepower at 4900 rpm and 529 Nm (390 lb-ft) of torque at 3600 rpm. The five-speed automatic transmission, designated as the 5R110W, is a heavy-duty unit designed to handle the engine’s substantial torque output. This transmission features electronic controls and offers a relatively smooth, albeit not particularly sporty, shifting experience. The all-wheel-drive system is a part-time system, typically operating in rear-wheel drive until wheel slip is detected, at which point it engages the front axle.
Driving Characteristics
The QX56 5.6L Automatic delivers a comfortable and capable driving experience, prioritizing ride quality over outright performance. While the 320 horsepower provides adequate acceleration – 0-60 mph in around 6.8 seconds – it doesn’t feel particularly quick compared to some of its European competitors. The five-speed automatic transmission, while reliable, lacks the responsiveness of more modern transmissions with a greater number of gears. The gear ratios are tuned for cruising and towing, rather than spirited driving. The all-wheel-drive system provides enhanced traction in inclement weather, but the QX56 is not designed for serious off-roading. The vehicle’s substantial weight (over 5700 lbs) is noticeable in cornering, resulting in some body roll.
Equipment & Trim Levels
The QX56 came reasonably well-equipped as standard. Typical features included leather upholstery, tri-zone automatic climate control, a Bose premium sound system, power-adjustable front seats with memory function, and a rear air conditioning system. Optional extras included a navigation system, rear seat entertainment system with DVD player, power-folding third-row seats, and a sunroof. The interior design was generally considered luxurious for its time, with a focus on wood trim and comfortable seating. The QX56 offered seating for seven or eight passengers, depending on whether the second row featured captain’s chairs or a bench seat.
Chassis & Braking
The QX56 utilizes a body-on-frame construction, which contributes to its robust feel and towing capacity. The suspension consists of independent double wishbones at both the front and rear. The braking system features ventilated disc brakes at all four corners, along with ABS (Anti-lock Braking System). Rear disc brakes were standard, a feature not always found in this class of vehicle at the time. The steering is a rack-and-pinion system, providing reasonably precise steering feel, although it lacks the feedback of more performance-oriented SUVs.
Market Reception & Comparison
The Infiniti QX56 was generally well-received by critics, who praised its spacious interior, comfortable ride, and powerful V8 engine. However, some reviewers noted its relatively poor fuel economy (13-19 mpg) and its lack of sporty handling. Compared to the 1.8L four-cylinder models, the QX56 offered a vastly superior driving experience, but at a significant cost in terms of fuel consumption. The QX56’s reliability was generally considered good, although some owners reported issues with the cooling system and the automatic transmission over the long term. Compared to the Cadillac Escalade and Lincoln Navigator, the QX56 offered a more refined driving experience and a more upscale interior, but it lacked the brand cachet of those American icons.
Legacy
The first-generation Infiniti QX56 established Infiniti as a serious player in the full-size luxury SUV segment. While the VK56DE engine proved to be generally reliable, preventative maintenance, particularly regarding the cooling system, is crucial for long-term durability. On the used car market, the QX56 remains a relatively affordable option for those seeking a spacious, comfortable, and capable SUV. However, potential buyers should be aware of the vehicle’s relatively poor fuel economy and the potential for age-related maintenance issues. The QX56 paved the way for subsequent generations of Infiniti’s flagship SUV, which have continued to evolve and refine the formula of luxury, space, and capability.
