Introduction
The 2015 BMW 640i Gran Coupe M Sport bridges the gap between executive luxury and athletic performance. While traditional sedans prioritize passenger space and two-door coupes focus strictly on styling, this four-door fastback merges sleek proportions with everyday usability. Beneath its striking exterior lies a powertrain engineered for balanced daily driving and responsive power delivery.
Buyers eyeing this generation often weigh its luxury pedigree against maintenance realities, fuel economy, and long-term durability. We'll examine the actual performance metrics, interior layout, common mechanical pitfalls, and ownership costs to see how this executive cruiser holds up.
Performance and Engine Specifications
At the core of the 640i Gran Coupe M Sport is BMW's N55 3.0-liter turbocharged inline-six engine. Pumping out 320 horsepower and 330 lb-ft of torque starting at a low 1,300 RPM, it provides immediate throttle response without the turbo lag typical of older forced-induction setups. Power routes through an eight-speed ZF automatic transmission to the rear wheels, allowing a 0 to 60 mph sprint in roughly 5.1 seconds.
Unlike the V8-powered 650i, which gained a reputation for higher thermal stress and oil consumption issues, the inline-six N55 configuration offers a more balanced weight distribution over the front axle. This translates to sharper turn-in and agile handling on winding roads. If you want more about the history of this, Associated Press provides an excellent summary.
Drive Modes and Dynamics
The car features a driving dynamics control switch on the center console, letting you toggle between Eco Pro, Comfort, Sport, and Sport+ modes. Each setting recalibrates throttle mapping, transmission shift points, and steering weight.
- Comfort Mode: Relaxes damper stiffness and softens throttle inputs, making rough city asphalt manageable.
- Sport Mode: Tightens steering feedback, holds gears longer, and firms up the adaptive suspension.
- Sport+ Mode: Disables lower traction control thresholds, sharpens shifts, and unleashes the full capability of the chassis.
Design, Exterior, and M Sport Enhancements
The M Sport package alters the visual presence of the standard 6 Series Gran Coupe. Up front, you get an aggressive aerodynamic bumper with larger air intakes, side skirt extensions, and high-gloss shadowline exterior trim. The low-slung roofline and frameless doors give it a coupe silhouette, though it retains a wheelbase stretched nearly 4.5 inches beyond the standard two-door coupe to accommodate rear passengers.
Standard wheels on the M Sport package are 19-inch light-alloy star-spoke style rims, though many models feature upgraded 20-inch M double-spoke wheels wrapped in staggered performance rubber.
Interior Comfort and Technology
Inside, the cabin wraps the driver in premium materials, including Dakota leather upholstery, an anthracite headliner, and an M-specific leather steering wheel. The dashboard tilts slightly toward the driver, housing the iDrive infotainment display controlled by the central rotary dial.
Space in the front row is generous, but the sloping roofline and prominent central tunnel compromise rear passenger accommodations. While marketed as a five-seater, the rear middle seat is best reserved for short trips due to the bulky console and footwell layout. Cargo capacity sits at 13 cubic feet in the trunk, which handles golf bags or weekend luggage easily, though the rear seats do not fold flat in a standard pass-through configuration.
Ownership Realities and Common Issues
Buying a pre-owned luxury car requires understanding common maintenance items. The N55 engine is generally regarded as one of BMW's more reliable modern turbocharged powerplants, but it has specific trouble spots you need to watch for:
- Oil Filter Housing Gasket (OFHG): Prone to degrading and leaking oil down the front of the engine block, which can contaminate the serpentine belt and cause it to snap.
- Water Pump and Thermostat: These electronic water pumps typically fail between 60,000 and 90,000 miles. Proactive replacement prevents overheating.
- Charge Pipe Failure: The factory plastic charge pipe connecting the intercooler to the throttle body cracks under high boost, especially if tuned. Upgrading to an aftermarket aluminum replacement is a common preventive fix.
- Vanos Solenoids: Regular oil changes every 5,000 to 7,000 miles are critical to prevent varnish buildup on the variable valve timing solenoids.
For official manufacturer specifications and maintenance intervals, consult BMW USA. To research vehicle history and safety ratings during your search, check the National Highway Traffic Safety Administration.
Frequently Asked Questions
Is the 2015 BMW 640i Gran Coupe reliable?
Yes, compared to its V8 sibling (the 650i), the 640i's inline-six N55 engine is notably more reliable and less prone to catastrophic mechanical failure. However, it still requires diligent maintenance and premium fluids.
What is the real-world fuel economy?
Drivers typically average around 20 mpg in mixed city and highway driving, with highway figures reaching up to 29 mpg if driven conservatively in Eco Pro mode.
Does the M Sport package add extra horsepower?
No, the M Sport package is purely cosmetic and aerodynamic. It adds styling bumpers, sport seats, an M steering wheel, and upgraded wheels, but engine output remains identical to non-M Sport models.
How does rear passenger space compare to a 5 Series?
Despite sharing a platform architecture, the Gran Coupe has less headroom in the rear because of its sloping roofline, making the 5 Series a more practical choice for tall rear passengers.
