The BlueTec diesel engine is one of the stars of the lineup, as it manages more low-rpm torque--what matters for towing and full loads--than the GL 450 V8. Yet with EPA fuel economy ratings of 19 mpg city, 26 highway, this 7-passenger SUV is just as efficient as some much smaller crossovers. It's also 50-state certified, thanks to a system that injects a solution called AdBlue into the exhaust flow, cleaning up emissions. V8 models are a bit smoother and higher revving and these stoutly constructed V8 engines have a thicker new piston-crown design to handle the extra power. Both have direct injection, refined variable valve timing and twin turbochargers for a wide torque curve and fuel economy that's more typical for large V8 SUVs (14/19 mpg for the GL 450, or 13/18 for the GL 550).
Throughout the lineup the GL-Class has a 7-speed automatic transmission that teams with 4Matic 4-wheel drive and has been optimized for better mileage and durability plus responsiveness and refinement. In each case, it makes the most of engine power for passing or strong acceleration, yet it's smooth and unobtrusive during relaxed driving.
Just as on the outside, where the redesigned GL models aren't quite as boxy and truck-like as last year--they're a little more sculpted instead--the GL has evolved to be more luxurious and carlike than ever inside. The front seats in the Mercedes-Benz GL can be equipped with heating, ventilation and multi-contour functions that not only massage you but give you added support in corners. The GL-Class has second-row seats that are adult-sized and have a power-operated access feature to make it easier to reach the third row, which is split 50/50 and can be flipped forward--as can the second row.
A height-adjustable Airmatic suspension system is included in all GL models and it helps soak up road shocks while keeping the body level. Electromechanical rack-and-pinion steering with speed-dependent power assist brings a confident feel both at high speeds and trail speeds. Meanwhile, the GL retains its truck-caliber abilities, with excellent towing capability as well as off-road chops--when you check the right option boxes. With the On & Offroad Package, the GL-Class gets additional underfloor paneling, a dual-range transmission, and underrun protection for the engine, as well as a version of the Airmatic suspension that allows more ground clearance--up to 12 inches, with a water-fording depth of 23.6 inches.
The latest version of Mercedes-Benz's COMAND screen-based interface is part of the instrument panel of every new GL-Class. COMAND manages entertainment and includes HD Radio, Bluetooth hands-free calling and Bluetooth audio streaming, while an iPod interface, satellite radio and enhanced voice control are available. A hard-drive navigation system is optional and it can incorporate real-time Sirius traffic information and Zagat restaurant ratings. A rear-seat entertainment system is also optional and includes two 8-inch screens plus wireless headphones and a DVD player, while the top entertainment possibility is a harman/kardon Logic7 surround-sound system with 830 watts and 14 speakers.
The GL-Class is also loaded with active-safety features. Attention Assist looks for signs that the driver may be drowsy, while Collision Prevention Assist warns the driver of a possible collision and primes the brakes. Active Parking Assist is also available and helps automatically steer the vehicle into a spot while the driver controls acceleration and braking, while keeping under 7 mph. Other optional active-safety features include Active Lane Keeping Assist, an Active Curve System and a 360-degree Surround View camera system. A Panorama Roof is also available. Many of these options are grouped in packages and two Premium Packages add hard-drive navigation, memory front seats, interior ambient lighting, illuminated door sills and audio upgrades. Three-zone climate control, heated rear seats, a heated steering wheel and stylish real woodgrain trims are also on the options list.
Later in the model year--though also as a 2013 model--a high-performance Mercedes-Benz GL63 AMG model will join the lineup, including a twin-turbocharged, hand-built V8 engine making 550 horsepower and 560 pound-feet of torque.