Used 2010 Mercedes-BenzGL-Class GL450 4MATIC 4.6

This review was written in November 2008 about the 2009 Mercedes-Benz GL-Class. Little of substance has changed with this year's model. To see what's new for 2010, click here, or check out a side-by-side comparison of the two model years.

With a 23-mpg diesel version now available in all 50 states, the Mercedes-Benz GL-Class is a more viable option for SUV-needing families — though the appeal of a $60,000-plus four-wheeler seems limited in today's economy. Even if you are in the market, the GL remains a debatable choice: stylish on the outside and elegant within, but hamstrung by spotty reliability and a drivetrain as indecisive as the North Carolina electorate.

Still, that's more praise than I can give last year's model, whose review serves as the basis for this update; its dated navigation system was onerous to sort through, but it's been vastly improved for 2009. The SUV also gets more high-tech safety features, though they might just be gilding the lily on a model that already had nine standard airbags and an electronic stability system.

Trim levels include the diesel GL320 Bluetec and gasoline GL450 and GL550; click here to compare them or here to compare the whole group to its '08 equivalents. I drove a 2009 GL320 Bluetec, and I've also driven a 2008 GL550.

Muscular Moves, Eventually
The turbo-diesel GL320 Bluetec has additional exhaust treatments to cut soot and nitrogen oxide emissions — technology last year's diesel GL320 CDI lacked, which is why California and several Northeastern states wouldn't sell it. The new diesel six-cylinder performs like most diesels of its kind: burly and full of grunt early on, but loathe to produce much more power when you rev high. Indeed, it has more torque than the V-8 GL550, and it puts it all on the plate at just 1,400 rpm. Accessing that power is harder than it sounds, though, as the Bluetec is plagued by a bad case of accelerator lag, and its seven-speed automatic isn't particularly responsive. Put together, it takes a patient right foot to nurse the proper acceleration out of the beast; prod the pedal hard, and the response is tepid at first, but after a second or so it's probably more than you asked for.

Though I didn't drive the V-8 GL450, Mercedes quotes a 7.4-second zero-to-60 mph time, which is impressive for something that weighs nearly as much as a Chevy Tahoe. The GL550 is the lineup's hardest hitter: It uses Mercedes' 5.5-liter V-8, a thoroughly modern engine shared with some of the brand's best models. The engine's wide power band propels the GL to freeway speeds with ease, and the automatic transmission feels better groomed for this application, downshifting two or three gears at a time for quick, confident bursts of power.

Alas, accelerator lag still rears its head. It isn't apparent during stop-and-go driving, but a sudden call for power — escaping a slow-moving freeway lane, for example — is sometimes met with a lazy response. I try to tolerate some lag, as it's often a byproduct of the electronic throttles that most cars, including the GL, employ these days. What frustrates me is inconsistent response, and that's what the GL exhibits. Sometimes the gas pedal is virtually lag-free, while other times it takes half a second or longer to summon the appropriate oomph.

Antilock brakes with discs at all wheels are standard. The pedal delivers strong response, but it's a bit touchy when you lift back off, so smooth stops may take practice.

Running the Numbers
Thanks to diesel engines' higher efficiency, the Bluetec achieves nearly the same EPA ratings as a Cadillac Escalade Hybrid. The figures are 27 percent better overall than those of the gas GL450, though the latter model has a V-8 versus the Bluetec's V-6, so this isn't necessarily an apples-to-apples comparison. This year's Bluetec is also 1 mpg worse than last year's GL320 CDI. Mercedes spokesman Rob Moran said that's due to this year's larger wheels — 20-inchers versus 18s, which introduce "quite a bit more rolling resistance." In real-world driving, Moran claims the differences are slighter than the EPA ratings suggest. Here's how the engines compare:

Ride & Handling
The GL has a unibody frame — rare among full-size SUVs — and its four-wheel-independent air suspension swaps traditional coil springs for inflatable air bladders. Ride height can be varied to enhance high-speed stability or offroad ground clearance. An optional adaptive suspension constantly adjusts ride stiffness as conditions require, with Sport and Comfort modes that yield, respectively, stiffer or softer response. There's also an Auto mode that calibrates the settings somewhere between those two based on conditions. Both the GL550 and GL320 I drove had the system, and I'll attest that Sport mode resists body roll marginally better than Comfort, but the differences are slight.

More consequential are the GL550's 21-inch alloy wheels and sporty P295/40R21 tires, which combine with unusually precise steering to make curvy roads a bit of fun. There's still enough power assist at lower speeds for tight parking-lot maneuvers, though at times I found lumpy pockets of resistance while navigating our downtown parking garage. That's a noticeable difference from the steering wheel's confident, planted feeling on the highway.

Naturally, fun comes at a price. The GL550's advanced suspension can't make up for the brittle ride quality of its thin 40-series tires. You'll hear and feel every highway expansion joint, and potholes and speed bumps become a jarring, noisy experience. Most annoying was the abundance of suspension reverberation I felt around Chicago's roughed-up streets: No matter what setting I had the suspension on, major bumps sent palpable motions through the entire chassis for a half-second or more.

On smoother roads — that's you, Governator State — the ride feels more agreeable. Tire noise is still noticeable, but wind noise is minimal and the engine is nearly silent. The GL320's 20-inchers and P275/50R20s yield better ride comfort still, though the GL450, which has 18-inch wheels and P265/60R18 tires, is probably the most forgiving of the three.

At 39.7 feet, the GL's turning circle is competitive with its peers.

Exterior & Styling
Particularly from the rear, the GL's appearance looks a bit like Mercedes' original M-Class — so much so that a passenger walked up to an older M thinking it was the GL. The GL550's 21-inch wheels, oversized grille and rubber-studded running boards give it a look similar to that of Mercedes' AMG performance cars — perhaps that was the intention, given there is no AMG GL-Class — and should secure the car a front-row spot at most valet stands. Lesser models can be dressed to match, albeit with a smaller grille.

Less-expensive GLs have 18- or 19-inch wheels. An optional offroad package raises the air suspension to yield 12 inches of ground clearance, 2 inches higher than a Hummer H2's. The package also includes a two-speed transfer case and locking center and rear differentials.

Cabin Quality
If the cockpit in a Cadillac Escalade or Infiniti QX56 feels like a roomy lounge, the GL550's cabin is eminently more carlike. Don't expect massive armrests and a tall dashboard — rather, the wraparound dash and narrower seats could pass for those in a luxury sedan. Quality is good: Upper portions of the dashboard come wrapped in leather, and wood and chrome inlays effectively offset the lower panels. Nearly every surface is soft to the touch, including areas the driver's and front passenger's knees might knock against. Fit and finish is respectable, save an unsightly gap around the glove compartment. A more ergonomic steering wheel has replaced last year's ill-fitted one, whose audio controls were too easy to press by accident.

The center controls look and feel high-quality, and it's nice to see Mercedes has stuck with black plastic where other carmakers have painted theirs a tacky-looking silver. The navigation system has also been enormously improved over its predecessor, with the latest rendition of Mercedes' Comand interface. Gone are last year's tacky graphics and annoying smart-key interface; now there's a handy directional keypad with shortcut keys to zoom in or out or go back a screen. The graphics, too, are first-rate.

Blind-spot visibility is generally good, but most Cars.com staffers who drove the GL thought the tiny side mirrors were a joke.

Seating & Cargo
The front seats have a litany of power adjustments, including optional side-bolster adjustments. Even with the bolsters and lumbar support dialed all the way back, I found the seats stiff. That's typical in German cars, but in a large SUV I prefer cushier seats. The GL has the kind of seats that hold you in place during spirited driving; expert road manners notwithstanding, I'm not sure many GL-Class drivers are going to carve corners.

I compared seating in a GL-Class, QX56, Escalade and Lexus LX 570 at an auto show, and the front seats of all three competitors suited me better than the GL's. Second-row space in the GL seems on par with the competition — I'm about 6 feet tall, and I had no complaints — but it's the third row that shines. Legroom and headroom in the GL are leagues better than in the others, and the GL's seats sit high enough that passengers aren't staring at their knees. The Lincoln Navigator is perhaps the only competitor that has as much third-row room. As craftsmanship goes, there is no competition: The GL's third row boasts reading lights, overhead A/C vents, a fixed skylight and leather-wrapped armrests. It puts the other SUVs' third-row décor to shame.

All trim levels have a power-folding 50/50-split third row. It folds more or less flat, as does the second row, and the resulting load floor is free of any major gaps. Maximum cargo volume is 83.3 cubic feet, which considerably trails some of the GL's boxiest competitors.

Safety & Reliability
As of this writing, the Insurance Institute for Highway Safety had not yet crash-tested the GL-Class. The nine standard airbags include three-row side curtain airbags, a driver's knee airbag and seat-mounted side-impact airbags for the first and second rows. Active head restraints, all-disc antilock brakes, traction control and an electronic stability system are also standard.

Newly standard for 2009 is Mercedes' Pre-Safe system, which uses sensors in the braking and stability systems to intuit a likely collision. It then cinches up the seat belts, closes any open windows to minimize intrusions and adjusts the seats for maximum airbag effectiveness. Though in most cases there won't be enough time to fully perform those actions, Mercedes' Moran said, "the thinking there is that anything is better than nothing ... even if the window was down halfway and it got up three-quarters of the way, it would be better."

With Latch child-seat anchors for the outboard second- and third-row seats, don't be surprised if you're drafted to schlep the entire neighborhood's tots to day care. The second row has top-tether anchors for all three seats, and they're conveniently mounted midway down the back of the seats. Parents should note that all the anchors have removable plastic covers. They're a pain in the neck to pry off, so here's betting you'll leave them off — and lose them.

Poor reliability continues to be the GL's biggest drawback. In its first two years on the market, the SUV earned the worst possible score, Much Worse Than Average, from Consumer Reports. The publication cited body hardware as the GL's biggest trouble spot. I'd be more concerned if large luxury SUVs weren't generally such a reliability letdown; the Escalade earned dismal reliability scores, and although Consumer Reports didn't have sufficient data to rate the Range Rover in 2008, the SUV got poor ratings in prior years. The QX56 and Navigator are relative bright spots, with reliability ratings of Average. The recently redesigned LX 570 hasn't been on the market long enough to gauge.

Features & Pricing
Excluding the destination charge, the GL320 Bluetec starts at $58,200, while the GL450 starts at $59,200. Both represent $3,000-plus increases over last year's prices, though larger standard wheels on the Bluetec and additional standard features — among them a six-CD changer and a moonroof — mitigate this a bit. Other standard features include four-wheel drive, faux leather upholstery, dual-zone automatic climate control, a fixed third-row skylight and heated power front seats. The GL550 hikes the price considerably ($81,300) but comes standard with leather upholstery, keyless access with push-button start, a backup camera, heated second-row seats, Harman Kardon audio, xenon headlights and a navigation system. Many of those features are optional on lesser trims.

GL550 options include a rear-seat DVD system, upgraded leather and ventilated front seats. Fully loaded, the GL-Class tops out around $87,000.

GL-Class in the Market
The GL's price spread gives it a wide range of competitors. At the low end it competes with Infiniti and Lincoln, and at the high end there's Lexus and Land Rover. Though sales are down these days, the GL hasn't tanked as fast as the rest of Mercedes' lineup, which is tracking about even with the auto industry's general decline.

The GL is doing better than it should, and I can see why: The Bluetec's national availability coincides with a dramatic decline in gas prices, which should go a long way toward sweetening the prospect of buying a large luxury SUV. Indeed, there are enough strengths to make the GL a worthy steed for some, but until Mercedes irons out the drivetrain kinks — and improves the reliability — I can't recommend it for everyone