Getting Deliciously Dirty With Clean Diesel

Back in July, our man Bowman got his first chance to drive the new Mercedes M-Class in the wilds of Montana, and he came away particularly impressed by the ML350 BlueTEC 4Matic. It's great news that this updated diesel powertrain is coming to the United States in November, but in Montana, we missed out on the new-generation On&Offroad Package and innovative Active Curve System.

Fortunately, we were recently afforded the chance to test all of this goodness over a small paved circuit in Austria, as well as up and down a truly hellacious off-road course. By the end of the day, we were convinced that this ML350 diesel 4x4 thus equipped can finally take it to a similarly optioned BMW X5 or Porsche Cayenne. And, as Mercedes Germany tells us, North American buyers will at long last get a crack at this On&Offroad harder-core package for 2013. Are they at risk of messing with the winning on-road recipe that has made the M-Class the world's best-selling premium SUV, with over 1.2 million sold?

First off, we just have to say it: We like the looks of this new-for-2012 model a whole lot more than the aging clumpiness of the first two generations. The profile could be more balanced visually, but from every other angle, the new ML is a spot-on looker in what is frankly an aesthetically compromised segment.

2012 Mercedes ML350 BlueTEC side view2012 Mercedes ML350 BlueTEC front view2012 Mercedes ML350 BlueTEC rear view

We first climbed behind the wheel of an ML350 BlueTEC 4Matic without the On&OffRoad package (above in silver), and we can echo what has already been said about this 3.0-liter V6 BlueTEC diesel: It's at the top of its game, and M-Class' revamped air suspension is much more satisfying when either normal cush or sportier seriousness is called for. While 17-inch tires are standard, the optional (and less noisy) 255/50 R19 W Continental ContiSportContact Tires of are just the right blend for asphalt action. The real new goodness, however, starts when the available Active Curve System is put to work. Active front and rear anti-roll bars actuate instant-to-instant to compensate for lateral g forces, and the added confidence from behind the well-designed steering wheel is clear. As you might imagine, this technology is particularly noticeable when hustling this 4,795-pound bruiser hard through the corners. Off-road, and when selected on road, the ACS can remain "open" – disengaged – to allow for more live axle feel and articulation. Engage it, though, and kinks get straightened out nicely.

As to the On&OffRoad Package we finally got to test in a brown-colored ML350 BlueTEC 4Matic, there are six different ride and drivetrain settings. The one most used is certainly Auto, which capably handles almost any daily drive situations. Then there are Sport, Winter and Trailer modes by turning the console knob to the left, and two off-road modes by turning to the right. The first off-road mode is milder and does not involve the low range of gears, though the suspension does raise slightly. The most extreme off-road setting swells ground clearance to an impressive 11.2 inches (max wading depth is nearly 24 inches and there's a skid plate to avoid disembowelment), and there's a two-stage transfer case and low range lock that helped us climb at will. The revamped COMAND on-board display details all of the system's parameters, showing comfort levels, percentages of angle and traction distribution left-to-right, and it turns the engaged low-range differential red.

2012 Mercedes ML350 BlueTEC center gauge display2012 Mercedes ML350 BlueTEC off-road display2012 Mercedes ML350 BlueTEC ride height controls2012 Mercedes ML350 BlueTEC drive mode controls

We tend to think of the M-Class plying suburban parking lots and at worst plying rutted dirt parking lots at the local apple orchard or yard sale, but Benz officials tell us that added off-road capability was a frequent request from likely customers. The previous system, the Europe-only Off-Road Pro Engineering package, only involved a single on-road setting and one detent for the rough stuff, and the whole setup was simply not up to snuff versus the competition.

During our industrial-strength off-road sessions with the On&OffRoad Package-equipped ML350 BlueTEC 4Matic, we did things that no no sane person would have ever tried in a previous-generation ML. Besides proving highly capable when attacking a 45-degree climb consisting of loose dirt and rocks (with a full stop-and-go mid-climb to highlight the hill-hold function that works with the seven-speed dual-clutch), we pulled off almost every textbook Jeep Wrangler trick. Then came the 80-degree descent on rough pavement using the well-calibrated Downhill Speed Regulation (DSR). The Dunlop M+S GrandTrek tires – same dimensions as the on-road Contis but with gnarlier tread – proved up to the task. Our vertiginous descent was actually more of a controlled skid, but nonetheless, the 4Matic system and traction control software managed gravity well while we touched nary a pedal. If we were really going to treat our ML this way on a normal basis, however, a burlier set of treads would be a better fit. But who is kidding whom?

2012 Mercedes ML350 BlueTEC w/ On&Offroad Package2012 Mercedes ML350 BlueTEC w/ On&Offroad Package2012 Mercedes ML350 BlueTEC w/ On&Offroad Package2012 Mercedes ML350 BlueTEC w/ On&Offroad Package

As we've said before, more than the 240 horsepower on hand, the 455 pound-feet of torque (available from 1,600 rpm) offered by the turbocharged and direct-injected 3.0-liter V6 diesel is the true star here. Deploying the throttle judiciously in any off-road condition (or on) made for effortless work, and when the time came for acceleration, 7.2 seconds for this big boy to reach 60 miles per hour isn't exactly slow. All the while, the AdBlue- and particulate filter-aided diesel drivetrain returns an EPA-rated highway best 27 miles per gallon and pollutes with 25 percent less CO2 emissions than the last ML350.

This is a package that finally gets us authentically geeked about the ML SUV phenomenon for the first time in its long and successful life. Its on-road dynamics and noise isolation have significantly improved, and it's now possible to consider taking the ML350 BlueTEC 4Matic where formerly we would have opted by reflex for a trail-rated Jeep Grand Cherokee – this makes some sense, as the two share a fair bit of DNA.

2012 Mercedes ML350 BlueTEC w/ On&Offroad Package

We're certain that in the hands of most owners, M-Class models will remain caged on flat asphalt, hauling kids and cappuccinos from sunup to sundown. From where we sit, it's a shame that most M-Class drivers will never know the true mettle of their daily drivers, but the M's well-rounded nature means that they won't be penalized by a stiff-legged ride, inhospitable noise levels or loathsome handling – all historic hallmarks of genuinely capable off-roaders.

This, friends, is progress.