Mercedes-Benz ML320 CDI 2006

OVERVIEW
Aussies have taken to luxury 4WDs in the last half-decade or so as keenly as they do to cold beer on a hot day. Mercedes, thinking more about the USA's huge thirst for SUVs rather than a piddling Australian market, was instrumental in starting this trend when its first-generation ML was released back in late 1998.

But the initial popularity of the butch Benz soon waned as newer and better alternatives arrived from rival manufacturers. Fit and finish issues didn't help the ML's cause either, nor did the fact that its chassis and suspension appeared to be benchmarked down to American, not up to European standards.

But that's all history now as Mercedes' second-generation ML is a completely clean-sheet design that's new from the tyre treads to the roof rails. Mercedes even junked the separate chassis of the original ML for monocoque construction with the new vehicle.

Our first taste of this new, second-generation ML came via the impressive ML 350 and ML 500 petrol models that debuted earlier this year. Now Mercedes has released what is arguably the best model in the new ML line-up, the 320 CDI turbo diesel.

FEATURES
Don't be fooled by the '320' designation, the ML 320 CDI is, in fact, powered by a 3.0-litre, not a 3.2-litre engine. And, like the two petrol engines in the new ML range, this high-tech turbo-diesel is backed by Mercedes' new seven-speed automatic transmission, the only transmission available right across the model range.

The 320 CDI starts at $82,900, $3000 more than the ML 350 (3.5-litre petrol V6) but $34,000 cheaper than the highly specified ML 500 with its 5.0-litre V8.

The CDI's equipment level is on a par with the ML 350 which means fabric/faux-leather seats, dual-zone climate control, cruise control, six-CD sound, 17-inch alloys, front and rear parking sensors, and rain-sensing wipers among a host of other features.

And, as is the way of German luxury car-makers, there's a list of options that runs to several pages, some of which are grouped in various option packages while others stand alone.

The option packages include the usual Merc add-ons like the Luxury Package (leather trim etc – $8000) and Sports Package (19-inch alloys, sports seats etc – $9980), but more interesting is the Off-Road Pro Engineering Package. For $10, 150 this buys height-adjustable air suspension, low-range gearing, lockable centre and rear electronic clutch-pack differentials, and extra under-body protection. In fact all the sort of stuff you need for a good day out in the bush ... almost.

Like other MLs, the CDI doesn't come with a factory-fitted full-size spare, a massive oversight that's been corrected by MB Australia with a retro-fit full-size spare that comes at the expense of less luggage space via a raised floor in the cargo area.

COMFORT
The ML's cabin is roomy with a class-leading back seat that's generous enough to accommodate three full-size adults without the usual compromises in hip or shoulder room.

The driver and passenger seats are the usual Mercedes fare in as much as they are quite firm, but still very comfortable. As standard the driver's seat has a mixture of manual and electric adjustments and the steering wheel is also manually adjustable for reach and tilt. If you're not happy with any of this, then there's no shortage of seating options like heated seats, sports seats, or multi-contoured backrests.

SAFETY
As you'd expect, the new M-Class comes fully loaded with both passive and active safety equipment. It's also no surprise that it has already received a five-star safety rating in the NCAP (USA) crash tests.

Standard passive safety gear includes two-stage driver and passenger airbags, front and rear side airbags and window airbags. Helping you avoid an accident in the first place are ABS brakes with brake-assist, and electronic traction and stability control.

The New M-Class also has what Mercedes calls Pre-Safe, a system that 'prepares' vehicle for an accident if it detects (via the chassis electronics) that one is imminent. It does this by pulling the driver and front passenger seat belts taut, moving the cushion and backrest of the electrically adjustable front passenger seat (if fitted) to more favourable positions, and by closing the sunroof (if fitted), if there is a risk of the vehicle rolling over.

MECHANICAL
Those with an eye on recent automotive developments could hardly have failed to notice the great advances being made in diesel engines, particularly those coming out of Europe.

At the heart of the 320 CDI is the most sophisticated diesel yet to appear in a passenger vehicle in Australia. It's a quad-cam 24-valve turbocharged and intercooled V6 that features Bosch's third-generation, high-pressure (1600+bar) common-rail fuel-injection system that uses fast-switching piezo-crystal, rather than electro-magnetic injectors.

This engine is clean enough to meet Euro 4 emissions which means it meets local exhaust-emission ADRs that won't even come into place for a couple of years.

This engine also makes 510Nm peak torque, 50Nm than Benz's own 5.0-litre V8, as fitted the ML 500, and backs that up with healthy 165kW. The fuel consumption is also pretty healthy for your wallet with an ADR 81/01 figure (combined cycle) of just 9.4 litres/100km.

This high-tech engine drives through Benz's equally clever (and new) seven-speed automatic gearbox, and from there to all four vehicles via a 50/50 split full-time 4WD system.

COMPETITORS
The 320 CDI's most obvious competition is the BMW X5 3.0d, a $81,700 proposition with a six-speed manual or $84,300 with a six-speed auto. The X5's 150kW straight-six diesel is a smidge less refined than the new Benz oil burner but is still a fabulous drive and a worthy competitor for Stuttgart's latest. Or you can save a few bucks and still get an excellent vehicle in the 128kW 2.5-litre turbo-diesel VW Touareg ($69,900), or get more off-road cred and similar diesel tech to the ML with the new 140kW 2.7-litre Range Rover Sport TDV6 at $85,000.

ON THE ROAD
Want a big surprise? Then get behind the wheel of this new-tech diesel engine. It's so refined and quiet you'll be hard pressed to believe that it's a diesel. You'd also be hard pressed to believe how hard it goes when you squash the go-pedal to the firewall. Despite having to move more than 2000kg of 4WD, it will reach 100km/h in just 8.6 seconds and run to a factory-claimed top speed of 215km/h.

More important than this performance data is the fact that the engine produces its best from low engine speeds so there's always plenty of easily accessible power. Just nudge the accelerator at any speed and the CDI is away...

The engine also mates superbly to the seven-speed auto that offers seamless part-throttle changes and lightning-fast full-throttle changes. It's also intuitive, adapting quickly to your driving style and the road conditions.

Not so pleasing is the dicky steering-column shifter than looks like an indicator wand and has all the substance of the same. Manual-style changes can be made via rocker switches behind the steering wheel but these are awkwardly placed and not easy to use.

Despite its 2000kg- plus weight, the new ML handles surprisingly well even if its steering isn't as sharp or as responsive as BMW's X5. But the new M-Class has a more comfortable ride than its firmly-suspended rival from Munich, important given that these vehicles are designed to be just as happy on a rough gravel road as they are on a freeway. Note that the 17-inch wheels that come standard with the CDI offer a wider choice of robust touring and off-road rubber than the optional 18s and 19s.

With diesel sales of the M-Class running at near 40 per cent for the outgoing model, the ML 320 CDI should be a popular choice in the new model line-up. Given its unbeatable combination of performance and fuel economy it should also be the thinking man's choice, or the thinking woman's choice for that matter.