Mercedes-Benz ML 250 Bluetec

What is it?

Arguably the most interesting real-world prospect brought by the new third generation Mercedes M-class: a four-cylinder diesel version.

Alongside the rest of the ML range, the ML 250 Bluetec will be available to UK customers as of April 2012, when it’ll be the only large premium-brand SUV of its kind that emits less than 160g/km of CO2. Using Mercedes’ twin-stage turbodiesel 2.2-litre engine, it offers 201bhp and 369lb ft of torque, channeled through a seven-speed automatic gearbox.

So can that engine be enough for sufficiently authoritative performance, or sufficiently silken refinement, in as plush a luxury vehicle as an ML? And can any two-something-tonne 4x4 really be made to hit a real world 47mpg?

What’s it like?

Predictably, it’s got a finite quantity of thrust on offer away from a standstill and during overtaking, but matched with Merc’s seven-speed torque converter ‘box, the ML 250’s four-cylinder powerplant does a very respectable job of hauling the ML’s bulk. It won’t excite you, but provides performance on a par with plenty of larger and heavier 4x4s we could mention.

Although you can tell it’s a four-pot, the ML 250 Bluetec’s refinement is excellent too. Quieter and better-mannered than we’ve experienced in various Mercedes saloons, the engine’s noise and vibrations are very well suppressed. This isn’t an engine you’ll enjoy listening to, but thankfully it’s not particularly vocal either.

Underneath the new ML is a platform with double wishbone suspension up front and a multi-link rear end. Steels springs are standard, coupled with adaptable dampers that can be configured for a comfortable ride or more responsive handling. However, our test car had optional Airmatic air suspension, which also comes with two selectable damping modes.

And at first, we had to double-check we were indeed in an air sprung car. Even in ‘Comfort’ mode, the ML has taut handling and suffers little body roll. Its secondary ride isn’t quite as pillowy as you’ll find in a luxury saloon, or even some rival SUVs, so smaller bumps in the road aren’t smoothed out as effectively as they might be. But overall, the compromise is well-met.

Electromechanical power steering is one of the new ML’s routes to greater efficiency. It’s not the perfect system: go for a larger optional wheel and tyre and it seems a little short on power, making the steering heavy and overly keen to self centre at times. And it doesn’t provide the most natural road feel or the same easy sense of precision that you get through the helm of, say, a Land Rover Discovery. Does the car get anywhere near Mercedes’ economy claim of 47mpg? On a reasonably short and varied test route in the Austrian Alps, we saw just north of 38 to the gallon – but even that’s worth commendation when most two-ton 4x4s with permanent four-wheel drive struggle to better 34mpg.

Should I buy one?

This most modest version of Mercedes’ new luxo-4x4 certainly won’t tempt keener drivers out of their X5s and Cayennes. Other, higher-end versions of the ML handle with much more accuracy and swagger, perform better, and get closer to the dynamic standards of the most engaging cars in the class.

But among those who would look for quality, refinement and efficiency, as well as the added practicality and luxury that a premium offroader brings, the ML 250 Bluetec deserves plenty of success. It’s as classy, versatile, comfortable and capable as any of its rangemates – which is more than can be said for every entry-level model.