Mercedes ML350 CDI

Mercedes has built on the old M-Class’s core strengths – and this new version is even more grown-up, offering buyers a more comfortable and more luxurious experience than ever. New features like ‘Active Curve Control’ are welcome but it’s the revised V6 diesel and enormous gains in efficiency that will really be beneficial to UK buyers. All Mercedes has to do now is confirm the smaller four-cylinder diesel and sales will soar. While the looks might be an acquired taste from some angles and the price tag even for an entry-level model is likely to be at least £45,000, it all adds up to a finely honed luxury SUV.  

Over a million Mercedes M-Class models have been sold since its arrival in 1997 – now a third generation of the Stuttgart firm’s luxury SUV is here and it’s faster yet more efficient than ever.  

The new car won’t go on sale in the UK until April next year, but Auto Express headed to Montana in the US to see what buyers can expect from the BMW X5 rival.  

Described by M-Class chief engineer Dr Uwe Ernstberger as offering customers “first class driving pleasure with a clear ecological conscience”, the focus is on cutting emissions and saving fuel like never before.

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As a result, it gets a more slippery shape, which boasts a class-leading drag coefficient of just 0.32. The vast majority of UK sales will be the ML350 CDI Bluetec tested here – a heavily revised 3.5-litre V6 diesel complete with a Blue Efficiency system that includes standard start-stop. 

Hooked up to a new version of Mercedes’ 7G-Tronic Plus seven-speed auto, it make huge improvements, returning 41.5mpg combined (up from 32.5mpg) and emitting just 179g/km of CO2 (down from 230g/km). 

Of course the M-Class will also be available in ML63 AMG spec, with a 5.5-litre, twin-turbocharged V8, but Mercedes UK is mulling whether to bring in a 204bhp 2.1-litre four-cylinder twin-turbodiesel ML250 CDI version too. Returning around 50mpg it will almost certainly be the pick of the new range – if they decide to sell it. What is for sure is that a hybrid version based on this engine will launch in late 2012.  

First impressions are that the M-Class looks less like an aggressive SUV and slightly more car-like than before with styling cues such as the sculpted door panels from the CLS four-door coupe integrated into the new body and the new Mercedes family 'face'. 

Inside, there’s no doubt quality has made a leap forward – the facia is made up of a big sweep of leather, while there’s a chunky slab of wood grain below it, which adds to the feeling of solidity. 

Mercedes’ Command rotary controller is a new feature for the M-Class, while another useful update which will trickle through to the rest of the Mercedes range is a revised multi-function indicator stalk, which has now moved up on the steering column, so that it’s easier to operate (the old one was set too low down). 

While there’s no increase in wheelbase, the new M-Class is longer and wider so there’s a bit more space inside too – you’ll easily be able to transport two tall adults in the back, for instance – while the boot is vast.  

On the move, you’ll barely hear the big V6, which only makes itself known under hard acceleration and just fades into the background when cruising. With 255bhp and 619Nm of torque, up 27bhp and 80Nm on the old engine, it’s rapid machine too – 0-62mph takes just 7.4 seconds (0.2 seconds quicker) but it’s the in-gear response and deep reserves of overtaking urge that impress more. 

Along with the hushed engine comes an almost complete absence of road and wind noise too – this is an extremely refined car that cocoons occupants and travels big distance in comfort with ease. Around corners, the new M-Class isn’t as agile or as involving as a BMW X5, but that’s not what Mercedes buyers want. 

They want a relaxing yet well-mannered experience and with precise steering and excellent body control, that’s what the M-Class delivers. Even standard steel-sprung cars are impressive, but you can specify Airmatic adaptive suspension and a new optional system called ‘Active Curve Control’, which uses active anti-roll bars. These resist roll in bends, but keep the car compliant on the straights.

The ride, on all the models that we tried, was well controlled and comfortable – even on rougher surfaces. Should you wish to go properly off-road, the M-Class is available with a hill descent system, lockable differentials and several different traction settings thanks to an option pack. 

As a luxurious and relaxing way to travel that also boasts big benefits in efficiency, the new M-Class looks set to be a great success.