2012 Mercedes ML350 BlueTEC Diesel Review

Colum Wood
by Colum Wood

There are a few commonalities you can find among almost all auto journalists. For the most part all love sporty back to basics cars, they like hatchbacks and wagons, understand the amazing functionality of a minivan and have an appreciation for old and quirky cars. And almost universally they love diesels.


1. All new for 2012 the latest generation Mercedes M-Class is available with four engines, a 302 hp V6 powered ML350, a 402 hp twin-turbo V8 powered ML550, a 518 hp twin-turbo V8 ML63 and out diesel tester.
2. The ML350 BlueTEC diesel makes 240 hp and 455 lb-ft of torque at just 1600 rpm.
3. Fuel economy is rated at 20 mpg city, 27 mpg highway and 22 mpg combined.
4. Priced at $51,365 it’s just $1,500 more than the base gas V6.

Sure to be an outcast among my peers for saying so, that last part in no way reflects me.

What’s wrong with a torquey diesel engine? Where to start? They’re loud and unrefined, which particularly stands out in the premium European products you tend to find them in. Sure they’re much quieter than they used to be, but so are gasoline engines. Torque? Sure, they have lots of torque at 2000 rpm, but the power drop off is as abrupt as hitting a curb on your bicycle.


With a few exceptions, like the BMW 335d and even Mazda’s new Skyactiv diesel powerplant, diesels aren’t my thing. So I was surprised at how much I liked the powertrain in the Mercedes ML350 BlueTEC – one of several new M-Class models that have been fully redesigned for 2012.

For starters the BlueTEC model is so quiet that if you weren’t told, you might not guess it was a diesel. That is, until the temperature drops. Californians might never notice, but get down below 50 degrees and the cold temp idle will fill your neighborhood with clackety sound.

Power comes on smooth and as a diesel you won’t need to apply much pressure to get the desired result. The 3.0-liter diesel V6 might not be large and a rating of 240 hp isn’t significant, but the impressive 455 lb-ft of torque at just 1600 rpm certainly is. Revving it out doesn’t do much good, however, as that peak torque rating doesn’t last beyond 2400 rpm. A performance machine it’s not, though it does boast a rather quick 7.3-second 0-60 time. Instead it does feel fully capable, a lumbering truck with a surprising ability to pounce.

Attractive for those who want a high-riding luxury machine with prestige, the ML350 BlueTEC delivers on its utility promise too. Sure it has the same 7,200 lb tow rating as the regular gasoline V6, but all that torque will make the task feel effortless by comparison.


Then of course there’s the advantage of diesel fuel economy. While the gasoline version gets a decent 17/22 (city/highway) rating for a combined 19 mpg, the BlueTEC is rated 3 mpg higher across the board at 20/27/22 mpg. During our week with the luxury ‘Ute we managed 23 mpg average.

If there is a down side to the diesel engine it’s that it requires regular fillups of AdBlue diesel exhaust fluid (DEF), which is required to make the engine meet strict emissions targets. Fill-ups must be done roughly each oil change and can be expensive, especially at the dealer.


The torquey engine suits the driving experience of the ML350 as well. A luxury machine, it can’t hide its truck roots. While the steering is precise and responsive, it does require more than minimal input.The SUV then responds (after the fact), tilting into the desired direction to follow the wheels. Refine the SUV they have done, but the ML is still well off the Acura MDX or Infiniti JX in terms of a car-like driving feel.

Helping to combat this is an Airmatic feature that comes with the pricey $5,150 Dynamic Handling Package, with an air suspension that adjusts to suit the conditions, plus some stylish 20-inch wheels to help add some aesthetic value to the price tag. As well, adjustable shock absorbers work to deliver a more engaging or comfort-oriented drive, depending on the situation. Airmatic, as the name suggests, automatically lowers the car by 30 mm at highway speeds to reduce aerodynamic drag and improve handling. At speeds above that the system will drop the SUV another 15 mm. Yet another feature is Active Curve, which adjusts the air suspension at each corner to help keep it level. Not only is this a performance feature, it also makes for a less turbulent ride for your passengers.

Not present on our test car, without these features the ML does feel as though there’s too much disconnect between the wheels and the chassis.

Looks are deceiving too with the ML, a surprisingly large model. You do actually have to step up into the cabin, which is expansive. Rear seat space is plentiful, as is cargo room. Again, you’ll be surprised to discover 36 cu-ft of cargo room, and that can be as much as 71 cu-ft with the rear seats folded flat.


While undoubtedly a luxury model, the standard MB-Tex seating doesn’t look or feel particularly high grade. Leather isn’t standard and adding it will up the entry price by $1,650. Well equipped in basic trim, the 2012 ML gets 8-way power heated front seats with lumbar, not to mention dual-zone climate control, Bluetooth, rain sensing wipers, a power rear liftgate, plus a 4.5-inch digital trip display between the main gauges as well as a 7-inch COMAND screen on the dash.

It is, however, missing some must-haves for a luxury model of this caliber, like the brand’s Keyless Go system with push-button ignition, which is a $650 option. Plus, if you want navigation and a back-up camera on that display screen you’ll have to opt up to the $3,600 Premium 1 Package, which also includes a driver memory system and power tilt and telescopic steering wheel among other features.

It’s hard not to complain about the dated look of the COMAND system, although one handy new feature has been added to Sirius satellite radio display. Rather than hunting through the notoriously slow-to-load channels, you can now scroll past each station and the song currently playing will display.


Often bought as a family hauler, safety cannot be ignored. Since the introduction of the current E-Class, Mercedes has made safety a priority and the ML is no different, though as expected you’ll have to pony up for the more advanced features.

Standard safety equipment includes nine airbags, as well as items like tire pressure monitors and stability control – which are government mandated and now come on every car. A modest $850 will get you blind spot assist and lane keeping assist, which vibrates the steering wheel to alert you to get back in your lane.

Taking safety to the next level is the $2,950 Driver Assistance Package, with brakes that engage to pull the SUV back into its lane. Included in this kit is Distronic Plus, a fancy term for a fancy setup, that not only delivers full speed cruise control (a luxury feature must-have in congested traffic areas where the car does all the stop-and-go for you) but which will also apply full brakes if the car detects a collision is imminent.


While the gasoline ML is less than competitive with Japanese rivals like the Acura MDX and the new Infiniti JX (which start at almost $10K less), many will still flock to it for reasons of brand prestige. The BlueTEC diesel, however, offers select competitive advantages ranging from fuel economy to towing, not to mention the feel of a diesel powerplant that some may prefer.

Priced at $51,365 the diesel premium is just $1,500 meaning that if your luxury SUV simply must have a Mercedes badge, the diesel isn’t just the best pick, it’s the only one.


  • Diesel fuel economy
  • Small price premium
  • Strong tow rating


  • Base seating looks too low grade
  • Still drives too much like a truck
  • Added cost and hassle of AdBlue
  • Expensive
Colum Wood
Colum Wood

With AutoGuide from its launch, Colum previously acted as Editor-in-Chief of Modified Luxury & Exotics magazine where he became a certifiable car snob driving supercars like the Koenigsegg CCX and racing down the autobahn in anything over 500 hp. He has won numerous automotive journalism awards including the Best Video Journalism Award in 2014 and 2015 from the Automotive Journalists Association of Canada (AJAC). Colum founded Geared Content Studios, VerticalScope's in-house branded content division and works to find ways to integrate brands organically into content.

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 1 comment
  • Bobby Bobby on Aug 27, 2013

    Yes, but the cost of the ML is much much higher than in the States, which ultimately evens out to give Aussies 'better value for money'.