Sure, diesels are 30 to 40 per cent more fuel efficient than gas engines of comparable performance. That's the good news.
Also good: diesels are ideal for the driver who hauls or tows (lots of torque or twisting force at the wheels where it counts). And for the driver wants range, who wants to minimize fill-ups, a tank of diesel typically will do for 1,000-1,200 km.
Unfortunately, most of the diesels passenger vehicles in Canada are pretty pricey. The Mercedes-Benz ML350 BlueTec, for instance, starts at $58,900.
Will we ever share Europeans' taste for premium-priced small cars?
Add leather upholstery, and you're up $2,500. The $4,500 Premium Package (navigation system, voice controls, parking assist, heated rear seats, power lift-gate, three-position memory settings, power tilt/telescoping steering column) puts you into the mid-$60,000s. Keyless entry and push-button start? Tack on another $975. An iPod/MP3 interface is worth another $375, while freight is $1,995. Now you're getting near $70,000 before taxes.
So the ML diesel is not inexpensive. Nonetheless, diesels have become the German brand's single most popular powertrain offering thanks to an emissions scrubbing system called BlueTec. For the record, "Blue" is the new green in marketing-speak.
And diesels are a big piece of Mercedes-Benz's long-term strategy to meet tough carbon dioxide emissions rules in Europe, as well as demanding fuel economy regulations in Canada and the United States.
The Alabama-built ML SUV arrived with the latest "clean" diesel technology as a 2009 model. I say clean because this diesel's emissions are scrubbed enough to allow sales in all 50 U.S. states, including Vermont and California where you'll find the toughest tailpipe emissions standards on the continent. In government regulations-speak, they are certified as Bin 5 ULEV (ultra low emission vehicles).
Emission standards are tough on smog-forming NOx (oxides of nitrogen) and particulates (those little sooty black bits that, unfiltered, come out of diesel tailpipes). So to get legal, Mercedes is one of several auto makers to perfect an exhaust after-treatment system.
In the ML350, the diesel powertrain is rated at 210 horsepower, but the more impressive number is 400 lb-ft of torque at a very low 1,600 rpm. That's a mountain of torque. Moreover, the standard seven-speed automatic has plenty of gears to make the most of the available power.
Stab the throttle and 100 km/h arrives in nine seconds or so, with city fuel economy rated at 11.1 litres/100 km, while on the highway it's 8.0 litres/100 km. Not bad for a truck that weighs 2,255 kg and has a maximum tow rating of 3,266 kg.
The Mercedes diesel here is reasonably quiet and rattle-free; it is nothing like any of the diesels you'll find in an 18-wheeler and light years ahead of the horrible, nasty, detestable diesels pawned off on unsuspecting consumers by Detroit-based auto makers in the late 1970s and early 1980s. Many drivers will be hard-pressed to even notice they're wheeling about in a diesel. The engine is that quiet and smooth.
The rest of the ML is quite nice, but nothing particularly special. The exterior design is pleasant and understated; the big design feature is a grille sporting silver louvers with chrome highlights.
Inside, a four-spoke multifunction leather steering wheel with paddle shifters is useful enough. For gadget lovers, a telematics system is capable of integrating Bluetooth cellphones. It also allows passengers to run an MP3 player via the ML's own audio controls.
The point is, the advantage Mercedes has in the crossover SUV market is not the design of the ML or its features. The diesel engine is the edge Mercedes has when compared to rivals such as the Honda Pilot, Ford Edge and Flex, Toyota Venza, Mazda CX-9, Hyundai Veracruz and others. Take away the diesel, and the ML does not stand out in this pack.
But the ML does have the BlueTec diesel and it's quite an asset. Could other elements be better? Sure. The seats are not just firm, but hard and after a couple of hours they left me tired and a bit achy. Also, the ride is bumpy and jiggly on even smooth pavement despite the ML having three suspension settings: comfort, normal and sport.
So here's where we are with the ML350: Mercedes has room to improve this rig, but the diesel powertrain is not where effort is required for now.
2010 Mercedes-Benz ML350 BlueTec
Type: Mid-size SUV
Price: $58,900 (plus $1,995 freight)
Engine: 3.0-litre V-6
Horsepower/torque: 210 hp/400 lb-ft
Transmission: Seven-speed manual
Fuel economy (litres/100 km): 11.1 city/8.1 highway; diesel fuel
Alternatives: Honda Pilot, Ford Edge and Flex, Toyota Venza, Mazda CX-9, Hyundai Veracruz, BMW X3