Mercedes-Benz ML 320 BlueTec Review

Noise? No.

Smell? No.

Slow acceleration? No.

Trouble passing emissions? No.

Must not be a diesel, right? Think again. Mercedes-Benz new BlueTec has done what a lot of people said was impossible just a few short years ago...passed tough new emissions testing in all 50 states without substantial and expensive reformulation of diesel fuel.

How clean is it? Well, I stood by the tailpipe of our idling ML320 test car last week and couldn't detect a trace of diesel smell.

Those tough regulations have kept many diesels off the U.S. market for the past few years. A shame, too, since diesels have huge benefits including great fuel economy and long engine life.

If you've avoided diesels like the plague since the dark days of the 1980s, when smell, slug-like 0-60 times and (in the case of GM diesels) questionable reliability were the norm, the ML320 BlueTec would be a perfect introduction to the state of the art. First, there's no waiting for the glow plugs to heat up to start (that one's been gone for a decade or more), neither the inside nor the outside of the ML320 BlueTec smells like a city bus pulling away from a stop, it doesn't clatter like diesels used to and it performs much like a gasoline-powered engine...but with multiples of torque and miles per gallon.

A gasoline-powered ML320 is probably a 16-mile per gallon vehicle in the city. The BlueTec version we tested did 23 and a half. The trip computer showed 550 miles range when we started...and it actually crept close to 600 on the freeway. Yes, diesel fuel costs more than gasoline these days, but the difference in economy tips the scale in the BlueTec's favor.

And then there's longevity. Mercedes' gasoline engines are well-engineered...200,000 miles with proper maintenance should be no sweat. A Mercedes diesel? 400,000 or 500,000 is more like it. And there are million-mile examples out there.

If you're shopping for a luxury mid-size SUV but want clean air, better mileage and a long-term payoff on your investment, the ML320 BlueTec makes a very strong case for itself.