Diesel engines have a well deserved reputation of being noisy and smelly. We normally think of them clattering under the enormous hoods of industrial haulers. Or we may have friends who use diesel pickups for heavy-duty hauling. Remember the Diesel Rabbit? Slow. Recall Oldsmobile's failed experiment with Diesels in the 1980's? Sigh.
Well, that may be the American story on Diesels, but in Europe they are tremendously popular. Why? They simply are more fuel efficient. However, their byproducts particularly nitrogen oxide have kept them out of American consumers' hands.
Well, that's changing, for two good reasons. One the new ultra low-sulfur diesel fuel makes the characteristic scent a memory. And two vehicles with Mercedes' BlueTEC engine are cleverly handling the emissions issues. This new engine is approved for sale in all 50 states.
The BlueTEC engine uses an oxidation catalyst, a maintenance-free particulate filter and other techniques to clean emissions. The AdBlue system injects a urea solution into the exhaust flow, which breaks the nitrogen oxide down into a harmless form. You need to refill the AdBlue tank at your 10,000-mile oil changes, but there are no other maintenance concerns.
Rudolf Diesel's sparkless compression system has been around for a hundred years and Mercedes-Benz has offered it for a long time, in one form or another. But this new BlueTEC series, available in the Alabama-built ML series SUV, the larger GL-series SUV, the R-series "crossover" and the E-series sedan, has much to recommend it.
Compared to its ML350 gas-powered sibling, the ML320 BlueTEC gets 20 percent better fuel economy, and on the highway, has a cruising range of up to 600 miles. That's San Francisco to Los Angeles with fuel to spare! Official numbers are 18 City, 24 Highway, more typical of a Honda Accord than a two-and-a-half-ton SUV. I recorded 22.6 mpg in mixed driving.
The EPA Green Vehicle Guide gives all MLs a 7 on Air Pollution laudable. The Diesel picks up a 4 for Greenhouse Gas a little below average but one point better than the gasoline powered ML350.
The ML320 BlueTEC features a 3.0-liter Diesel V6 with 210 horsepower, but it pushes out a massive 398 lb.-ft. of torque. So, even though the BlueTEC has 58 less horsepower than the gas ML350, it actually has more torque than the 382-horsepower V8 in the mighty ML550!
Driving the ML320 BlueTEC is completely normal. It starts up immediately there is no waiting for glow plugs. Amazingly, there's virtually no extra noise emanating from the front of the car, either.
The ML uses an efficient seven-speed automatic, which adapts to your driving style. The Diesel goes from 0 to 60 mph in eight seconds only 0.1 second off the performance of the larger engine gas vehicle and quite acceptable. Standard 4Matic four-wheel drive steps in when you need it.
The original ML series out of Alabama didn't feel much like the German-built sedans, but this latest iteration is one of the family. From the grain of the plastics to the body-hugging shape of the firm seats to the genuine wood trim on the console and door tops, it's just right.
I especially appreciated the heated steering wheel during a cold spell in Northern California. I also enjoyed the iPod interface. I controlled everything from the colorful 6.5-inch dash display screen one of the best I've seen. It's part of the COMAND system, which has been updated and simplified, to the relief of Mercedes-Benz drivers everywhere.
Despite its family and cargo hauling role, the ML320 BlueTEC is enjoyable to drive and doesn't feel near as heavy as it really is. A toggle switch lets you choose three suspension settings, Sport, Comfort, and the unmarked middle position. That middle selection is fine for normal driving, but the Sport setting tightens up the feel when the road gets interesting. The Comfort setting is softer, and allows more body motion, not necessarily what you want in a tall, heavy car.
The ML320 BlueTEC is safe, of course, with the usual airbags and crush zones. But there's something new. PRE-SAFE senses an impending collision before it happens, and automatically tightens up the front seatbelts, moves the front passenger seat to a more protected position, closes the side windows, and if it senses an impending rollover, shuts the sunroof as well.
As you might expect, Mercedes-Benz vehicles are premium priced. The ML320 BlueTEC starts at $48,600. That figure is $1,500 above the price of the ML350 gas version, but well below the $55,800 of the ML550.
Bottom line? Diesel ownership is painless today, even though it costs a little more than the usual petrol. Someday soon, maybe small European Diesels will make it stateside and we'll see some really impressive fuel economy. Until then, for SUV room and function with midsize sedan mileage, sample a Mercedes-Benz ML320 BlueTEC.