2007 Mercedes-Benz ML320CDIPosted on July 10th, 2007
Diesel for a small planet
By Nina Russin
I’m listening for the sound of diesel tick, but there is none. No clapity-clapity-clapity under the hood, and no black smoke billowing from the tailpipe. When I push on the gas pedal, I don’t have to count “One banana, two banana,” before the car moves forward. Acceleration off the line is strong and linear. This can’t possibly be a diesel, or can it?
Here’s the best news: after over a hundred miles of city and highway driving, the gas tank is still three-quarters full. In fact, the new Mercedes-Benz M-Class CDI gets better fuel economy than its gas-powered cousins: about twenty-five percent better to be exact.
Why are the new diesel cars so much better than the smoke, belching, sluggomobiles of yore? One reason is that the fuel itself is better. By federal ordinance, gas stations have to make reduced-sulfur diesel available this year. The reduced sulfur content enables engineers to use more effective emissions controls on the cars.
The second, and perhaps most important advance has to do with the on-board computers that manage engine function. The new common-rail diesel engines inject fuel directly into the cylinders, giving the engines better power delivery and fuel economy. The turbochargers on the new M-Class CDI boost airflow through the engine by using exhaust-driven blowers. Since internal combustion engines are inherently inefficient, there’s almost no such thing as too much air, especially when the on-board computer can make instantaneous adjustments to the air/fuel mix, depending on the driving conditions.
Miles to go before I refuel
I start my M-Class test drive in rush-hour traffic. At five in the afternoon, the 101 freeway in Phoenix’s east valley is a parking lot. Maximum speed rarely tops 25 miles-per-hour. I pop in a compact disc and prepare for the long haul.
An hour later, I arrive at my destination, which is coincidentally about twenty-five miles from where I started. The gas gauge is still on “full.” The drive home is about ten miles longer. The needle has moved slightly, but not much.
The following day, I have to haul a few cartons of shoes between our two running shops. This will be a good chance to test the fold-down mechanisms on the second-row seats. The seat cushions flip forward; the seatbacks fold flat using a lever on the outside edge of each seatback. The operation takes about thirty seconds for each side. Once completed, there’s a large, flat load floor with cargo tie-down loops. I’d prefer an easy-to-clean vinyl floor to carpeting, but the carpeting wouldn’t stop me from buying the car.
The M-Class could easily hold a bicycle with the front wheel removed with the second-row seats in place. With the seats folded flat, it could easily hold several, or in this case, about fifty pairs of shoes, a large clothing rack and the clothes that were hanging on it.
This time traffic is lighter, so I can test the car’s acceleration, steering response and braking. The M-Class has plenty of punch off the line, merging into high-speed traffic, and passing other cars on the highway. A fully-independent suspension smoothes out any bumps in the road. The car rides on seventeen-inch wheels and R-rated tires, which give it a nice, stable footprint. The rack-and-pinion steering system offers excellent driver response, and a respectable turning radius of 37.9 feet.
All cars come with a seven-speed automatic transmission, that the driver operates using a small, finger-sized lever on the steering column. The lever eliminates the long shift lever on the center console, giving the driver more elbow room.
The M-Class has unibody construction, giving it the ride and handling of a passenger car. While unibody construction isn’t quite as durable as body-on-frame, it will probably meet the needs of most drivers, who drive on dirt roads, but who aren’t planning to tackle the Rubicon trail. Having driven the gas-powered M-Class through deep mud, over exposed roots and boulders, I can speak for its off-road capability, which is considerable. Permanent four-wheel drive is standard, but the M-Class doesn’t have a two-speed transfer case to provide the extremely low gears that some off-road driving requires.
Standard downhill speed regulation and hill-start assist make it easy to climb and descend steep hills in complete control. The hill-descent function maintains a speed of between three and ten miles-per-hour, according to the driver’s choice, without using the brakes. The hill-start feature maintains brake pressure for a second after the driver releases the pedal, to keep the vehicle from sliding backwards on a steep hill.
The round trip between the two shops adds another forty miles or so to the trip meter. The needle is about half way between the “full” and “three-quarters” marks. I’m relieved to know that the gas gauge works: I was starting to think that it might be stuck.
Inside, pure luxury
After all, it’s a Mercedes. The optional leather trim may not be practical, but it sure is comfy. Eight-way adjustable front bucket seats are standard, as is a power tilt-and-telescoping steering wheel.
The Germans have finally accepted the fact that Americans won’t buy cars without cupholders. The M-Class has two, generous-sized cupholders in the center console: each will hold a large water bottle firmly in place. There are two additional cupholders for the rear-seat passengers. The two-tier bin in the center console has plenty of room for electronic devices or a small pack. The glovebox, also generous sized, has a jack for MP3 players or iPods. There are four twelve-volt power outlets.
Both rows of seating have plenty of leg and shoulder room for adults. The test car came with the optional heating package that includes a heated steering wheel, front and rear heated seats. The warm spring weather in Phoenix wasn’t conducive to testing the seat heaters, but they’re a nice feature for drivers who live in four-season climates.
High level of standard safety
Safety has always been a Mercedes-Benz trademark: the M-Class is no exception. Standard safety features include four-channel, antilock brakes, traction control and electronic stability program, front, side and side-curtain airbags, front knee bolsters and front active headrest restraints.
Visibility is good all the way around the vehicle. There is a standard rear wiper for rainy or snowy days. Mercedes-Benz’s Tele Aid system uses GPS to offer real-time vehicle location. Drivers can receive emergency assistance, information, or mechanical help by depressing the appropriate buttons on the rear-view mirror. Any driver who’s had a flat tire or run out of gas in the middle of the night knows how handy such a feature can be.
Large, functional cargo area
The cargo area comes with a standard tonneau cover to keep items out of sight. The cover is easy to remove for large loads by depressing a spring to one side. A button on the key fob automatically raises and lowers the rear hatch, making it easier to load large items in back. Roof rails are standard. Towing capacity is 5,000 pounds.
The M-Class is assembled at Mercedes-Benz’s Vance, Alabama plant. The ML320CDI is currently available for test drives at dealerships nationwide.
Likes: Exceptional fuel economy with no sacrifice in power and performance. The new common-rail diesel is also environmentally friendly. The M-Class is a great choice for drivers who want a mid-sized sport-utility vehicle with the ride and handling of a passenger car, and some off-road capability.
Dislikes: Availability of low-sulfur diesel fuel is still somewhat limited.
Base price: $43,680*
Price as tested: $59,425
Horsepower: 215Hp @ 3800 r.p.m.
Torque: 398 lbs.-ft. @ 2800 r.p.m.
0 to 60: N/A
Antilock brakes: Standard
Side curtain airbags: Standard
First aid kit: No
Bicycle friendly: Yes
Fuel economy: 21/27 m.p.g. city/highway
Comments: * Base price does not include $775 destination and delivery charge.
One response to “2007 Mercedes-Benz ML320CDI”
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