2007 Mercedes Benz E320 Bluetec
 Road Test Review

Looking back at their history in the United States, I can understand why most Americans have never shown a lot of interest in diesel power for their automobiles.

The best of the diesel cars – no doubt Mercedes-Benz products –  have traditionally been sluggish and noisy, with a proclivity for belching a stream of nasty-smelling, noxious black smoke out the exhaust pipe.

Their strength and their appeal to a loyal band of followers were their fuel-sipping habits and their exceptional longevity. The German-made diesel cars routinely provided hundreds of thousands of trouble-free miles.  During the 1980s, Mercedes-Benz diesel cars actually became popular among the well-to-do and accounted for 80 percent of the German manufacturer’s U.S. sales.  Some of those cars are still on the road today.

The worst of them –  arguably the General Motors diesel cars developed quickly after the gas shortages of  30 years ago – were powered by converted V-8 gasoline engines that had all the negative traits of the German powerplants plus a general reputation for unreliability.

When the fuel crisis finally abated, even buyers who had been swayed by the fuel efficiency turned away and diesel-powered cars pretty much faded from the picture. Mercedes-Benz continued selling diesel cars in the United States through the 1999 model year, but never in great numbers.

Dirty, sluggish, smelly, noisy polluters – not exactly a recipe for big-time sales success.

But what if you could have the important fuel-saving advantage of a diesel car and none of the disadvantages? Actually, you can, thanks to Mercedes-Benz. which introduced diesel power to the automobile more than 70 years ago in its 1936 260D sedan.

After an absence of five years, the German manufacturer re-entered the U. S. market in 2004 with an E class diesel sedan powered by a 3.2-liter turbocharged, in-line six-cylinder engine.

Nearly as quiet as a gasoline engine, except at start-up, it produces 201 horsepower and a hefty 369 pound-feet of torque. It can match the acceleration of the gasoline-powered six-cylinder E class sedan and return an EPA-rated 27 miles per gallon of fuel around town and 37 mpg on the highway.

A common-rail injection system that squirts fuel directly into the cylinders under extremely high pressure eliminates mostly of the diesel clatter and reduces the emissions of nitrous oxide and soot into the air.

But, the pollution problems were not completely solved and the E320 CDI, as the car was called, could not be sold in five states, including California and New York.

For the 2007 model year, Mercedes has introduced a new diesel powerplant, which it calls Bluetec. It is a 3-literV-6 engine, again featuring turbocharging and direct rail injection.  Like its predecessor, it is quiet, smooth and lively.

This one produces 209 horsepower and 400 pound-feet of torque, enough to propel the E class sedan from a stop to 60 mph in 6.6 seconds and return EPA-rated fuel mileage of 26 mpg city, 37 mpg highway.

The V-6 diesel’s use in the United States was made possible by new regulations that require the sale of low-sulfur fuel. The 2007 sedan is cleaner than its predecessor but still legal only in those 45 states.

That is about to change.  For the 2008 model year, one more pollution prevention step will be added to the Bluetec.  It involves adding AdBlue, liquid urea, to the exhaust stream to reduce nitrous oxide by 80 percent.   That should make the car legal in all 50 states.  The only hang-up is that the supply of AdBlue must be replenished at regular maintenance intervals.

And what about the rest of  the car?

In every other respect, the Bluetec is essentially identical to all of the 2007 E class sedans.

It has the same heavy, solid feel. The steering is accurate, the brakes are strong, acceleration and passing power are brisk.  It is not sporty, nor is it intended to be, but it is a satisfyingly comfortable cruiser.

Over a weekend, I took the car on a journey of 426 miles. The long stretches of open road were interrupted by several lengthy traffic jams and the rest of the time was spent in small towns with red lights, stop signs and a 25 mph speed limit.

I averaged 32 miles per gallon, with a high of 36 mpg during one easy-driving stretch, and a low of 26 mpg in the small towns.  When I returned home, the trip computer advised me that I still had 256 miles to go to empty.  Credit that in part to the 21 gallon fuel tank.

Inside the Mercedes, a maximum of four adult passengers are treated to first-class accommodations featuring comfortable and supportive leather seats; elegant burl walnut trim; a first-class sound system; automatic, dual-zone climate control; and sound-proofing that isolates them from the annoyances of the outside world.

Other comfort and convenience accessories include a power sunroof, 10-way power front seats, rain-sensing wipers, auto-dimming rear and side-view mirrors and an in-dash, 6-cd player.

Safety is given the highest priority, with front and side airbags for front-seat passengers, side airbags for rear-seat passengers, side-curtain airbags to protect the heads of all four passengers, a rollover sensor, traction control, stability control, the four-wheel, antilock disc brakes, and an advanced feature known as PRE-SAFE.

If PRE-SAFE sensors detect an impending collision, the seatbelts are automatically tightened to hold the occupants more securely in place. If they detect that the front passenger seat is too close to the dashboard, or the seatback is too far reclined, or the seat cushion is positioned wrong, the system will automatically adjust them to safer settings. If the vehicle goes into a skid that signals a possible rollover, PRE-SAFE will automatically close the sunroof and side windows.

And, if an accident is averted, the system will automatically ease the tension on the seatbelts.

When a collision does occur and the seat-belt tensioners and/or air bags deploy, the Mercedes-Benz Tele Aid emergency communication system automatically calls 9-1-1 to tell emergency personnel the vehicle’s location, plus its model and color.

In addition to the new engine, a new, smoother, seven-speed automatic transmission replaces the former diesel’s five-speed shifter. When full acceleration is required, It has the ability to skip several gears to a ratio that offers maximum power.

Base price of the Mercedes-Benz E 320 Bluetec is ,550, a ,000 premium over an E 350, which has a V-6 gasoline-engine that offers comparable performance.

The suggested price jumps to ,375 with the addition of platinum blue paint (0), walnut and leather steering wheel (0), electronic trunk closer (0),  Premium II package (,290), and delivery charge (5).

The Premium II package includes a navigation system, satellite radio, heated front seats, power rear-window sun screen, hands-free communications system, keyless door locks and ignition, Bi-Xenon headlights with curve illumination and headlight washers.

Mercedes-Benz appears to be on a mission to convince American motorists of the many benefits of the new diesel technology.

In addition to the E Class sedans, diesel power is now available in the ML and and GL sport-utility-vehicles and its R class luxury wagons. Because of their high prices, these vehicles will never bring diesel power into the American mainstream regardless of their proven benefits.

But Mercedes has also has worked out an agreement with Jeep, Audi and Volkswagen, which sold diesel cars in the United States through 2006, to bring the Bluetec name and technology to their diesel products. Many of these vehicles will certainly cost a lot less.

All are betting that Americans will change their long-held opinions about automotive diesel power once they get a chance to experience it.

And why shouldn’t they? It’s hard to think of anybody who wouldn’t prefer a significant reduction in fuel consumption and pollution with no sacrifice in comfort, convenience or performance.