2007 Mercedes-Benz E-Class Review

Imagine a heavy luxury sedan with strong V-8 performance and four-cylinder fuel economy that gives it a range of more than 700 miles on a single tank of fuel.

A hybrid sedan? No, it's the new 3,860-pound E320 Bluetec turbocharged V-6 diesel model from the popular E-Class line of Mercedes-Benz.

Mercedes sold the world's first production diesel car in 1936 and has been perfecting it ever since. The E320 Bluetec has a low-emissions diesel engine, so its name suggests clear blue skies and high technology.

Rudolf Diesel used peanut oil as a fuel for his engine in 1912, but few cared because gasoline was the fuel of choice for the widely used regular auto engines of that era.

A media preview of the E320 Bluetec was recently held outside this glittering resort city and involved several hundred miles of driving over a variety of roads. The E320 Bluetec showed most won't be able to tell that the E320 Bluetec is a diesel except for a muted version of the characteristic diesel engine sound heard standing near the hood when the engine is idling; the sound disappeared when the E320 Bluetec got under way -- even during 90 mph cruising on rural Nevada roads. Only a "Bluetec" badge on the trunk lid identifies the new model.

The smell, smoke, clattery noise and slow starting and acceleration of 1980s domestic auto diesels are gone. Most of the old diesels were from General Motors. They were troublesome converted gas engines -- not true diesels -- designed to battle a fuel crunch, and they soured many Americans on diesels.

The E320 Bluetec is quite another story. Its diesel has strong acceleration (0-60 mph in 6.6 seconds) and delivers an estimated 37 mpg on the highway and 26 in the city. EPA-estimated diesel economy figures generally are closer to real-world figures than estimated figures for regular gasoline-engine cars and gas/electric hybrid autos.

A smooth, responsive seven-speed automatic transmission enhances performance and fuel economy of the E320 Bluetec.

This new Mercedes has a 21.1-gallon tank, so its driver won't be stopping much for fuel. On long trips, Mercedes estimates you'll go nearly twice as far between refueling stops as a typical gas-powered car, depending on the size of your auto's fuel tank.

Around town, you're likely to fill up your diesel Mercedes just three times a month, while your neighbor with a gas car will probably fill up at least twice weekly. Standard fuel economy ratings for the E320 Bluetec top those for a hybrid of comparable size and power.

Where can you get diesel fuel? At least 42 percent of all fuel stations offer such fuel for diesel-engine SUVs, pickup trucks and such cars as Volkswagens -- and older Mercedes diesel models. Some 80 percent of fuel stations initially must offer the new Ultra Low Sulfur Diesel (ULSD) fuel required by the E320 Bluetec, starting Oct. 15.

That means up to 76,500 filling stations in America and most in Canada could carry the new fuel in the first phase of its introduction. Mercedes says it will inform an E320 Bluetec owner of the nearest diesel-fuel station if he or she can't find it.

About 75 percent of Mercedes cars sold here in the 1980s were diesel powered, mostly because of an increase in gasoline prices. But few really cared what powered a Mercedes because its only direct rival was Cadillac. Also, Mercedes diesels had a reputation for lasting practically forever.

The E320 Bluetec's 3-liter diesel V-6 has 208 horsepower. But it produces 400 pound-feet of torque, which tops the torque rating of most V-8 models. Torque is a diesel strong point, and it's torque a driver feels when he accelerates quickly. (Horsepower mainly determines top speed.) The 400-horsepower Chevrolet Corvette 6-liter V-8 also generates 400 pound-feet of torque.

DaimlerChrysler is composed of its Mercedes and Chrysler (Chrysler, Dodge and Jeep) units, and officials at the preview here said the Bluetec diesel eventually will be used in Chrysler unit vehicles, such as the Jeep Grand Cherokee.

Many gas/electric hybrids cost considerably more than regular gas engine models, but the $51,550 E320 Bluetec only costs $1,000 more than the standard gas engine E-Class, which has been Mercedes' top or second-best-selling car here for years and has been revised for 2007 (July 24 AutoTimes).

Half the cars in Europe have diesel engines largely because of stiff gasoline prices and major improvements made to the performance and refinement of diesel engines. But the hangup in America has been low gasoline prices and the lack of cleaner low-sulfur diesel fuel. Without such fuel, the E320 Bluetec can't meet low emissions levels.

Fortunately for Mercedes, the cleaner new diesel fuel, which contains less than 15 ppm sulfur content, will be available across America and Canada. The old sulfur content in diesel fuel was 500 ppm, so sulfur is reduced by 97 percent.

The Bluetec diesel uses several coordinated technical measures to minimize emissions within the engine and provide for effective exhaust gas treatment. Used are such items as an oxidation catalytic converter and a particulate filter, besides new techniques for reducing nitrogen oxide emissions.

The E320 Bluetec initially will be sold in 45 states. Mercedes is negotiating with clean air officials to sell the car in California and several Northeastern states, which have stricter emissions regulations than other states.

Those states are tough nuts to crack, but Mercedes has an ace up its sleeve: AdBlue injection. AdBlue is an aqueous carbamide solution injected into the engine exhaust flow. Ammonia consequently is released to reduce nitrogen oxides to harmless nitrogen and water in a catalytic converter. The AdBlue tank needs to be refilled only during regular maintenance checks.

The E320 Bluetec doesn't mean Mercedes is giving up on hybrid vehicles. Officials of the automaker said at the preview here that a diesel/electric hybrid will be more effective than today's gasoline/electric hybrid.

"The diesel will make a contribution to consumption and emission reductions over the next few years that will be many times larger than that achieved by gasoline hybrids,'' the officials said. 

2007 MERCEDES-BENZ E320 BLUETEC 

PRICE: $51,550

LIKES: Four-cylinder fuel economy with V-8 performance. Old diesel drawbacks gone.

DISLIKES: Every service station doesn't have diesel fuel. Still prohibited in California and some Northeastern states.