2009 Volkswagen Jetta TDI
The 2009 Volkswagen Jetta TDI is one of two Volkswagens available with a diesel engine. VW also offers the Touareg TDI.

2009 was supposed to be the year of the diesel. A slew of new models was going to make the option of a diesel-powered vehicle more available to American car shoppers for '09 than at any time in the past 20 years. That's still sort of the case, but rising diesel-fuel costs, and a couple of discontinued models have softened the potential excitement somewhat.

There's still a good number of models to choose from, but the options lean towards the pricey side of the market, and the number of diesel-powered trucks outnumbers cars almost two to one.  

What's Out There

Mercedes-Benz is the volume leader, offering a diesel-powered version of every one of its midsize and large SUVs, as well as its E-Class midsize sedan. All four Mercedes diesel models are available in California and the other "green" states, though in California the E-Class is only available for lease.  

Volkswagen shuffled its diesel offerings for 2009. Returning after a one-year hiatus is a diesel-powered version of the compact Jetta sedan. Not returning after disappearing for 2008 is a diesel-powered version of the New Beetle. Back as a diesel, but with a new engine is VW's Touareg SUV. For '09 the Touareg trades its enormous 5.0-liter V10 diesel engine for a more sensible 3.0-liter V6.  

Audi enters the fray with a diesel version of its Q7 SUV. As the Q7 shares its basic architecture with the VW Touareg, it stands to reason that it shares the big VW's 3.0-liter diesel V6. Look for Audi to roll out a diesel version of its compact A3 sometime later this year.

BMW avoids being the only German carmaker not in the game by introducing a diesel-powered version of its popular 3-Series model. The diesel 3-Series can only be had as a sedan, though gas-powered coupes, convertibles, and wagons are also offered. Also new this year is a diesel-powered version of the midsize X5 SUV. Look for a diesel version of BMW's midsize 5-Series car to arrive on our shores within the next year.

Gone for 2009, after just one year of availability, is the diesel Jeep Grand Cherokee. A victim of parent-company Chrysler severing ties with Mercedes parent Daimler. While Chrysler looks around for a diesel engine to replace the Mercedes V6 it was using, the Grand Cherokee soldiers on with conventional gasoline-powered V6 and V8 engines.

Why Choose a Diesel?

The obvious reason has long been economy. Though diesels generally cost more at the time of purchase, reduced fuel consumption, generally by 25-35 percent, usually offsets that cost over the duration of ownership. For many years, diesel fuel cost less than gasoline, expediting the payback.

The downsides to diesel ownership have traditionally been crude engine behavior, diesel smoke, and difficulty finding fuel in some locations.

But things have changed. Modern diesel engines, especially those now being retailed in the U.S., are amazingly refined, with excellent performance and little visible exhaust.

Sadly, a soft economy has wreaked havoc on the petroleum market, and diesel fuel now costs more than gasoline in most domestic markets. And current trends don't make diesel any more attractive financially. When gasoline averaged $3.00 per gallon, diesel ran about $3.30, a ten percent bump. But when gas slipped to about $2.00 per gallon, the average price of diesel only fell to $2.60--completely offsetting any fuel economy benefits.

So, why buy a diesel? There are a couple of good reasons. One reason is power. If you plan to tow, nothing beats a diesel engine's ability to generate low-end torque. Another is range. In Consumer Guide testing, a Mercedes-Benz GL320 averaged 22.2 mpg in mixed city/highway driving. Multiply that by GL's 26.4-gallon fuel tank and you have almost 600 miles of real-world range between fill ups. Finally, it's unlikely that the disparity between gas and diesel prices will last in the long term.  

Diesel fuel production is tied directly to gasoline production. Because of an economy-related reduction in gasoline refining, less diesel fuel is being produced. Diesel demand, however, is more commercial and thus less discretionary and hasn't fallen as steeply. What this means is, once the economy rebounds and gas demand rises, diesel prices should fall relative to gasoline.
   
Note also that according to Kelly Blue Book, the resale value of most diesel-powered vehicles is higher than their gasoline-fueled counterparts. Also note that the following overview does not include the heavy-duty diesels available in full-size pickups from Chevrolet, Dodge, Ford, and GMC.