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Myths abound about the new generation of clean diesels set to sweep the marketplace this fall (Mercedes E, R, ML, and GL, BMW 3 Series and X5, Audi Q7, Q5, A4, A3, VW Jetta TDI). In an attention-getting headline, our sometimes cynical peers over at Jalopnik blasted this one today: "New Benz BlueTec Diesels Won't Run Without Urea." True? Err...kinda. Attention-getting? Bingo. Hey, it's election time, so we're used to quick soundbites that grab the attention. But just like political prose and negative campaigning, we'd advise a much closer look.

1) Mercedes' new 50-state legal 3.0-liter turbodiesel V-6 engine, which goes under the trade name BlueTEC in its E-Class, R-Class, ML-Class, and GL-Class vehicles, does not need urea to run. Period.

2) The new BlueTECs do need urea to meet U.S. emissions standards, and as such M-B brokered a deal with the EPA to ensure that if the seven-gallon urea tank goes empty (seven gallons are expected to last roughly 10,000 miles), the vehicle's emissions systems will only allow 20 additional starts until your Benzo says, "No mas!" So, supposing you've completely ignored the array of warnings, lights, and readouts telling you to head to your local M-B dealer to get the urea tank refilled, yes, you'll get exactly 20 more starts and not one more.

3) We suppose, if you're ultra-stubborn, you can do what schoolbus drivers in Detroit and Minneapolis do in January, and leave your Benz diesels idling all night long (in the case of the former, so the old low-tech bus diesels won't refuse to crank on the bitterest of mornings). You could, indeed, save those 20 starts for 19 oil changes, and just leave the engine running interminably. Diesels are ultra-efficient at idle, where they also don't produce a big thermal load on the cooling system, so she'd purr happily away while you sleep. And you'd never have to change the urea for, say, 200,000 miles. Ha ha! Take that, Uncle Sam and the EPA!

Or, simply, having decided to purchase one of Mercedes-Benz's new efficient, torque-rich, and extremely clean BlueTEC diesels, and enjoying highway milage in the mid-to-high 20s in your 7-passenger, 5,000-pound-plus GL320 BlueTEC SUV bruiser, or mileage solidly in the 30s on your posh E320 BlueTEC, you could have the service techs top off the urea every time you get the oil changed. I'm just sayin'. Seven gallons in 10,000 miles sounds a small price to pay for ultra-clean emissions and at a reported cost of $7.50 per gallon for the urea, it doesn't sound like a cost that's out of bounds for the average Mercedes owner.

Diesel has an uphill battle here in the Unite States, but with our open ear and open minds, perhaps U.S. drivers will open their driveways again to the notion of, say, a VW Jetta that can get 58.85 mpg in the right hands. Diesel is not THE answer, of course. But I think it's one small part of the solution, and I hope it gets a fair shake this time. Diesel got killed the last go-round by the clap-trap GM Olds 350 diesel. Let's hope it doesn't get killed this time around by misinformation and knee-jerk headlines.

I'm Colin Mathews, and I approve of this message. Haters, get your pens and keyboard ready.--Colin Mathews

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From the city where SEMA is soon to go down, Audi today reports that its fleet of 23 diesels (Q7, Q5, A4, and A3) will soon roll into Las Vegas to complete about three-quarters of the Audi Mileage Marathon. The fleet of 23 vehicles, driven by leadfoot journalists and Joe and Jane Q. Public alike, started its journey in Manhattan on Oct. 6 and has been winding through the country ever since. After braving the desolate heat of Death Valley, the group will complete its journey in Santa Monica, Calif., this Sunday.

The story here is mileage. And it couldn’t come at a better time, as German automakers face an uphill struggle to change American perceptions about diesel fuel and engines. Due to tax incentives in much of Europe, diesel has been the cheapest fuel for decades there, and that has resulted in German engineers’ extensive development and refinement of the sparkless internal combustion engine. No longer smoky, clattery beasts of burden suitable only for trucks, in Europe diesels grace everything from S-Class Benzes to BMW’s new 7 Series Q ship. They are eager to spread this technology to America, but higher prices for complex engines on top of higher prices for diesel fuel in America are considerable obstacles.

Enter massive PR efforts like the Mileage Marathon. How does a best average of 29.40 mpg from the 5,000-plus-pound Q7 SUV sound? That includes crossing the rocky mountains (nearly 11,000-feet mountain passes), bumper-to-bumper slogging through Manhattan, and power-sapping 86-degree weather approaching Vegas.

But the Q7 is actually the worst mileage news. The new Q5 SUV with the same 3.0-liter TDI V-6 (240 hp, 369 pound-feet) rang in with a best of 37.94 mpg. The fleet new A4, again with the 3.0 TDI (369 pound-feet has got to be fun in this tidy sedan), netted up to 44.38 mpg. And the well-received A3, with a 2.0-liter TDI shared with the Volkswagen Jetta TDI, soared up to 47.04 mpg.

Last but not least, Audi touts this quartet of diesels as the cleanest in the world. New technology in the form of particulate filters and SCR (selective catalytic reduction) have eliminated the soot from diesel exhaust pipes, as well as turning much of the toxic nitrogen oxide into water vapor and harmless nitrogen gas, respectively. Audi apparently has gone the extra emissions mile with its new-for-’09, 50-state-compliant TDI engines, which already comply “with the Euro 6 standard not scheduled to come into force until 2014.”

Would you consider buying a new clean diesel from BMW (3 Series, X5), Mercedes (E320 BlueTEC, ML320 BlueTEC, R320 BlueTEC, GL320 BlueTEC), Audi, or VW (Jetta TDI clean diesel)? Are these mileage marathons inflated hype from PR departments, or do they strike you as legit proof of diesel’s superior economy? We know that our loquacious blog commenter, Ed, is all about the diesel. And I claim my own bias in favor of the diesel’s efficiency, longevity, and megatorque. What say you readers, enthusiasts, and automotive consumers?--Colin Mathews

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Motor Trend announces Subaru's redesigned Forester sports-utility vehicle as its pick for the coveted SUV of the Year award. Editor in Chief Angus MacKenzie summed up the winning vehicle's merits by stating, "The Subaru Forester is the SUV for our times."

Even prior to this announcement, Subaru's freshly redesigned Forester sales were up 32 percent over last year. While the restyle has taken what was once a stridently different SUV into the waters of a gentler, softly styled tall wagon demographic, all of the Subie techno-prowess (horizontally opposed engine, low center of gravity, asymmetrical all-wheel drive) and rugged functionality remain. So maybe it's not a vehicle just for Martina Navratilova and earth-day supporters anymore, but Subaru seems to have carefully blended the funky last-gen attributes with styling and features (a wheelbase stretched by 3.6 inches) that can pull in a much broader customer base. Not to mention a base price some $1,200 cheaper than the outgoing model, starting at $19,995. The SUV for our times, indeed.

In selecting the winner for their award, Motor Trend's editorial staff wrung a collection of 13 new-for-'09 SUVs through exhaustive driving test on-road, off-road, and at the test track. While comparisons are inevitable in a test of this type, Motor Trend is careful to point out that SUV of the Year is not a comparison test. Rather, every vehicle is judged on three criteria: superiority (engineering, design, utilization of resources), significance (its impact on the market), and value (what buyers get for their money versus the competition). Subaru won the competition by unanimous decision.

Said MT Technical Director Frank Markus, "the current range of engines offer a good balance of high performance or reasonable fuel economy, and the upcoming diesel will greatly increase the Forester's efficiency." In a rapidly changing market, the big, thirsty SUVs of yesteryear are losing relevance as tidier vehicles like the Forester take their place. Markus underscores this point, stating "the Forester is well positioned to deliver the all-wheel-drive traction, square-back light-duty hauling capability and high-eye-point seating customers enjoy in a far more efficient package."

$19,995 for all-wheel drive, five-star NHTSA crash ratings, and the kind of efficiency and versatility Americans demand. Good job, Subaru, and good call, MT.--Colin Mathews

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When it comes to diesels and hybrids, BMW seems to have its green gambits covered. Last week, the automaker handed us the keys to its new diesel 3 Series for an Alpine drive, which we'll detail for you soon. At the prior week's Paris auto show, it showed the ActiveHybrid 7 Series sedan it plans to put on sale late next year.

But what about a diesel hybrid? It sounds like the Holy Grail for fuel economy, combining two great fuel-saving technologies into one package. Indeed, Volvo's promising to put it into practice as soon as 2012. BMW, though, sees some temptation and lots of dollar signs in combining diesel engines and hybrid motors.

Putting the two together is an "interesting combination," says Wolfgang Mattes, who's in charge of getting BMW's diesels ready for sale in the United States. A diesel hybrid could boost fuel economy over a gas-only engine by 10 to 15 percent.

However, BMW sees more potential by boosting the efficiency of its diesel engines alone. Even from the current state of the art, they "can optimize another 15 to 20 percent, just from existing diesels," Mattes says, through eight-speed transmissions, reductions in friction and the like.

The essential problem with combining the two, he notes, is cost. Hybrids and diesels have similar cost disadvantages to plain old gas-powered engines--and putting them together might only work on a high-end vehicle where the cost would be a smaller fraction of the purchase price.

While BMW expands both hybrids and diesels across its lineup, "all options are on the table," says Mattes; even a Z4 powered by diesel isn't out of the question.

Though its lineup is canted toward diesels--nearly half its sales in Europe are oil-burners--BMW is pursuing hybrids at the same time. "There is a segment where hybrids make sense and a bigger segment where diesels make sense," Mattes says.

Interestingly, BMW's hybrid technology is getting help from its BMW-Sauber F1 team, says Markus Duesmann, Director of Powertrain Development for BMW-Sauber. The race team's new KERS--for "kinetic energy recovery system"--uses F1's astonishing braking forces to charge batteries that can be discharged up to once per race lap for an instant burst of power, one that can net critical seconds overall in a Formula 1 race. The team will use it in its 2009 season cars.

Sauber in the past helped BMW engineer the carbon-fiber roof found on the current M3. Could the race team's hybrid tech ever find its way into roadgoing BMWs? "It would be ideal for an M car," Duesmann says.

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Somebody must've spilled a drum of ULSD at AutoWeek's headquarters this morning, because we were graced by not one, not two, but three back-to-back articles singing the praises of Rudolf Diesel's oil burner. All well written and quite pointed, there was a stinging criticism of Ford's refusal to bring its passenger car diesels to the United States, a summary of Japan's gradual embrace of the diesel, and a drive/critique/tease of Subaru's new boxer turbodiesel set to come stateside (maybe) sometime after 2010.

Denise McCluggage excoriates Ford's Mark Fields' lack of leadership, calling him "a wuss." She sat through a recent Ford briefing on new drivetrains, claiming she endured 45 minutes of "droning before 'diesel' was mentioned, and then only in relation to trucks." She has a hard time understanding why Ford simply listens to market surveys and relies on hastily assembled PowerPoint presentations that claim low public opinion for diesel passenger cars. She believes that Ford should show some guts and lead, bringing its 65 mpg diesel Fiesta to America rather than letting Volkswagen, Audi, BMW, Honda/Acura, and perhaps Subaru lead the diesel charge and then playing me-too if those ventures succeed.

Next up, Dino Dalle Carbonare explains that even notoriously anti-diesel Japan is getting in on the sparkless bandwagon. Despite very slow sales of Mercedes E-Class CDI diesel since its intro in Japan in 2006, and a 2005 Tokyo ban on diesel passenger cars to limit city pollution, Nissan just introduced its new X-Trail 20GT with a 2.0-liter turbodiesel four. With this powerplant, the X-Trail is the first vehicle to meet Japan's new emissions standards (supposedly the strictest in the world) going into effect October '09. This engine also yields 30 percent better economy than the X-Trail's gasoline version (36 mpg vs. 27), and combined with diesel that sells for about 20 percent less than gasoline in the Japanese market, Nissan believes this compelling economic argument will force Japanese buyers to take a second look at diesel vehicles. Honda apparently feels the same way, and it is bringing a diesel to the Japanese market in '09.

The final piece of Autoweek's diesel triple-threat is Natalie Neff's article on the Subaru Boxer 2.0-liter turbodiesel, for sale in the European market in multiple models and just added to the European Forester SUV line with a six-speed manual for '09. With power numbers very similar to VW's 2.0 TDI unit (145 horsepower, 258 pound-feet), the Boxer is unique in that its horizontally opposed design eliminates the need for space-robbing balance shafts, the exhaust routing enables turbo location extremely close to the exhaust valves minimizing thermal losses, and the whole project marks the very first horizontally opposed turbodiesel engine for a production automobile. Neff claims the Forester with this diesel "never feels short of breath," and praises its smooth and quiet operation. Speaking to this engine's possible appearance in Subaru's North American lineup, she reports that Subaru says "we shouldn't expect it before 2010."

Disclaimer: Clearly, I am biased. I switched from my dream ride, a 1991 Toyota MR2, in favor of a crusty 300,000-mile Benz diesel wagon two years ago--not sexy, lean, or mean, but a relic from diesel's last heyday in America. Weekend work to get this 3,900-pound beast from rough to running has given me extreme respect for German engineering and appreciation for the longevity and durability of the diesel engine. Parts like $470-a-piece self-leveling rear shocks have kept me in local junkyards scavenging for $20 replacements to keep it all in working order. But to me, the icing on this rusty cake is the old Benz engine's ability to run on just about any oil you can throw at it, most specifically used vegetable oil. To prove a point about recycling used vegetable oil as a clean-burning alternative to ULSD, I'm traveling from Atlanta to L.A. in December on nothing but used veggie oil. And while I'm out in L.A., I'm finally getting the crusty, tri-color wagon a fresh coat of paint at a considerable discount.

Gas prices and economic woes are forcing automakers and backyard mechanics across the country (and the world) to consider new ways of powering automobiles. Diesel's resurgence is an interesting chapter in the quest for greater fuel economy, and with VW and Audi having set some mighty impressive fuel economy records as of late, the battle between gas/electric hybrids and ultra-efficient clean diesels has gone yet another exciting round.

What's your take? Should a cash-strapped Ford take a risk and bring passenger car diesels to America? Have you ever owned or driven a diesel, and if so, how would you describe your experience? Finally, do you think VW, Audi, BMW, Subaru, and Honda's diesels will change American opinion regarding the diesel, or is this popular-in-Europe engine a poor fit for American drivers?--Colin Mathews