Test drive: 2007 Mercedes-Benz E320 BLUETEC

Whenever I write a blog post dealing with MPG, I will often get at least one email from the owner of a 10-to-20 year old Honda who regularly sees MPG figures in the mid-30s. The new diesel-powered Mercedes-Benz E320 is bigger, faster, more luxurious, and nearly twice as heavy as those old Hondas, yet it too sees MPG numbers in the low-to-mid 30s. That, my friends, is the beauty of diesel. In a little less than two weeks, the E320 will go on sale in 45 states for just $1,000 more than the similarly-equipped gasoline-powered E350. I, for one, can't wait to see the sales numbers.

The E320's on-sale date corresponds with the wide availability of ultra-low sulfer diesel fuel (ULSD) in the US. ULSD allows the use of catalytic converters that can clean up diesel exhaust even more. (The same goes for low-sulfer gasoline. All gasoline sold in California is low-sulfer, but the oil companies are resisting bringing it to all 50 states, citing higher refining costs. Wouldn't want those poor guys to go a quarter without setting an all-time profit record, now would we?) Mercedes wants to position themselves as the leader in diesel. Smart move -- once the floodgates open and more diesel cars become available, I think America and Canada will catch diesel fever in much the same way that Europe has. After all, if a big car that gets 20 MPG with a modest gas engine can get 30 to 35 MPG with a diesel, imagine what diesel can do for a small economy car that gets 30 MPG with a gas engine. If you're thinking 40 to 50 MPG, you'd be right.

The E320 BLUETEC will go on sale in all 50 states in 2008; there's still some legislative wrangling to be done. To meet the more stringent emissions standards in California, Maine, Massachusetts, New York and Vermont, the E320 relies on an additive called AdBlue. The EPA is still trying to decide the best way to ensure that owners refill their AdBlue tanks as needed. This may only be a temporary issue: Honda, a relative newcomer to the diesel scene, is working on a system that will meet California standards with no additives. For those who are curious about the technical side of diesel emission control, check out my article on How Mercedes-Benz BLUETEC Works, which covers both 45- and 50-state versions of the car.

Come Wednesday morning I'm off to Montreal to drive a whole mess o' new Audis, including the S6, S8, A4 cabriolet, S4 cabriolet, and V6-powered version of the Q7 SUV. Man, I love this job! -- Aaron Gold

More diesel test drives:

• 2006 Volkswagen Jetta TDI
• 2005 Volkswagen Passat Wagon TDI
• 2005 Mercedes-Benz E320CDI
• 2004 Volkswagen Jetta TDI test drive

Photo © Aaron Gold -- Check out our review of the gasoline-powered 2007 Mercedes E350 and E550 and our 2007 E-Class photo gallery