Mercedes-Benz has been doing the big-vehicle, small-engine thing in the Old Country for years, selling V6-powered SL convertibles that wouldn't have a hope or prayer in the US market. And it isn't just its sporty offerings that are de-engined in Europe - its sedan engines are downsized across the pond as well. It's called the E250 Bluetec, and it takes advantage of the same 2.1-liter, turbo-diesel four-cylinder that we found so charming in the GLK250 Bluetec last year. The E250 also serves as a replacement for the lovable, V6-powered E350 Bluetec. We spent a week with the thriftiest E-Class to see if a small, four-cylinder was enough for a big Mercedes sedan in the US. Driving Notes - That 2.1-liter turbodiesel might not sound like a lot of engine, but its performance fits in well with the E250's brief as a comfortable and luxurious sedan. There's 195 horsepower available at 3,800 rpm, while 369 pound-feet of torque can be had between 1,600 and 1,800 rpm. Rear-wheel drive comes standard, though our tester was fitted with Merc's 4Matic all-wheel-drive system.

Mercedes-Benz has been doing the big-vehicle, small-engine thing in the Old Country for years, selling V6-powered SL convertibles that wouldn't have a hope or prayer in the US market. And it isn't just its sporty offerings that are de-engined in Europe - its sedan engines are downsized across the pond as well. It's called the E250 Bluetec, and it takes advantage of the same 2.1-liter, turbo-diesel four-cylinder that we found so charming in the GLK250 Bluetec last year. The E250 also serves as a replacement for the lovable, V6-powered E350 Bluetec. We spent a week with the thriftiest E-Class to see if a small, four-cylinder was enough for a big Mercedes sedan in the US. Driving Notes - That 2.1-liter turbodiesel might not sound like a lot of engine, but its performance fits in well with the E250's brief as a comfortable and luxurious sedan. There's 195 horsepower available at 3,800 rpm, while 369 pound-feet of torque can be had between 1,600 and 1,800 rpm. Rear-wheel drive comes standard, though our tester was fitted with Merc's 4Matic all-wheel-drive system.

The EPA rating on the MB's window sticker claims it will return 27 miles per gallon in the city and 42 mpg on the highway, for a combined 32-mpg rating. Our experience was slightly above the combined average, at about 34 mpg in mixed driving. There's some turbo lag here, but it's only truly intrusive when digging into the throttle at very low speeds. The 2.1 is a quiet, unobtrusive mill, that doesn't subscribe to any of the clattery diesel noises when cold and remains stealthily quiet while accelerating at freeway speeds. A seven-speed automatic is the sole transmission for the E250, and it is a peach. Smooth, barely perceptible upshifts are matched up with quick downshifts. Our tester featured a Mercedes sport package, which adds a unique set of 17-inch alloy wheels (the standard size offered on the E250), while lowering the suspension and adding a few aesthetic tweaks.

Still, the ride was comfortable, likely due to the relatively small wheels and higher sidewall of the tires. The E250 was smooth and comfortable over a variety of surfaces, only suffering from an overabundance of vertical motion, or porpoising, on undulating surfaces at higher speeds. 53,900, but can climb quickly from there. 2,800 for a Driver Assistance pack (adaptive cruise, blind spot monitoring, lane keeping and cross-traffic alert. Oddly, the Sport Pack is a no-cost option. The case for the E250 is hurt by its range of V6-powered, diesel-engined competitors. Both the BMW 535d and Audi A6 TDI are significantly more powerful for just a couple thousand dollars more than our tester's base price. The E250 is a compelling vehicle for a select group of buyers. Where the E350 and E550 are solidly in the sport sedan category, the E250 is not. It's quieter and smoother, making it a generally better car for those that aren't looking to get anywhere in a hurry. We like the fuel economy argument it provides, as well. All that said, its starting price and more powerful competitors hurt the appeal of the oil-burning Benz for just about anyone that doesn't place fuel economy as their number one priority.

That said, aside from General Motors and Mazda, car companies based in Detroit and Japan have shunned diesels, other than in pickup trucks. Ford says its EcoBoost direct-injection turbocharged system delivers fuel economy gains without the cost of cleaning up diesel emissions. Honda, at one point, thought about adding diesels to its lineup, but declined because of the cost of exhaust treatment systems such as BlueTec. Toyota and Ford have also put plenty of effort into hybrids. Hybrids present their own issues. Some have criticized them for not delivering the advertised fuel economy. Where does all this leave us? Mike Manley, chief executive of Chrysler's Jeep brand, told trade journal Automotive News. If you test drive the GLK or any other new diesels, you'll like the experience. They're quiet and smooth, with none of the engine clatter and rattle that turned off buyers in the 1980s. Smoke? Nope. After treatments like BlueTec take care of it, and particulates, and acid-rain-inducing oxides of nitrogen, too.