As a teenager in the mid-1970s, I remember (along with Levi's corduroys, sugar-sweet top 40 songs and my "Chachi"-style hair) our neighbor's cream yellow Mercedes-Benz 240D. "Wow, a Mercedes-Benz," was my first thought when I went over to check out the car as it sat in their driveway. But my wide-eyed enthusiasm was soon quashed when I looked through the windows and saw the taxi cab-plain interior with its simple upholstery, manual windows and general lack of luxury trimmings. And I was equally disappointed when I saw my neighbor drive it away. When the Benz was cold, black smoke would come out of the tailpipe and the engine sounded as if it was percolating that morning's coffee. And as I learned after reading a magazine road test, it was also agonizingly slow, taking something on the order of 18 seconds to get to 60 mph. What I didn't realize about the diesel Benz was that it had the durability of an anvil and the fuel economy of a motorcycle. But those important advantages weren't as readily apparent as the aforementioned and more obvious disadvantages.
Unfortunately, nearly three decades later, most folk's impressions of diesel automobiles mirror those that were prevalent during the K.C. and the Sunshine Band days. Back then, people were more concerned with fuel efficiency than performance, and they were willing to make sacrifices to get better mileage. In fact, most Mercedes-Benz models sold in the late 1970s and early 1980s were diesels, ranging from the entry-level 240D through the senior, luxurious S-Class 300SD. With the aid of a turbocharger in the more expensive Mercedes models, the diesel's performance approached respectable levels, but the clattering cacophony and occasional emission of sooty exhaust didn't help to maintain a fan base once the threat of gasoline shortages and relatively high gas prices subsided. Still, right on up throughout the 1990s, Mercedes fielded an increasingly refined diesel version of its midsize E-Class sedan. But this model was never very popular in an era of cheap and plentiful gasoline, as it didn't offer any apparent advantage to the average consumer.
As they say, history repeats itself, and now with gas prices at an all-time high, interest in diesels is once again on the rise. Only now, it's not as easy to tell if a Mercedes-Benz is diesel-powered, whether at rest or running down the road.
If you walk around the 2005 E320 CDI when it's parked, the only giveaway that this E-Class sedan is in fact a diesel is a "CDI" badge on the right side of the trunk lid. Even the alloy wheels are the same as those of its gas-fueled sibling. Inside the cabin, apart from a tach with a noticeably lower redline, everything is the same — the abundance of highly polished wood, the perforated leather upholstery and the general feeling of luxury will be familiar to anyone who's occupied the cabin of a 2003 or 2004 E320.
When you fire up a cold diesel engine, you're supposed to wait for the glow plugs to preheat the combustion chambers (so that the engine will start up more quickly). An indicator light (shaped like a squiggly line) in the instrument panel shows you if this is taking place. But we never had to wait so much as a nanosecond, as the light went out immediately — we just twisted the key and it fired up immediately with a well-muted clatter. Of course, here in L.A., it doesn't get too cold; we imagine that in the dead of a northeast winter, one might have to wait a moment or two for the glow plugs to do their thing before waking up the oil burner for the morning's commute.
Part of the reason for the quick firing is the CDI technology. CDI stands for Common-rail Diesel Injection, the state-of-the-art fuel delivery system that promotes smoother, cleaner and quieter diesel operation. The CDI system accomplishes this via a high-pressure fuel delivery that also injects a small amount of fuel into the cylinder just before the main charge is sent in. This starts the fuel burn cycle so that when the main charge is ignited, the action inside the combustion chamber is more progressive, making for a broader power band, less noise and vibration and a more complete burning of the diesel fuel.
With its peak torque of 369 pound-feet (horsepower is 201) available as low as 1,800 rpm, the sedan's turbocharged 3.2-liter inline six supplies spirited performance — provided you've selected the proper mode for the five-speed automatic transmission. One has a choice of two modes for the tranny: "comfort" (which starts the car out in second gear and changes gears earlier, thus making for more gentle acceleration and better fuel economy) and "sport" (which starts the car out in first and holds each gear longer, making for more eager acceleration).
One of Edmunds.com's senior executives took the Benz for a spin and was disappointed as he thought the car was a little sluggish off the mark and around town. He didn't realize that the transmission was in the comfort mode, as the small round button with the "C/S" on it is easy to miss. Of course, most of the road test staff drove the car with the tranny in sport mode which gives the car a wholly different personality at the expense of ultimate fuel efficiency. The torrent of torque is quickly apparent as the CDI just leaps away from the lights, the jetlinerlike thrust preceded by a brief chirp as the rear tires and traction control system deal with the incredible low-end power. Acceleration times at the track confirmed our seat-of-the-pants impressions, with the oil-burning Benz hitting 60 mph in 7.3 seconds and running through the quarter-mile in just 15.5 ticks of the stopwatch.
Cruising and passing on the freeway were equally effortless affairs, with the low-revving engine just loafing along at a 75-80-mph cruise. The driving experience is typical E-Class, meaning composed handling along with a firm but comfortable ride. The electronically assisted brakes felt more natural than in past E-Class cars we've driven, and hauled the car down from 60 mph in a very respectable 121 feet. Our track tester did note that there was some brake fade when the CDI was subjected to the back-to-back panic stops that are part of our rigorous testing procedure, but still rated their performance as "good" overall. At the hands (and feet) of our road test staff, the E320 CDI averaged around 26 mpg against EPA estimates of 27 city/37 highway. We have no doubt that we could have averaged a cool 30 mpg had we selected the transmission's less thirsty "comfort" mode and resisted stepping into the turbo boost at every opportunity.
OK, so this new E-Class turbodiesel is pretty fast and gets great mileage, but does it smell and belch out soot as in the "good old days"? No and no. We're happy to say that the CDI never offended us in either fashion; it's simply amazing how unlike the old diesels this strong performer is. We listened for the telltale clatter that signifies compression ignition, but it was well muted and only stood out when the car was started up in our underground parking structure (where the sound would reverberate off of other parked cars and the concrete walls). Once we were out on the street with the windows up, the sound was different, but not louder than a gasoline-powered E-Class sedan. Perhaps the most obvious sign that there was a diesel under the hood was an occasional shudder when the engine was shut off.
One staffer, however, felt that some Americans (who are used to gas engines) might find the Benz's diesel a bit noisy when the car is at a standstill or driving through city traffic with the windows open. But that's a very small price to pay for a car that offers 40-percent better mileage than its gasoline counterpart, equal if not better performance and the promise of incredible longevity (diesel engines are known to last for 300,000 or more miles). So that's the good news. The bad news is that, for now, the E320 CDI is a "45-state" car, meaning that it doesn't meet the more rigorous emissions standards of California, Maine, Massachusetts, New York and Vermont. With the promise that the U.S. will soon get the cleaner-burning (low-sulfur content) diesel fuel now used in Europe, we're keeping our fingers crossed that the E320 CDI will eventually be available to buyers in all 50 states.
Unfortunately, nearly three decades later, most folk's impressions of diesel automobiles mirror those that were prevalent during the K.C. and the Sunshine Band days. Back then, people were more concerned with fuel efficiency than performance, and they were willing to make sacrifices to get better mileage. In fact, most Mercedes-Benz models sold in the late 1970s and early 1980s were diesels, ranging from the entry-level 240D through the senior, luxurious S-Class 300SD. With the aid of a turbocharger in the more expensive Mercedes models, the diesel's performance approached respectable levels, but the clattering cacophony and occasional emission of sooty exhaust didn't help to maintain a fan base once the threat of gasoline shortages and relatively high gas prices subsided. Still, right on up throughout the 1990s, Mercedes fielded an increasingly refined diesel version of its midsize E-Class sedan. But this model was never very popular in an era of cheap and plentiful gasoline, as it didn't offer any apparent advantage to the average consumer.
As they say, history repeats itself, and now with gas prices at an all-time high, interest in diesels is once again on the rise. Only now, it's not as easy to tell if a Mercedes-Benz is diesel-powered, whether at rest or running down the road.
If you walk around the 2005 E320 CDI when it's parked, the only giveaway that this E-Class sedan is in fact a diesel is a "CDI" badge on the right side of the trunk lid. Even the alloy wheels are the same as those of its gas-fueled sibling. Inside the cabin, apart from a tach with a noticeably lower redline, everything is the same — the abundance of highly polished wood, the perforated leather upholstery and the general feeling of luxury will be familiar to anyone who's occupied the cabin of a 2003 or 2004 E320.
When you fire up a cold diesel engine, you're supposed to wait for the glow plugs to preheat the combustion chambers (so that the engine will start up more quickly). An indicator light (shaped like a squiggly line) in the instrument panel shows you if this is taking place. But we never had to wait so much as a nanosecond, as the light went out immediately — we just twisted the key and it fired up immediately with a well-muted clatter. Of course, here in L.A., it doesn't get too cold; we imagine that in the dead of a northeast winter, one might have to wait a moment or two for the glow plugs to do their thing before waking up the oil burner for the morning's commute.
Part of the reason for the quick firing is the CDI technology. CDI stands for Common-rail Diesel Injection, the state-of-the-art fuel delivery system that promotes smoother, cleaner and quieter diesel operation. The CDI system accomplishes this via a high-pressure fuel delivery that also injects a small amount of fuel into the cylinder just before the main charge is sent in. This starts the fuel burn cycle so that when the main charge is ignited, the action inside the combustion chamber is more progressive, making for a broader power band, less noise and vibration and a more complete burning of the diesel fuel.
With its peak torque of 369 pound-feet (horsepower is 201) available as low as 1,800 rpm, the sedan's turbocharged 3.2-liter inline six supplies spirited performance — provided you've selected the proper mode for the five-speed automatic transmission. One has a choice of two modes for the tranny: "comfort" (which starts the car out in second gear and changes gears earlier, thus making for more gentle acceleration and better fuel economy) and "sport" (which starts the car out in first and holds each gear longer, making for more eager acceleration).
One of Edmunds.com's senior executives took the Benz for a spin and was disappointed as he thought the car was a little sluggish off the mark and around town. He didn't realize that the transmission was in the comfort mode, as the small round button with the "C/S" on it is easy to miss. Of course, most of the road test staff drove the car with the tranny in sport mode which gives the car a wholly different personality at the expense of ultimate fuel efficiency. The torrent of torque is quickly apparent as the CDI just leaps away from the lights, the jetlinerlike thrust preceded by a brief chirp as the rear tires and traction control system deal with the incredible low-end power. Acceleration times at the track confirmed our seat-of-the-pants impressions, with the oil-burning Benz hitting 60 mph in 7.3 seconds and running through the quarter-mile in just 15.5 ticks of the stopwatch.
Cruising and passing on the freeway were equally effortless affairs, with the low-revving engine just loafing along at a 75-80-mph cruise. The driving experience is typical E-Class, meaning composed handling along with a firm but comfortable ride. The electronically assisted brakes felt more natural than in past E-Class cars we've driven, and hauled the car down from 60 mph in a very respectable 121 feet. Our track tester did note that there was some brake fade when the CDI was subjected to the back-to-back panic stops that are part of our rigorous testing procedure, but still rated their performance as "good" overall. At the hands (and feet) of our road test staff, the E320 CDI averaged around 26 mpg against EPA estimates of 27 city/37 highway. We have no doubt that we could have averaged a cool 30 mpg had we selected the transmission's less thirsty "comfort" mode and resisted stepping into the turbo boost at every opportunity.
OK, so this new E-Class turbodiesel is pretty fast and gets great mileage, but does it smell and belch out soot as in the "good old days"? No and no. We're happy to say that the CDI never offended us in either fashion; it's simply amazing how unlike the old diesels this strong performer is. We listened for the telltale clatter that signifies compression ignition, but it was well muted and only stood out when the car was started up in our underground parking structure (where the sound would reverberate off of other parked cars and the concrete walls). Once we were out on the street with the windows up, the sound was different, but not louder than a gasoline-powered E-Class sedan. Perhaps the most obvious sign that there was a diesel under the hood was an occasional shudder when the engine was shut off.
One staffer, however, felt that some Americans (who are used to gas engines) might find the Benz's diesel a bit noisy when the car is at a standstill or driving through city traffic with the windows open. But that's a very small price to pay for a car that offers 40-percent better mileage than its gasoline counterpart, equal if not better performance and the promise of incredible longevity (diesel engines are known to last for 300,000 or more miles). So that's the good news. The bad news is that, for now, the E320 CDI is a "45-state" car, meaning that it doesn't meet the more rigorous emissions standards of California, Maine, Massachusetts, New York and Vermont. With the promise that the U.S. will soon get the cleaner-burning (low-sulfur content) diesel fuel now used in Europe, we're keeping our fingers crossed that the E320 CDI will eventually be available to buyers in all 50 states.
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