Programming destinations into the navigation system is equally cumbersome, as it requires lots of fiddling about with the multidirectional button cluster on the lower right of the screen. Letters for place names or points of interest must be selected and entered one at a time, a procedure that is lengthened further by the navigational system's sluggish processor (fiber-optic communications network appears to offer little help), which has a habit of stopping for a long, hard think between menu levels and sometimes between individual letter entry.
With a destination finally entered, we found it can take another 10 to 15 seconds for the system to come up with its route. After all this thinking time, one would assume that the routes and the voice guidance would be pretty accurate, but, alas, we found them not so. Having endured the intensely annoying staccato voice-guidance lady (in-FOUR-hundred-YARDS-turn-RIGHT-right-AND-then-TURN-RIGHT-AGAIN) all the way to our expected journey's end, we found we were nowhere near our destination. Upon arriving in Los Angeles after more than eight hours of driving, the system told us that we had arrived at our destination--the Beverly Hilton--at 9876 Wilshire Boulevard. In reality, we were somewhere in the mid-11,000s on Wilshire--more than a mile away from where we wanted to be.
The salvation of the E320's navigation system is the white-on-black monochrome LCD display built into the speedometer, which is perhaps the most useful onboard tech feature of the entire car. In navigation mode, this display supplements the main in-dash screen by showing turn arrows, distances, and road names throughout the course of the journey, vastly improving the waypoint-finding experience. The in-speedometer display is also a very useful means of checking on the current satellite radio station, trip info, and--as we found in drive to L.A.--gas mileage.
The 2007 E320 BlueTec comes with Mercedes' premium 12-speaker 420-watt Harman Kardon digital surround-sound audio system, which is hooked up to a six-disc in-dash changer capable of playing CDs and MP3 and WMA discs. With 7.1 surround-sound architecture, the system produces a clean, crisp sound with deep bass notes and good separation for music with wide dynamic range such as that found on Sirius' Symphony channel. Also to our liking was the system's ability to display full tag information for homemade digital-audio discs, and the auxiliary input jack secretly located in the glove box.
Like the E550 and the S550, the Mercedes E320 BlueTec does come with the option of hands-free calling. However, it is Mercedes' proprietary take on this technology (rather than the open-standard Bluetooth), which supports only a limited number of cell phone handsets and requires users to buy a separate adapter module from the dealer for an extra $350. In our opinion, that's about $350 too much if you've just laid down more than $50,000 for a luxury car.
Other nice-to-have cabin tech included in our tester's Premium II package included a power rear sunshade, heated front seats, and bi-xenon headlamps with active curve illumination.
Under the hood
The 2007 E320 BlueTec is the first car to reach the U.S. with a BlueTec engine, although contrary to DaimlerChrysler's claims at the 2006 Detroit Auto Show that the car would meet emissions standards for all 50 states, the car is not for sale in the five states (including California) with the strictest emissions standards. BlueTec diesel engines make use of a number of components in the exhaust stream that serve to treat the engine's emissions before they are released into the air. These comprise an oxidizing catalytic converter, a particulate filter, an advanced "denox" storage converter, and a Series Catalytic Reduction (SCR) catalytic converter, which adds a reducing agent to the exhaust stream in diesel cars to reduce harmful nitrogen oxides into less noxious components. In addition, the exhaust-stream technology, the E320 runs on ultralow sulphur diesel, which is available at a limited--but growing--number of gas stations across the country. To help its drivers out, Mercedes provides an online gas station locator on its Web site.
In the E320, the origin of all that treatable exhaust is a 24-valve V-6 aluminum block featuring electronically controlled ultrahigh-pressure common-rail direct injection. So much for all the theory, you say; how does it drive?
For a diesel-engine car, the 2007 Mercedes-Benz E320 BlueTec is remarkably quiet, especially on the highway. With that said, the engine does still emit a faint clattering sound, particularly noticeable at low speeds, which would send us directly to the nearest Mercedes dealer if we heard it on a new gasoline-engine E-class.
As with many diesels, the 2007 E320 BlueTec has bucket loads of torque, which is complemented by the assistance of a turbocharger. With 388 pound-feet available from 1,600rpm, the V-6 diesel rockets forward with a velocity reminiscent of that in the V-8 E550. One particularly notable feature of the driving experience in the E320 is the lightness of its power-assist rack-and pinion steering. Like the E550, the E320 BlueTec comes with a driver-adaptive seven-speed automatic transmission, which adapts to each driver's particular driving style. With our own personalized transmission and the ability to switch to Comfort mode, which starts the car from standing in second gear and delivered upshifts at lower rpms, we found the ride smooth and consistent.
Our Mercedes-Benz E320 BlueTec tester came with the $4,290 Premium II package, which gave us most of the car's advanced technology features including: DVD navigation, Sirius Satellite Radio, hands-free calling capability, a power rear-window sunshade, Bi-xenon headlights and the Keyless Go smart-key system. The only other options on our car were the electronic trunk-closer ($520) and a Barolo red paint job ($700). Added to the E320 BlueTec's base price of $51,550 and a $775 destination fee, the grand total for our test mule came to $57,835 all in.
The 2007 Mercedes-Benz E320 BlueTec marks a new chapter for diesel in the United States. With a comfortable cabin (albeit with some uninspiring tech), solid performance, and an astonishingly economical drivetrain, we think it will be a hit.