The Mercedes-Benz GL320 CDI could change the way Americans think about diesel. Mercedes certainly hopes so
If you want to drive a big SUV and get halfway decent mileage, you have a choice this year: hybrid or diesel. General Motors (GM) is the pioneer in big hybrid SUVs with new gasoline/electric-powered versions of its Chevy Tahoe (BusinessWeek.com, 3/3/08), GMC Yukon, and Cadillac Escalade. Meanwhile, Mercedes-Benz (DAI) and other German companies are coming out with a raft of attractive diesel SUVs, of which the new Mercedes GL320 CDI is a prime example. It is a roomy seven-passenger all-wheel-drive vehicle rated to average 20 miles per gallon (18 city/24 highway), one-third better than the Mercedes GL450, the most comparable gasoline-powered model.
Diesel, which accounts for about half of the European market, seems destined finally to gain popularity on this side of the Atlantic. It will account for only 3.6% of U.S. passenger vehicle sales this year (vs. 2.4% for hybrids), but J.D. Power & Associates expects diesel's share to rise to about 10% by 2015. Mercedes saw its U.S. sales of diesel-powered models increase by 81.2%, to 12,580, last year. Its diesel-powered products include M-Class, R-Class, and GL-Class SUVs, as well as an E-Class sedan (BusinessWeek.com, 6/30/06).
One of the big impediments to diesel's success is about to be removed. Current diesel SUVs can't be sold in states with stringent pollution standards, including California and New York. As of this fall, when '09 models come out, Mercedes diesels will burn clean enough to be sold in all 50 states for the first time. Later this year, BMW (BMWG) is unveiling its '09 X5 xDrive 35d, a diesel-powered version of its hot-selling X5 (BusinessWeek.com, 4/27/07), and Volkswagen (VLKAY) and Audi (NSUG) with a V-6-powered versions of the Touareg TDI and Q7 TDI, respectively. These new diesel SUVs will also qualify for sale in all 50 states, the companies say.
One big downside remains. Diesel—which historically cost less than regular gasoline—has been selling for around $3.70 per gallon lately, according to the American Automobile Assn., about 20¢ more than premium gasoline and 50¢ more than regular unleaded. The price of diesel may come down after the costly transition to clean-burning ultralow sulfur diesel is completed in 2010, but that's far from certain. High demand from China, India, and Europe, as well as a shortage of refinery capacity in the U.S., could all maintain upward pressure on prices.
Fuel price jitters aside, modern diesels are far more attractive than the loud, smoke-belching diesels of yesteryear. The GL320 CDI starts easily in cold weather. Outside the vehicle, the idling engine has a noticeable grumble, but during driving it makes no more noise than a gasoline engine. The 3.0-liter V-6 in the GL320 is rated at only 215 horsepower, but like other diesel engines it delivers far more torque (398 foot-pounds) than a comparable gasoline engine, giving it excellent towing power and surprisingly good acceleration.
To my eye, the GL's exterior styling is less attractive than that of Mercedes' more popular M-Class. The GL looks too square and panel-van-like for my taste. But it's a wonderful piece of machinery, with four-wheel independent air suspension with electronic damping, a unit body chassis made of high-strength steel, and Mercedes' usual full array of air bags and other safety gear.
If you don't want a diesel engine, there's the GL450. It comes with a 4.7-liter, 335-hp gasoline-powered V-8 as well as the same full range of standard equipment as the GL320 CDI, including 18-inch wheels, textured cloth upholstery, heated and power-adjustable front seats, a power-fold-down third row of seats, dual-zone automatic climate control, and a six-CD audio system. For speed demons, there's the even more glandular GL550, which comes standard with a 5.5-liter, 382-horsepower gasoline-powered V-8 under its hood, as well as 21-inch wheels and some unique exterior styling features. All GL models come with Mercedes' smooth seven-speed automatic transmission.
As you might expect, GL-Class SUVs are far from cheap. The GL320 CDI starts at $54,225, and the price mounts rapidly if you add upgrades such as Premium Package ($6,400 to $8,600), rear-seat entertainment system ($2,670), voice control ($550), and iPOD integration kit ($375). But it costs $2,500 less than the GL450, which starts at $56,725, and it's a bargain compared with the GL550 ($78,200).
Last year the GL-Class was one of Mercedes' hottest sellers, with sales up 40.6%, to 26,396, although growth has slowed to only 0.6%,or 3,773, in the first two months of this year. By contrast, Mercedes' overall U.S. sales were up 7.2%, to 36,839, in January and February, and M-Class SUV sales were up 32.1%, to 6,318.
Behind the Wheel
With three rows of seats and a maximum seating capacity of seven, GL-Class SUVs are ideal for carpooling. They have a cushier ride and are less sporty and fun to drive than five-passenger M-Class SUVs (BusinessWeek.com, 2/19/08), which have only two rows of seats and are about a foot shorter.
Like most Mercedes models these days, the GL-Class is no slug. I timed the GL320 CDI at a bit under nine seconds in accelerating from 0 to 60. That's slower than the GL450, which Mercedes says clocks in at 7.4 seconds, and a lot slower than the GL550, which does 0 to 60 in a mere six seconds. But the GL320 feels quicker than it is because diesel engines have so much low-end torque. (That's one reason Audi is coming out with diesel-powered versions of its TT sports car (BusinessWeek.com, 3/4/08).
The GL 320's cabin is elegant, with comfortable seats, excellent workmanship, and distinctive design elements such as grab bars that form the sides of the center console. Each side of the third-row seats can be raised and lowered independently at the push of a button. The power rear hatch also goes up and down automatically.
The rear-seat entertainment system has two screens built into the backs of the front seats, freeing up ceiling space for a big sunroof. But the DVD player is stowed under the second row seat, which is makes it hard to get at when you need to change discs. There also are no video screens for third-row passengers, a potential problem if you have lots of kids to keep amused.
GL-Class SUVs can tow up to 7,500 lb. and have reasonably good off-road capabilities, especially if you go with the optional adaptive air suspension, which allows you to raise ground clearance to over 10 in. The GL450 can be had with an off-road package with a modified air suspension system that allows you to raise ground clearance to 12 in.
Buy it or Bag It?
There are two big issues to consider before buying a GL320 CDI: the price of diesel and whether you really need a vehicle this big.
The GL320 CDI sells for an average of $63,907, according to the Power Information Network (PIN). If you can get by with five-passenger seating capacity, you can save money by going with the ML320 CDI instead, the diesel-powered version of Mercedes' M-Class SUV. It has the same engine and gets the same mileage as the GL320 CDI but costs about eight grand less.
If you really want a seven-passenger SUV, consider waiting until this fall, when you can also test-drive diesel versions of the BMW X5, VW Touareg (BusinessWeek.com, 2/23/07), and Audi Q7 (BusinessWeek.com, 12/8/06). The gasoline models of those rivals sell for less than the Mercedes, according to PIN, so the diesels may cost less, too. This fall, you also will be able to check out the '09 Cadillac Escalade Hybrid, which will probably be in the same price range as the GL320 CDI.
In the meantime, the Chevy Tahoe Hybrid is already on dealers' lots. It's less fancy than the GL320 CDI, starts at $53,295 with all-wheel drive and tons of standard equipment, is rated to average 20 mpg, and runs on regular unleaded gasoline.
Click here to see more of the 2008 Mercedes-Benz GL320 CDI.