BMW X5d diesel SUV

It's not that BMW is trying to get you into a diesel SUV, but... the car BMW loaned us for a week's test was an icebox-white X5 xDrive35d (they like long, unwieldy names at BMW) with the words "Efficient Dynamics" emblazoned in six-inch-high bright blue letters on both sides.

Well, yes, okay, we understand, but did you also have to have an even larger underlay, in white, stuck-on letters, that said, "Efficent"? And what about the smaller advertising on the rear flanks that proclaimed you can get 585 miles per tank of diesel fuel? All right. We've got it. (By the by, cars that end up with customers don't have the gaudy ads on the sides, but I suppose that if you really wanted them, BMW would slap them up there right quickly.)

What BMW has wrought with this diesel SUV is to bring American customers into the long-established European custom of driving fuel-efficient diesel vehicles. It's an interesting tack, mainly because diesels -- long thought of as noisy, slow and smoke-spewing -- are, in the modern idiom, none of those.

Yes, there is a slight bit of clatter from the X5's three-liter inline six-cylinder diesel at startup, but it quickly goes away and just sounds, more or less, like a normal gasoline engine.

So we'll get the techo stuff out of the way up front: current diesel engines, like the one in the X5, are called "clean diesels" because they don't rumble down the street, belching clouds of dirty black smoke, like all those big city buses we grew up with.

There's a more exhaustive explantion here, but suffice to say that the BMW X5 diesel uses a solution of urea called AdBlue to make things cleaner at the back end of the exhaust system.

Keep in mind, however, that BMW also markets two other versions of the X5, both powered by gasoline engines -- a three-liter conventional six; and a 4.8-liter V8. The diesel version, with a base price of $51,200 is about $4,000 more than the smaller gas-engined car and some $5,000 less than the V8 model. (While our car started life at $51,200, it ballooned to nearly $66,000 with more than $12,000 worth of add-on packages, including $1,200 for the "head-up display," which is an orange-lighted digital speedometer that appears, ghostlike, in the windshield. Is this really worth $1,200?)

Once you're inside the X5 diesel, however, you'll find it doesn't feel much different than the gasoline car. It has the requisite comfort, wrapping you in thick leather (thick is a theme here -- the steering wheel is a beefy monster of a thicko), steering wheel controls, zillion-speaker audio, air-in-all-directions heat and cold, and enough insulation to isolate you from all the diesel noise you thought you were going to hear, but won't, even if the windows are down.

What I found striking about this car were some of the esoteric design tricks. I liked the two-piece tailgate -- man, is that a throwback to 1960s era American wagons. The bottom half, when unfolded, is 15 inches deep, big enough to use as an extra shelf for, well, tailgate parties at the ballpark.

There's a lovely, great panoramic glass sunroof that goes sailing back forever (or, at least, past the front row people). In the center of the rear seat, you can lower the arm rest and find a folded-up cloth ski bag, so those muddy, wet skis won't muck up the inside of your SUV. (The assumption, left unsaid, is that people who buy BMWs are the people who can afford to go skiing. Just an aside.)

There were, however, a few irritating design flaws. The car came equipped with running boards, but they were too high -- they were just about at a level with the floor, so when you're trying to get out, your calf scrapes down along the running board. Either lose the boards or lower them. After 15 minutes of searching, I gave up on trying to find a latch for the glove box. (I later found it, only by doing a Google search and learning that I wasn't the only one looking for this elusive button.)

Then there's BMW's long-hated iDrive control system for navigation, audio and other esoterica. Word is that it's going to be revamped in next year's X5. I wasn't driving next year's X5. Complaining about the iDrive is like shouting at a blank wall -- but, once again: simplicity would suffice.

On the road, the X5 diesel is everything you'd expect in a big SUV from BMW. It's fast (zero to 60 in under 8 seconds, says the factory), the ABS brakes stop the car quickly, despite its weight of more than two and a half tons, and it will haul you and yours serenely for long distances at (diesel, once again) good mileage.

Ultimately, it comes down to this, if you're dithering between gas and diesel: If you want different, and if you especially want low-end torque, you'll want the diesel. It's strong, generally reliable and it's more efficient.The downside (if you want to call it that) is that with diesel is that there are fewer fueling opportunities -- there are more gas pumps than diesel pumps. On the other hand, right now (and keep in mind that fuel costs fluctuate wildly, as we've all seen) diesel costs slightly less: a recent check with AAA showed that the national price for regular-grade gasoline was $2.67 a gallon, $2.55 for diesel.

It's up to you.

SPECIFICATIONS:

2009 BMW X5 xDrive35d; front engine, all-wheel drive five-door SUV.

Price: test model, $51,200 (Base price: $65,620)

Power train: 3-liter inline six-cylinder 265-horsepower diesel engine. Six-speed automatic transmission, with manumatic function.

Curb weight: 5,225 pounds.

Seating capacity: seven.

Fuel consumption : 19 mpg, city; 26 mpg, highway.

Fuel tank capacity: 22.5 gallons.

Length: 191.1 inches; width: 76.1 inches; height: 69.5 inches; wheelbase: 115.5 inches.

Warranty: four years/50,000 miles.