BMW's diesel X5 handles great but is a bit of a letdown

FREMONT, Ohio -- Three surprises from BMW's 2009 diesel-power X5 crossover SUV, on sale since December.

The drivetrain was disappointing, less satisfying than the diesel 3 Series sedan with this engine.

The wide-tread tires that come with the optional Sport package ($3,700) did not ruin the ride. In the past, opting for Sport guaranteed your X5 would be unlivable except on new asphalt. Now, it means it claws through tight corners the way you imagine a BMW should.

The stability/traction control system, tuned by many automakers (especially German brands) to intrude too much, seemed reliable and restrained in 600 miles of slush, snow and freezing rain. It left one musing on the X5's behavior instead of white-knuckling, squinty-eyed, down the turnpike.

BMW launched the X5 crossover SUV as a 2000 model and improved it considerably since then. It was updated for 2007, and diesel was added for '09.

Perhaps it was inevitable that the X5 xDrive35d was a letdown after the 335d sedan (Test Drive, Nov. 21) that was well north of terrific.

What kept the X5 with the three-liter, six-cylinder diesel getting the highest grades:

• Lag-and-lunge. A lot like the Mercedes-Benz ML 320 BlueTec diesel (Test Drive, Nov. 28). You can take off smoothly or quickly, not both.

BMW's unique two-turbo system should have eliminated that — and did on the 335d sedan.

X5's drivetrain tuning and gearing aren't the same as the sedan's, but nobody else has complained, says BMW spokesman Matthew Russell.

• Noise. The clatter could give you pause, if you're new to diesels. Inside, the engine sound is more a reassuring grumble, but all in all there's more of it than in the 3 Series diesel sedan.

X5 has less noise insulation, especially underneath where an SUV needs extra clearance for navigating bad roads and no roads, Russell says.

• Warning light. Not what you want in the middle of nowhere, focusing on the storm-lashed road ahead, but a panel light announced an engine malfunction and a reduction to half-power. Nothing changed in the way X5 drove, and the light went off in a few moments.