Let's get the bad news out of the way first. The 3.0-liter in-line six in our Four Seasons BMW 330i suffered a major mechanical failure.
This isn't the first time one of our Four Seasons BMWs has been plagued by problems under the hood. Our 1994 540i needed a new V-8 after only 30,000 miles, when it lost compression in two cylinders. Our 2001 M3 went through two throttle-valve actuators and a throttle-position sensor and suffered from valve clatter. Finally, our 2003 745Li visited the service bay for the first time at only 1700 miles, when the lift mechanism of its Valvetronic variable-valve-timing system had to be adjusted because of an emissions-related engine error code.
The first indication of a problem with our 2006 330i was valve ticking at cold idle. Before long, there was constant valve noise throughout the rev range at all operating temperatures. BMW of Ann Arbor diagnosed worn camshafts, lifters, and rocker arms caused by a lubrication failure in the cylinder head. As a result, our car was off the road for five weeks, awaiting further diagnosis and parts from Germany. Luckily, the car was still under warranty, but we would have been hyperventilating over a $4300 repair if that weren't the case. We have long admired BMW engines, but we're starting to wonder whether or not some of their cutting-edge technology is truly ready for the production line.
Other than the five-week period when the BMW was in the shop, the 330i was quite reliable. But that didn't stop us from making a few negative remarks in the logbook. The most common complaint was about the harsh ride quality, which is no doubt due to a combination of standard run-flat tires, the optional sport suspension, and Michigan road surfaces that feature a topography similar to that of the moon. "The suspension noise and choppy ride began to get very old after the four-hundredth or so freeway mile," wrote assistant editor Erik Johnson. Our hard-core enthusiasts pined for a limited-slip differential, a feature BMW seems to reserve only for its M-badged cars, leaving its other rear-wheel-drive models to rely solely on stability control to improve traction. At least BMW offers an intermediate mode for the stability control system, which allows more wheel spin and greater slip angles before the electronics intervene.
Another point of contention is BMW's redesign of simple controls that worked perfectly well in the first place. The most egregious example is the key-start interface, noted by copy editor Rusty Blackwell: "I don't mind a push-button start, but why should I have to insert the key fob into a slot first and then push a separate start button?" Both the indicator and wiper stalks frustrated more than a few drivers. "Why fix what isn't broken?" asked copy editor Adrienne Newell. "The stalk resets to a neutral position after each wiper speed selection, and the steering wheel blocks the small light indicating when the system is in automatic mode."
Some drivers also thought the clutch was overly springy and the long-throw gearbox was slightly notchy, but the BMW nuts at the magazine disagreed. These same Bavarian Motor Works devotees, however, disdained the lack of oil and water temperature gauges and the waste of precious instrument-panel space for a near-worthless analog instant fuel mileage display. Someone in Munich clearly shares their opinion, because the 2007 335i switched to an oil-temperature gauge and properly buries the instant fuel economy display in the trip computer.