Long-term Update: 2007 Mercedes-Benz GL450

On an inbound commute to work, Truck Trend art director Thomas Voehringer noticed the GL's tire-pressure-warning light had come on. "Once in the garage, I put a gauge to each tire and found the driver-side front was down 5 psi. I took it over to Just Tires, and they found a nail in the tire close to the sidewall." Patched and ready for the road, the set of original-equipment Continental 4x4 Contact tires wouldn't be around for long-with just over 22,000 miles, the tread had become even with the wear bars, signaling a replacement was needed.

Mercedes uses four different OE tires for the GL, one being the new Michelin Latitude Tour HP, which we opted to try in favor of the 4x4 Contacts. Cost for the Latitudes, size 265/60R18, from the Tire Rack was $772 ($192 per), with installation running $115.66. Total cost set us back $887.66.

On a drive home from the office, Truck Trend editor Mark Williams noticed the GL, with a little over 24,000 miles on its odometer, was emitting a noisy driveline whine that made it almost impossible to cruise with the windows down. Online editor Michael Floyd agreed, querying, "When did we get the GL450 Kompressor? It almost sounds like someone snuck under the hood and bolted on an IHI supercharger." Despite belting out its own karaoke imitation of Axl Rose when the tach needle went north of 2500 rpm, the GL managed to deliver trouble-free performance until we could get it in to the local dealer just shy of 26,000.

At the Benz dealer in Beverly Hills, the GL's whine was diagnosed and the second scheduled tuneup performed. For $571.04, the service crew dumped in fresh Mobil 1 synthetic oil, rotated the tires, and inspected the brakes. The rear brake pads, at 3 mm, were deemed worn out, so those were replaced, along with a rear brake sensor, for another $357.42.

And that whine? While various editors speculate it might be a lube-deprived driveshaft or a tranny output shaft in need of a squirt, it turned out to be an engine guide pulley gone bad. According to the dealer, the faulty idler pulley is a common problem in GLs; luckily, it wasn't a major issue and was covered under warranty.

With the GL good to go, Williams chauffeured his daughter's entire Los Angeles Futbol Club Girls U-15 soccer team to an MLS game at the Home Depot Center in Carson, California. Williams notes, "The girls liked how the GL went up and down with the suspension settings and they appreciated the satellite radio, but if I hear one more thing about Delilah or how big girls don't cry, I'm going to puke." Ah, the joys of fatherhood. Although instructed to stay invisible, Williams was at least able to "hear seven teenage girls debate the relative merits of Orlando Bloom's dreamy smile and Harry Potter's nerdy charm." We're going to miss the GL, but we know the GL will miss us more.