The vague feedback through the steering and suspension made us feel even more isolated from the driving experience, but somehow we think that's the point of driving a vehicle this large. The leather-trimmed seats were quite comfortable for the seven-plus hour trip, but the high seating position had us feeling like we were sitting on top of a vehicle rather than inside of one. Speeding down Interstate 5, cruise control holding the SUV at a steady 75 mph, the GL's leather appointed cabin isolated its passenger from road and wind noise. The GL isn't an athletic vehicle in any mode and the Default mode was more than sufficient for most situations, causing us to question the utility of the $750 option. The three modes felt noticeably different, with Sport mode transmitting a good deal of expansion joint harshness into the seat bottom and Comfort mode feeling floaty and vague. Our G元20 was equipped with the optional Adaptive Damping System, which adds a Sport mode and a Comfort mode to the suspension's Default setting. The GL's default suspension mode is good enough for most situations. Once the G元20's BlueTEC diesel settles into its groove, such as during highway cruising, power remains strong, allowing the GL to pass/merge with ease and coast along at freeway speeds while taking advantage of the transmission's tall seventh gear to keep the revs low.
Really putting your foot into the accelerator and waiting for the turbodiesel to build steam eventually results in that torquey diesel thrust that we're used to, but the acceleration is uneven and slightly unpredictable. Whatever the cause, the G元20 feels sluggish off of the line.
Perhaps this is because of the GL's immense weight perhaps it's the turbo lagging or maybe Mercedes has tuned some of the throttle response down to create more refined and fuel efficient acceleration. On the road, the 398 pound-feet of torque doesn't translate into neck-snapping acceleration. Greenies will be happy to know that the BlueTEC diesel is also approved for use with B5 biodiesel. Keeping the diesel's emissions clean is an AdBlue injection system that scrubs up to 80 percent of NOx from the exhaust gases. The engine sends its power through a seven-speed adaptive automatic transmission to Mercedes-Benz's 4MATIC permanent all-wheel drive system. The powerplant in question is a 3.0-L turbodiesel V-6 that outputs 210 horsepower and a beefy 398 pound-feet of torque. While this seven seated behemoth was probably not the best vehicle to transport one journalist across the state of California, we figured this long trip down Interstate 5 would be a good opportunity to see how close the fuel-efficient diesel powerplant could get to its EPA estimated mileage. We were recently given the opportunity to take the 2009 Mercedes-Benz G元20 BlueTEC on a long-distance road trip from San Francisco to Los Angeles and back. We may have saved a few mpg on our road trip, but we didn't do any favors for the insect life along I-5.