Mercedes-Benz GL320 BlueTEC beats EPA mpg

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.

(Credit: Corinne Schulze/CNET)

We were recently given the opportunity to take the 2009 Mercedes-Benz GL320 BlueTEC on a long-distance road trip from San Francisco to Los Angeles and back. 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.

The powerplant in question is a 3.0-L turbodiesel V-6 that outputs 210 horsepower and a beefy 398 pound-feet of torque. The engine sends its power through a seven-speed adaptive automatic transmission to Mercedes-Benz's 4MATIC permanent all-wheel drive system. Keeping the diesel's emissions clean is an AdBlue injection system that scrubs up to 80 percent of NOx from the exhaust gases. Greenies will be happy to know that the BlueTEC diesel is also approved for use with B5 biodiesel.