Cadillac XT6 vs GMC Terrain: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the GMC Terrain burns about $2,200 of fuel annually against $2,950 for the Cadillac XT6. That $750 yearly gap compounds to roughly $3,750 over five years and $6,000 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City and highway economy: the GMC Terrain leads in both cycles — 28 mpg city and 39 mpg highway against 21 and 27 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Cadillac XT6 is recorded with 1 distinct engine configuration (SIDI), the GMC Terrain with 3 (SIDI, 1.6, SIDI; FFV). Across 22 recorded Cadillac XT6 configurations and 47 for the GMC Terrain, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the Cadillac XT6 is offered with Front-Wheel Drive, All-Wheel Drive, the GMC Terrain with All-Wheel Drive, Front-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Small Sport Utility Vehicle 2WD and Small Sport Utility Vehicle 2WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the GMC Terrain emits 316 g/mile of CO2 versus 386 g/mile for the Cadillac XT6. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.