Aside from the gasoline options, the 2018 GMC Terrain is also available with a 1.6-liter turbodiesel unit, which may end up overshadowing the more powerful 1.5-liter petrol.
At least according to the guys from TheFastLaneCar, who tested the two Terrain versions side by side and found the 1.6-liter diesel to be quiet, reasonably punchy, obviously more fuel efficient and even better-sounding than the 1.5 petrol.
The diesel unit is good for 137 HP and 240 lb-ft (325 Nm) of torque, while the 1.5 turbo petrol puts down 170 HP and 203 lb-ft (275 Nm) of torque.
On paper, the Terrain diesel should return around 28 mpg (8.4l/100km) in the city, and 38 highway mpg (6.2l/100km), which is certainly advantageous compared to the 1.5-liter petrol model, which will only do 24 mpg (9.8l/100km) in the city and 28 mpg (8.4l/100km) on the highway.
In the end, it comes down to personal preference and purchasing price. Also worth noting is the fact that maintenance costs are about the same, so with that in mind, which one would you rather own?