Which engine – gasoline or diesel – is best for light-duty vehicles? The age-old answer is, of course, it depends. It depends on annual mileage, fuel economy, purchase price, expected lifespan, fuel costs, maintenance and more; a whole assortment of considerations specific to the fleet.
Those considerations still drive the fleet’s decision tree, but recent advancements in the engines, oils, fuels, maintenance support and even onboard performance data have given fleet buyers more means to find the best power choice.
Take lifespan, for example. Advancements in equipment durability and manufacturing processes combined with higher-quality fuel and oil are pushing out the average lifespans of gasoline engines, said George Survant, senior director of fleet relations for NTEA – The Association for the Work Truck Industry (www.ntea.com) and a former utility fleet executive.
“Ten, even five years ago, fleets would turn in their gasoline-powered truck at about seven years and 70,000 miles,” Survant said. “Now, I wouldn’t consider turning it in under 150,000 miles.”
Fuel economy is another example. The newer non-hybrid gasoline engines with single or dual turbos, less weight and multispeed (6-, 8- and 10-speed) transmissions have narrowed the traditional fuel economy gap with diesels, with some spark-ignition units getting ratings of 18 mpg in the city and 22 on the highway. Power ratings are up, too. Ford’s 2017 3.5-liter V-6 EcoBoost rates a beefy 470 pound-feet of torque.