Gas or diesel pickup? It all depends on how you plan to use it

There are lots of options to consider when you’re buying a pickup, but one of the biggest decisions is whether to go for gasoline or diesel. There are pros and cons to both, but all of them revolve around what the truck costs to buy and run.

Diesel engines offer better fuel efficiency and longevity, but they come with extra expenses. Diesel is available in the heavy duty versions of Chevrolet Silverado, Ford F-series, GMC Sierra, and Ram. It’s also a choice in the Nissan Titan XD, a truck the company says slips in between a half- and three-quarter-ton truck.

A diesel is now available in the Ford F-150, and will be coming to half-ton models from GM (for the first time) and Ram (returning on the new 2019 model). Among midsize trucks, only the Chevrolet Colorado/GMC Canyon offer a small diesel engine.

Diesel is pricier when you’re buying a new truck. On a mid-size or half-ton truck it adds more than $5,000 over a gasoline engine, while on a heavy duty, it can be close to $10,000 more. Diesels are more expensive to build because their parts are more robust, and they require extra systems and filters for emissions.

Diesels are also more expensive to maintain. Their oil changes cost more, and you have to add diesel exhaust fluid, or DEF. This is a urea-based liquid that’s automatically squirted into the exhaust system — not the engine — to offset oxides of nitrogen (NOx), a smog-producing pollutant. The DEF tank usually needs filling around the same time you’ll need an oil change. If you do start to run out while driving, the truck will give you numerous warnings well ahead of it being completely empty. But if you ignore them and run the tank dry, a governor will limit the engine’s speed until the DEF tank is refilled.

Diesels also use particulate filters to trap soot. Sensors determine when these are full and divert some fuel to a catalyst, raising the temperature to burn the soot off. While they last a long time on a properly maintained vehicle — typically into the hundreds of thousands of kilometres — these filters may eventually need professional cleaning or even replacement and fill up faster if you primarily do short trips.

Diesels are much happier when taken on longer trips. If your driving is exclusively short trips around the city, go for gasoline.

Diesel engines are inherently more fuel efficient, although improvements in gasoline power plants are closing the gap. For a 2019 Chevrolet Colorado, for example, the diesel is rated at 10.5 L/100 km, versus 12.2 L/100 km for the gasoline V-6. Just as with a hybrid versus a conventional car, it can take many accumulated kilometres before the fuel saved outweighs the engine’s extra cost. Volatile prices on either fuel will also speed up or slow down your rate of return.

Diesels typically last longer than gas engines and generally command higher resale value.

Diesels take the towing crown in the beefy, over-engineered heavy duty segment, but be careful if you’re going for maximum pulling power in a half-ton. These engines are heavy, and that extra weight can cut into capability. In an F-150, for example, the 3.0-L diesel has a maximum towing capacity of 11,500 lbs. — but the 3.5-L EcoBoost gas engine goes as high as 13,200.

Turbocharged gasoline engines can provide impressive power, but when they’re worked hard, that turbo pushes in more air, and subsequently, you use more fuel. If you tow frequently, a naturally aspirated engine — even a larger-displacement one — could end up costing less in fuel in the long run.

Overall, both gas and diesel have their hits and misses, so it’s really about what you need the truck to do. Look objectively at how you use your truck, how much you drive it, and how long you’re going to keep it.

Making the right choice — whether diesel or gas — could save you a lot of money.

Driving.ca