What Makes Diesel Engines Ideal For Long-Haul Trucking? (And Are There Any Gas-Powered Semis?)

While the list of car brands that still use diesel engines in 2025 is increasingly small, diesel still dominates when it comes to heavy-duty trucks. There are a number of reasons why diesels are the obvious choice for long hauls, with one key reason being that diesel engines make more torque than an equivalent gasoline engine would. The more torque an engine produces, the heavier loads it can pull, which makes diesels naturally suited to the heaviest-duty uses. Diesel engines also tend to be less maintenance-intensive than gasoline engines and feature a simpler construction, which reduces the number of components that can go wrong.

Another benefit of using diesel engines for semi-trucks is that they run at a lower rpm on average than gasoline engines, which cuts down the level of wear on key engine components. This results in diesel engines having a longer lifespan, which makes them cost-effective for truckers who need to drive hundreds of thousands of miles in their vehicles. If that wasn't enough, diesel engines are also more efficient than their gasoline counterparts, which not only reduces the amount of emissions a truck produces but also means that owners save money on fuel. A more efficient truck can also cover more miles between refueling stops. But diesel hasn't always been the only choice for semi-trucks.

With diesel truck engines holding so many advantages over gasoline engines, it's easy to see why no semi-truck manufacturers offer gasoline engines for their vehicles today. Diesel has been the fuel of choice for truckers for many decades, although GM did offer a gasoline engine for its heavy-duty trucks back in the '60s. Between 1961 and 1965, the company produced a 702-CI V12 truck engine, pictured above, that achieved just three mpg. The V12 was primarily fitted to semi trucks, but could also be found in some fire trucks of the era. Some farmers even used the V12 to power irrigation systems.

It's extremely unlikely that any semi truck maker will ever offer a gasoline truck engine again, but truckers who aren't sold on diesel power aren't completely out of options. Truck makers such as Peterbilt and Freightliner offer semi trucks powered by natural gas, while electric trucks are a zero-emission alternative to diesel for short-haul uses. Traditional semi-truck manufacturer Kenworth now has a Tesla semi rival, although EV semi-trucks' shorter range and the limited charging infrastructure available mean that diesel trucks will likely continue to rule the roost for long-haul applications for the foreseeable future.