Business owners shopping for a work truck or delivery van may learn they can choose a diesel engine instead of one that runs on gasoline. But does the higher purchase price of a diesel make good business sense over the entire length of ownership? Here are some points to consider before making your purchase.
The Diesel Difference
The main differences between diesel and gasoline engines are the types of fuel they use and how they burn it. A diesel engine uses high compression to ignite the fuel-air mixture in its cylinders, while a gasoline engine uses spark plugs as its ignition source. The higher compression forces of diesels, however, require heavy-duty parts, which make them heavier and more expensive than their gasoline counterparts.
Depending on the manufacturer and model of a truck or van, the diesel option can cost as much as $7,000 more than its gasoline-powered equivalent. If you hope to earn back the price of the diesel option with better fuel economy, you may be driving the vehicle for a very long time. And diesel fuel, which historically has been cheaper than gas, today is often the same price--or higher.
Winner: Split decision
How you will use your vehicle should be a major factor in determining what you buy. Will you use it around town, where quick starts are important? Do you rarely tow a trailer or haul a load? If so, then a gas engine may be your best choice.
However, if you frequently tow trailers or haul loads, consider a diesel. Because of its high-compression operation, a diesel makes its torque and power at low speeds, making it perfect for pulling heavy loads up steep grades.
Diesel fuel is a product of refining gasoline, and since the slower economy has caused a reduction in gasoline refining, there is less diesel fuel. Demand for diesel fuel, however, is driven by commercial usage which makes it a less discretionary expense. As a result, its price hasn't fallen as steeply.
According to the Energy Information Administration, in 2009 the annual average regular-grade gasoline retail price is expected to be $2.36 per gallon. Higher crude oil prices in 2010 are expected to increase the average price to $2.69 per gallon. Annual average diesel fuel retail prices are expected to be $2.46 and $2.79 per gallon in 2009 and 2010, respectively.
Diesel fuel has more energy per gallon than gasoline, making diesel engines more efficient per gallon of fuel burned. Additionally, diesel engines use a more efficient fuel delivery system than gasoline engines. Although the EPA does not require manufacturers to publish fuel economy information for large trucks and vans, diesels typically deliver 20 to 30 percent better fuel economy than gasoline engines.
One reason people avoid diesel-powered vehicles is the lack of fuel availability. Only about 2 percent of this country's vehicles are diesel powered, so fewer places sell diesel fuel. Manufacturers would build more diesels if consumers would buy them. Consumers might consider diesels if there were more places to refuel. Fuel companies, in turn, might produce more diesel if there were greater demand.
Today's gas engines have significant advantages over diesels, due to their extended service intervals on spark plugs, engine oil, and antifreeze. Regular service for a diesel costs more for several reasons. Diesels require a larger oil capacity, and they have fuel filters and water separators that need servicing more frequently.
Long-Term Maintenance and Durability
A diesel engine's outstanding durability can be attributed to its heavy-duty parts and the lubrication properties of diesel fuel. Generally speaking, the average gas engine can go for 125,000 miles before needing major repairs. It's not uncommon for a diesel to go more than 300,000 miles before requiring serious mechanical attention.
As mentioned earlier, a diesel relies on high compression to ignite its fuel. When outside temperatures are below freezing, the air is too cold to ignite. To address this problem, most modern diesels offer a heating element designed to keep the engine block warm when the truck is parked. Having to plug in and unplug your vehicle can be a hassle, though, and there's always the chance that there might not be a place to plug in once you reach your destination.
Ultimately the decision of whether to choose a diesel- or a gas-powered vehicle depends on how you will use it. If you plan on driving it around town like a car, rarely towing a trailer or hauling heavy loads and won't keep it past 100,000 miles, a gas-powered vehicle best meets your needs. They're not as expensive, fuel is readily available, and they can operate in sub-freezing temperatures.
However, if you need a vehicle that can tow or haul heavy loads, want better fuel economy, and plan on driving it for many years, then consider a diesel. Although the price premium over a gasoline engine is significant, if you need the qualities of a diesel, a compelling case can be made for its purchase. Sometimes, making a good business decision means considering more than just the bottom line.