So you’re interested in buying a pickup truck to haul a truck camper, but aren’t sure whether to get one with a diesel or a gas engine. You’re not alone. Many have struggled with or are currently struggling with the same decision. There are pros and cons associated with each. The key is determining exactly how and where the truck will be used, how long it will be owned, your budget, and what kind of payload rating you need. Unfortunately, some truck camper owners have already made the wrong choice and are having to live with their mistake. With a new pickup costing anywhere between $35,000 and $90,000, it’s an expensive error to make. It’s best to make the right choice first before signing the dotted line. That’s the purpose of this article. Using nine decision points, this article takes a look at the strengths and weaknesses of each engine type in order to help you, the consumer, make a better and more informed decision.
1. Acquisition Cost
Diesel engines are significantly more expensive than gas engines. For three-quarter-ton and one-ton trucks the cost for a diesel is approximately $8,000, while the gas engine falls within the $1,000 to $2,000 price range. Why is the diesel engine more expensive? Primarily, because it needs to be built more robustly with thicker cylinder walls and stronger and more durable cylinder heads, valves, crankshafts, and pistons. These beefier components are needed to withstand the extreme stresses and high heat found in diesel engines. Not only that, but diesel pickups require a stronger and more expensive transmission to handle all that extra torque and specialized turbochargers and emission control equipment that add additional cost. Yes, it’s true that diesels provide better fuel economy to offset that additional cost, but it may take 160,000 miles before the fuel cost benefit makes up for the initial purchase price.
2. Fuel Economy
Gas engines are benefiting from several new technologies such as direct-injectors, cylinder deactivation, variable valve timing, and turbocharging, but diesel-powered pickups still provide better fuel economy with an advantage between 30 to 35 percent. For example, a gasoline-powered one-ton truck hauling a 3,000 pound truck camper at 60 mph, will typically get 9 to 10 mpg, while a similar size truck with a diesel engine doing the same speed will easily achieve 14 mpg. Of course, those mileage figures will vary, depending on the terrain (like driving in the mountains), but the mileage gap between the two won’t. A final point worth considering is that Ford, Ram, and Chevy all offer an additional diesel fuel tank as an option, which can significantly increase the operating range of a diesel pickup truck even more.
3. Fuel Costs per Gallon
According to the U.S. Energy Information Administration, the average price for a gallon of gas in Nov. 2016 was $2.18, while an average gallon of diesel was $2.44. Historically, diesel fuel has averaged about 14 cents more per gallon than regular unleaded gasoline. This varies, of course, as market prices fluctuate. Sometimes a gallon of diesel can be purchased for less than a gallon of regular gasoline, but since 2003, this has been the exception rather than the rule. Another benefit with regard to gasoline is that every filling station offers it, unlike diesel, which can be hit or miss. Indeed, sometimes it can be difficult locating a filling station that carries it. This can result in wasted time (and fuel) trying to find one. This is why diesel owners should never let their tank get lower than half full while on an outing in unfamiliar territory.
4. Maintenance and Repair
It’s a myth that diesel engine maintenance is more costly than gasoline engines. That may have been so back in the ’80s and ’90s, but not anymore. Sure, an oil change for a diesel can get pretty pricey (the typical diesel requires 12 quarts of oil), but improvements in diesel particulate technology have extended the oil change interval for the Cummins 6.7L engine from every 7,000 miles to every 15,000 miles (some warranties require shorter intervals between oil changes, so this should be kept in mind before scheduling maintenance). It’s true that the water separator and fuel filters in a diesel will require replacement more often, and that you’ll need to periodically drain the engine’s water-separation bins, but this is offset by the fact that diesels don’t require things like spark plugs and ignition tune-ups. Overall, the reliability and longevity of the diesel make the investment in money and time worth it. It fact, the reliability of the diesel is a major asset. Catastrophic hard-part failures are pretty rare during the life of a typical diesel.
Government regulations on emissions have made things tough on automakers, this is especially true for vehicles equipped with diesels. In 2010, the EPA imposed strict diesel emission regulations, requiring the use of an automotive grade of urea or diesel exhaust fluid (DEF) to “scrub” nitrogen oxide (NOx) from the Selective Catalytic Reduction (SCR) system and exhaust. While this fluid reduces NOx emissions by as much as 90 percent—and near-zero when used in combination with diesel particular filter technology—all this extra emissions equipment comes at a major cost. First, having to fill your 5.5-gallon DEF tank every 4,000 miles is an inconvenience and an added expense (a 2.5-gallon jug of DEF costs about $14). Second, DEF leaves harmful deposits in your SCR system that build up over time eventually requiring expensive repairs to DEF pumps, DEF injectors, and NOx sensors. Three, the “regen mode,” which is used to periodically clean the diesel particulate filters by over-fueling for a short period of time, has a negative impact on fuel economy and power.
The typical diesel engine weighs about 800 pounds more than a gasoline engine. This results in a corresponding reduction in a truck’s payload capacity. Now 800 pounds may not sound like much, but when it comes to payload, every pound matters. Because of this, consumers interested in getting a diesel and hauling a truck camper should set their sights on a one-ton pickup truck, like a Chevy 3500 or a Ford F-350, rather than a half-ton or three-quarter-ton. The penalty in payload for having a diesel is simply too large for lower rated pickup trucks. This is especially true if you’re interested in hauling a moderately equipped hard-side truck camper. Fully loaded, that truck camper will weigh approximately 3,000 pounds. The only three-quarter-ton pickups with payloads that high are gasoline-powered.
7. Horsepower and Torque
Torque is where the diesel engine really shines. For example, the Cummins 6.7L turbo diesel can deliver a whopping 900 foot pounds of torque, while the 6.4L V8 HEMI is limited to just 429 foot pounds. It’s true that the gasoline engine delivers more peak horsepower—410 horsepower for the 6.4 L HEMI compared to 385 horsepower for the Cummins 6.7L—but the gap between the two engine types is pretty insignificant and closing fast. There’s no doubt about it, if you plan on hauling a truck camper in mountainous terrain or plan on towing a large boat, jeep, or utility trailer, then you’ll want to get a diesel. There’s simply no comparison between the two, especially when climbing difficult 6 percent mountain grades.
8. Noise, Vibration, and Harshness (NVH)
Advantage: Slight edge to Gasoline
For years diesels rightfully suffered from a bad rap for being excessively noisy, smoky, and smelly. Indeed, in the ’80s and ’90s you couldn’t hold a conversation next to a teeth-rattling diesel nor stand anywhere near the exhaust without feeling light-headed and gasping for air. Clouds of smoke during startup were pretty commonplace, too. Fortunately, things are much different now. Advances in fuel injection, emission, and common-rail technologies have brought the two engines types to a near equal footing. Vibration and harshness standards in diesels have been improved, too, enough that diesel engines can be found not only in commercial vehicles, but also in many luxury cars. In fact, when it comes to NVH, the two engine types are almost indistinguishable today, with the characteristic diesel “rattle” being the most obvious difference.
9. Engine Longevity
It’s no secret that diesel engines last longer than gasoline engines—600,000 miles for a diesel is pretty common. Why is this? Because, as was explained earlier, diesels require a beefier engine block and stronger more durable cylinder heads, valves, crankshaft, and pistons. These sturdier parts are necessary to dissipate the higher engine temperatures and higher compression ratios found inside of them. Not only that, but the exhaust produced by diesel engines is less corrosive. All of this results in a truck and engine that will last longer and have a better resale value than their gasoline-powered counterparts. If your plans include keeping your pickup truck for only a couple of years then I would skip the diesel and buy a gasser. On the other hand, if your plans include putting a lot of miles on your truck and keeping it for many years, then a diesel will serve you better and save you more money in the long run.