Are Diesel Trucks Worth the Extra Cost?
Updated: 7 hours ago
Gas vs. Diesel for Towing an RV:
If you tow a travel trailer or fifth wheel, you’re probably already familiar with the debate that’s been raging across the internet for decades: should you get a gas or diesel truck for towing your RV?
There are lots of opinions across lots of forums, and everyone has their own take. We’ve owned and towed with both gas and diesel trucks, and we know what we like best for functionality and peace of mind. But this week, we decided to dig into the data: in the great debate of gas vs. diesel, is there an objective best choice? And are diesel trucks worth the added investment?
Read on for what we found, from upfront costs to the total cost of ownership (TCO) to resale value. We’ll break our overall findings down by key considerations and then share some of our data sources so those who are interested can take a look.
Upfront costs
Gas trucks are typically less expensive to purchase upfront than diesel. If you’re looking to buy a diesel, you can expect to spend about $8,000 to $11,000 more than you’d spend on the gas version of the same vehicle—and maybe even more, depending on how hot the diesel market is when you’re buying.
Diesels cost more than their gas counterparts due to heavier construction, more towing capacity and torque, and a more complex emissions reduction system. (When it comes to maintenance, this system is a negative—but more on that below.) That said, they also tend to hold their value better at resale due to a longer expected “lifespan” than gas. We’ve heard engine buffs say that a diesel engine has just gotten broken in at 100,000 miles, while a gas truck is likely well past its prime.
Fuel Economy
Diesel engines offer better fuel economy than gas due to the higher energy density of diesel fuel, which means they don’t need as much in the tank to generate the same power as gas engines. This difference can be significant—according to the U.S. Department of Energy, diesel-powered vehicles get 20% to 30% more mileage per gallon on average than gas engines.
That said, the cost per gallon of gasoline has been consistently cheaper than diesel for several years now. Modern diesels also require the addition of diesel exhaust fluid (DEF), an added ingredient that costs extra money, so the difference is probably a wash.
For us, the biggest advantage to diesel fuel economy when towing is that we don’t need as many fuel stops to get from point A to B, so diesel has been a positive when long-distance towing.
Get Fleet Rates When Buying Diesel
“Hey, fuel is 10 cents cheaper across the street, let’s go over there?!?” said Marc never! We pick gas stations based safety first, reputation of the brand second, and ease of getting in and out third.
Yet, with diesel fuel cards, we’re not talking about cents, we’re talking dollars and for RVers, it can add up to hundreds of dollars in savings in no time at all.
We love visiting truck stops for the following reasons:
Safety! Period. I’ll gladly pay more without risking damage to the RV
Significant fuel savings through the TSD Fuel Program
The pump doesn’t shut off at $100
High-flow pumps save time
Its easier to clean the windshield with long poles and clean fluid
Great customer service with clean facilities
Do I need to mention the CAT scale??
If you own a diesel truck or RV, there are significant savings to be had through a fuel savings card. You can get fuel from most truck stops at fleet prices. We’ve been using the TSD Fuel card for a couple years now and we’ve seen big savings.
If savings is your number priority, just download the app to find out where the biggest savings are.
Some people have written in saying that the fuel card stops just hike up their prices to offset the savings. Not exactly. Truckers pay an over-the-road fuel tax. At most truck stops, you’ll notice fuel on the “car side” is cheaper than the truck lanes.
Keep in mind, one incident or damage to your RV trying to negotiate tight quarters will cost you your fuel savings for the next year! Plus, in most cases, the savings of fuel card offsets the higher price.
Maintenance
Gas trucks have the advantage here, despite the need to change out spark plugs at regular intervals. While diesels don’t have spark plugs, they do tend to have higher long-term maintenance costs than gas due to their complex emissions systems.
The exhaust gas recirculation (EGR) system that reduces harmful emissions from diesel engines has a definite downside. The parts tend to clog up and need replacement over time, and the components of these systems are expensive.
Diesels also require specialized knowledge to service, so it can be harder to find a mechanic who’s qualified to help if your diesel engine needs repair.
One bright spot for diesel is oil changes. In general, gas trucks require oil changes every 5,000 miles, while diesel can last closer to 7,000 miles between oil changes (or even longer, depending on the manufacturer). That said, diesels also hold more oil, so each change is more expensive. Due to the cost of diesel oil changes, we switch to synthetic oil on the first oil change promptly at 5,000 miles (as there may be more metal contaminants during the break-in process) and then change at a much longer (on somewhat controversial) frequency. We send an oil sample to Blackstone Laboratories to get a complete assessment of our oil and change based on their recommendation. The testing is about $35 and provides peace of mind of the condition of our oil.
Towing and hauling
Diesel trucks have higher torque and an integrated exhaust brake, plus better fuel economy under heavy loads. All of these qualities have made them longtime favorites for RVers, especially those who own heavy rigs or travel long distances.
Gas trucks often have higher towing capacity due to their payload, but they have less torque for towing. The lighter weight in comparison to the trailer also makes them more susceptible to forces like wind (or passing semis) on the road. We’ve noticed a big difference when driving on windy days with a diesel vs. a gas truck.
Engine lifespan
Diesels are known for their durability, often blowing past 200,000 miles. As we mentioned above, diesel enthusiasts often consider the first 100,000 miles to be the break-in period, with the engine’s best days just beginning. Semis are expected to operate for half a million miles or more before they’re decommissioned for commercial use.
This longevity is thanks to stronger engine blocks and tougher internal parts designed to withstand high compression ratios. Diesel fuel is also less corrosive than gas, which supports the lifespan of the diesel exhaust system.
Because of their durability over time, diesel trucks typically have a higher resale value than gas, especially at high mileage.
That said, gas trucks have come a long way, and modern trucks can tow heavy loads with impressive torque. Gas trucks often have a higher payload than diesel, because their engine components are lighter and take up less of the overall GVWR. If you’re doing extensive towing and heavy hauling, a gas machine will wear out faster than diesel, but gas trucks can last a long time under more balanced usage.
Depreciation cost
Why the question mark on this one? We expected diesel to be a clear winner here, so we were a bit surprised too—but we’ll get there.
For now, if you’re looking at flat resale value, diesel trucks have higher resale values than their gas-powered counterparts. This has been even more apparent since 2020, when the diesel market really started to heat up. Some studies, like a University of Michigan study done back in 2012-2013, found something like a 35% spread in value between gas and diesel trucks at auction.
That said, the gas market is rising again, partly because of the simpler maintenance required. Diesels are also more expensive to purchase upfront, and as we’ll see, the higher resale value may never offset that added investment when you factor in the higher maintenance costs.
Gas vs. diesel overview
Before we geek out on some of the data, let’s run through what we know so far with a classic list of pros and cons.
Diesel Pros:
Fuel economy
Longevity, with an expected lifespan well over 200,000 miles
Longer maintenance intervals
Higher resale value
More torque for better towing
Diesel Cons:
Specialized maintenance, including fuel filter service and diesel particulate filter (DPF) cleaning
Higher maintenance costs
More expensive upfront
Gas Pros:
Lower upfront cost
Simpler maintenance
Lower parts costs
Simpler emissions system
Can have a higher payload
Gas Cons:
Shorter oil change intervals
Lower resale value
Fewer heavy-duty parts to withstand hard use
Less efficient gas mileage
Total cost of ownership: which is better?
When we dug into the data, this was one of the more surprising data points we found. If you’re looking at flat depreciation, diesels hold their value better than gas. So why is the gas vs. diesel debate still raging?
For a long time, diesel trucks were a clear winner in total cost of ownership. Look no further than that University of Michigan study, which showed that diesel trucks saved their owners an average of $2,000 to $7,000 over 3-5 years of ownership.
However, the higher cost of diesel fuel and long-term maintenance costs have made these figures more murky. A 2018 Vincentric U.S. Diesel Analysis (the most recent “official” study we could find) showed that while diesel vans are more cost-effective than gas, none of the 300+ diesel trucks they analyzed had a better TCO than the gas versions. In fact, the average cost of ownership over the lifetime of a diesel was about $2,000 more than the gas equivalent.
While the specifics will vary, you can do the math for yourself using the very cool calculator created by James from The Fit RV. If you plug in the expected cost of diesel vs. gas ownership over time, it turns out that the higher upfront cost of diesel may never pay for itself, despite the higher resale value. If it does, it could take somewhere in the neighborhood of 400,000 miles to get there.
How to decide which truck is right for you
In the end, we think it all comes down to what you plan to use your truck for and how often you plan to replace your vehicle. If you’re looking for “the last truck you’ll ever own” (famous last words), you’ll probably want to buy a diesel, which has a longer expected lifetime. If you’re doing a lot of heavy-duty towing over time, diesel is probably still the best fit.
On the other hand, if you’re towing lighter weight less frequently, or if you want something to take you off-road and around town, gas is probably a better value for you. (And, according to the math, it might just be a better value for most.) Gas trucks have certainly come a long way in the last ten years, making them a more competitive option for towing than ever.
For us, the choice comes down to performance. We like the peace of mind that comes from having heavy-duty parts and an exhaust brake when going down steep grades. Airstreams are heavy, and while we could tow ours with a gas truck, we like the performance of a diesel. And we probably couldn’t have gone over mountains towing our toy hauler with a gas truck—at least, not quickly.
As with most things in the world of RV travel, we think the choice between gas vs. diesel comes down to your budget, travel style, towing equipment, and appetite for DIY projects or unexpected repairs.
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