Diesel vs Gas Trucks: Pros and Cons (2026 Update)

The diesel-versus-petrol argument in pickups has been running long enough that both sides have their catechism. Diesel people talk about torque, towing and engines that run to half a million miles. Petrol people talk about purchase price, cold starts and the cost of an emissions system failure. Both are describing something real, and neither is describing a number.

So here are the numbers. The EPA publishes tested fuel economy and an estimated annual fuel cost for every light-duty vehicle it certifies, calculated at 15,000 miles a year, and it publishes them separately for each engine offered in a model. That makes a like-for-like comparison possible within a single truck rather than across brands — and what it shows is more interesting than either camp usually admits.

What the EPA figures actually say

The 2018 Ford F-150 is the clearest case available, because it was offered with five different powertrains including a 3.0-litre turbo diesel, all tested by the same programme in the same year.

Read the first two rows together, because they contain the whole argument. The diesel is the most efficient engine in the range by a clear margin — 25 combined against 22 for the best petrol option, and 30 on the highway against 26. And its estimated annual fuel cost is $3,200 against $2,800. The diesel does more miles per gallon and still costs $400 a year more to run.

That is not a contradiction. It is what happens when the more efficient fuel is also the more expensive one per gallon. A 14 percent efficiency advantage does not survive a larger price-per-gallon disadvantage, and the EPA’s cost model — which uses national average fuel prices — captures that where the MPG figure alone does not.

Compare the diesel to the 5.0-litre V8 and the picture is even starker: the diesel is six MPG better on the combined cycle, and saves you $50 a year. Fifty dollars.

The Ram 1500 tells the same story

The 2018 Ram 1500 was also offered with a 3.0-litre turbo diesel alongside petrol engines, and the pattern repeats.

Again the diesel wins on MPG — 23 against 20 for the V6 — and again it loses on annual cost, $3,450 against $3,100. The only engine it beats on running cost is the 5.7-litre V8, and it beats that by a wide margin.

The carbon figure is the one nobody expects

Look at the CO₂ column. The F-150 diesel emits 412 grams per mile. The 2.7-litre petrol V6 emits 401. The more efficient engine emits more carbon dioxide per mile than the less efficient one, because a gallon of diesel contains more carbon than a gallon of petrol. On the Ram 1500 the two are effectively level — 448 grams for the diesel against 450 for the 3.6-litre petrol V6.

If your reason for wanting a diesel is environmental, the tailpipe carbon numbers do not support it in this class of vehicle. If your reason is torque and towing, they are irrelevant. Either way, it is better to know.

Why heavy-duty trucks have no figures at all

Search for EPA fuel economy on a 2018 Ford F-250, a 2018 Ram 2500 or a 2018 Chevrolet Silverado 2500 and you will find nothing. That absence is not an oversight in the data — it is the law.

EPA fuel-economy labelling applies to vehicles up to 8,500 lb gross vehicle weight rating. Above that threshold, manufacturers are not required to publish city, highway and combined figures, and they generally do not. Three-quarter-ton and one-ton pickups sit above the line. So do many heavy SUVs and vans.

This matters more than it sounds, because heavy-duty is precisely where diesel dominates. The trucks where the diesel case is strongest are the trucks where you have the least verifiable data to make it with.

Where diesel genuinely earns its premium

None of the above is an argument against diesel. It is an argument against buying diesel for fuel savings. The real case rests on three things the EPA does not measure.

Torque, and where it arrives

A diesel makes its peak torque low in the rev range, which is exactly where a loaded truck lives. Pulling away with a trailer, holding a grade, or working at low speed, a diesel does it without the engine having to spin up and without the transmission constantly hunting. This is a driving-quality difference as much as a capability one, and it is the reason people who tow regularly rarely go back.

Towing capacity and stability

Diesel pickups are usually rated to tow more, and the difference grows as you move up the weight classes. Beyond the rating, the engine braking available from a diesel with an exhaust brake is a genuine safety feature on long descents, where a petrol truck is asking a lot of its service brakes.

Engine longevity

Diesel engines are built heavier — stronger blocks, larger bearings, higher compression, and components sized for continuous load. Under commercial use they routinely outlast the petrol equivalent by a substantial margin. That said, the caveat matters as much as the claim: longevity is a property of the engine, not of the emissions after-treatment, the turbocharger, the high-pressure fuel system or the electronics attached to it. Those are the parts that generate diesel repair bills, and they do not last half a million miles.

The costs that do not appear in the fuel figure

The purchase premium for a diesel option is substantial when new and remains substantial used, because used diesel pickups hold their value well. On top of that:

• Diesel exhaust fluid. Modern diesels dose urea into the exhaust to control nitrogen oxides. It is a consumable you buy and top up, and a truck that will not start because the DEF system has faulted is not a rare complaint.
• Larger service quantities. More oil, bigger filters, a fuel filter service that petrol trucks do not have.
• Emissions hardware. Diesel particulate filters, EGR systems and NOx sensors are expensive when they fail, and short-trip driving that never lets the filter regenerate is the fastest way to make them fail.
• Injection system. High-pressure common-rail injection runs at pressures that make contaminated fuel genuinely destructive. A bad tank of fuel can be a five-figure event.
• Specialist labour. Fewer shops work on diesels, and those that do charge accordingly.

Set against that, diesel trucks depreciate more slowly, which recovers some of the premium at resale. Whether the whole equation works depends almost entirely on whether the truck does the work a diesel is built for.

The recall and complaint record on 2018 pickups

Fuel type is not the only thing that differs between these trucks. Their federal records differ far more.

The 2018 F-150 carries 19 recall campaigns — the highest count in this group — spread across powertrain, engine, exterior lighting, brakes, latches, tyres, suspension, fuel system, seats, seat belts, structure and equipment. A high campaign count is not straightforwardly a bad sign. It reflects sales volume, and it reflects how readily a manufacturer files. The F-150’s owner complaint file, by contrast, is the smallest in the group: 37 complaints across eight categories, 33 of them against the powertrain, with no crashes, fires, injuries or deaths reported.

The 2018 Ram 1500 has 15 campaigns and 648 complaints across 29 categories, led by electrical system at 157 and engine at 108, with 25 crashes, eight fires and 25 injuries attached. Its recall list includes campaign 20V475000, filed in August 2020, covering the diesel engine specifically, and a separate diesel fuel-system campaign.

Among the heavy-duty trucks, the 2018 Ram 2500 stands out sharply: 10 campaigns, but 2,536 complaints across 26 categories, of which 2,301 name the service brakes. When a single component category accounts for that proportion of a complaint file, it is describing a specific known issue rather than general owner dissatisfaction, and it is worth researching in detail before buying one.

The 2018 F-250 SD records 10 campaigns and 382 complaints, dominated by steering at 243 and suspension at 193 — a very different profile, and one familiar to anyone who has read about steering behaviour on that generation of Super Duty. The 2018 Silverado 2500 is the quietest of the three heavy-duties in the complaint record, with five campaigns and 52 complaints across 18 categories. The 2018 GMC Sierra 1500 sits between them with seven campaigns — four against air bags and three against hydraulic service brakes — and 296 complaints led by powertrain at 125.

Note that none of these patterns divide along fuel-type lines. Steering complaints on a Super Duty and brake complaints on a Ram 2500 are model issues, not diesel issues. When you are comparing two specific trucks, the model’s record tells you more than the fuel it burns. Both are free to look up — our guide to checking a truck for open recalls covers the process, and it takes about two minutes per VIN.

Crash ratings, where they exist

NHTSA’s New Car Assessment Program rates a subset of these trucks, and the rollover figures are the ones worth noting on a tall vehicle.

Two things to take from this. First, the ratings are configuration-specific: a rating for a regular cab two-wheel-drive truck does not transfer to a crew cab four-wheel-drive version of the same model. Check that the configuration you are buying is the one that was tested. Second, heavy-duty pickups are frequently rated only for rollover, or not at all, because the programme’s scope follows the same weight logic as the fuel-economy labelling. A blank in the table is missing data, not a poor score. You can look up any specific configuration through NHTSA’s safety ratings.

Cold weather, short trips and the northeast problem

Climate changes the calculation in ways the sticker never mentions. Diesel fuel gels as temperatures drop, which is why winter-blend fuel and anti-gel additives exist and why block heaters are standard equipment on working trucks — the 2018 Silverado 2500 even carries a recall campaign, 21V496000 filed in July 2021, against its engine block heater. A diesel that lives outside through a northeastern winter needs to be plugged in on the coldest nights, and needs somewhere to plug in.

Short trips are the bigger issue. A diesel particulate filter traps soot and periodically burns it off in a regeneration cycle that requires sustained exhaust temperature. A truck that only ever does eight-mile runs never completes a regeneration, the filter loads up, and eventually the truck goes into a reduced-power mode or needs a forced regeneration at a shop. This is the single most common way an owner turns a well-built diesel into an expensive one, and it has nothing to do with the engine’s quality.

Put those together and a picture emerges of the buyer for whom diesel is genuinely wrong: someone doing a short suburban commute, parking outside, towing a few times a year. That describes a great many pickup owners. It also describes exactly the use case where a petrol V6 is cheaper to buy, cheaper to keep, and — on the EPA’s own figures — no more expensive to fuel.

Buying a used diesel: what to check that petrol buyers do not

If you have decided the diesel case holds for your use, the inspection is different. Add these to the standard used-truck checks:

• Ask how the truck was driven. A diesel that spent its life on short unloaded trips is the worst case for the particulate filter. One that towed regularly on long runs is, counterintuitively, in better health.
• Look for emissions deletes. A removed DPF or EGR system is illegal for road use, will fail an emissions inspection, and is expensive to reinstate. It is also a sign of what else the owner was willing to do.
• Check for DEF system fault history. A scan tool will show stored codes. Repeated DEF or NOx sensor faults are a running expense.
• Cold-start it yourself. Not after the seller has warmed it up. Excessive smoke, extended cranking or a rough first minute all mean something on a diesel.
• Inspect for coolant and oil leaks around the turbo and EGR cooler. These are common and not cheap.
• Read the service history for fuel filter changes. Skipped fuel filters on a common-rail engine are a warning about the most expensive component in the truck.
• Check the frame and underbody for corrosion, especially on a truck from a salt-belt state. Structure complaints appear on both the F-250 and the F-150 records, and a working truck lives outdoors. Our rust inspection routine applies double to pickups.

Everything else — VIN verification, title brands, odometer history, open recalls — is the same process as any used vehicle, and it is set out step by step in our guide to checking a used car’s history before buying.

Frequently asked questions

Do diesel trucks actually save money on fuel?

Not necessarily, and often not at all. The EPA rates the 2018 F-150’s 3.0-litre diesel at 25 combined MPG with an estimated annual fuel cost of $3,200, while the 2.7-litre petrol V6 returns 22 combined MPG at $2,800. The diesel uses less fuel and costs more to run, because diesel is priced higher per gallon. The savings case for diesel rests on capability and longevity, not on the pump.

Why can I not find MPG figures for a Ford F-250 or Ram 2500?

Because EPA fuel-economy labelling applies only to vehicles up to 8,500 lb gross vehicle weight rating, and heavy-duty pickups sit above that threshold. There is no tested federal figure for them. Any MPG number you see quoted for a three-quarter-ton or one-ton truck is an estimate or an owner report, not a certified result.

Is a diesel pickup worth it if I tow only occasionally?

Usually not. Occasional towing within a half-ton truck’s rating is well within what a modern petrol V6 or V8 handles, and you avoid the purchase premium, the DEF consumable, the emissions hardware and the specialist servicing. The diesel case strengthens sharply once you are towing heavy loads regularly or need a heavy-duty truck’s ratings.

Do diesel engines really last longer?

The engine itself typically does, because it is built for continuous load with heavier internals. What does not last as long is everything bolted to it — the turbocharger, the high-pressure fuel system, the particulate filter, the EGR cooler and the sensors that manage them. Those are the components that generate high-mileage diesel repair bills, so “the engine will last forever” is true and incomplete.

Does a diesel truck pollute less than a petrol one?

Not in terms of carbon dioxide per mile, on these figures. The 2018 F-150 diesel is rated at 412 grams of CO₂ per mile against 401 for the 2.7-litre petrol V6, because diesel fuel is more carbon-dense per gallon. On the 2018 Ram 1500 the diesel and the 3.6-litre petrol V6 are effectively level, at 448 and 450 grams. Diesel’s modern emissions advantage is not a carbon advantage.

Which 2018 pickup has the most recalls?

Of the six in our data set, the Ford F-150 has the most with 19 campaigns, followed by the Ram 1500 with 15. Both the F-250 SD and the Ram 2500 have 10, the GMC Sierra 1500 has seven and the Chevrolet Silverado 2500 has five. Campaign counts track sales volume and a manufacturer’s willingness to file as much as they track underlying quality, so read them alongside the complaint record rather than on their own.

What is the biggest red flag on a used diesel pickup?

An emissions system that has been removed or tampered with. A deleted particulate filter or EGR system makes the truck illegal to operate on public roads, will fail an emissions inspection, and costs a great deal to put right. It is also a reliable signal about how the rest of the truck was treated.