Diesel Vs. Gas Truck – Which Is Best For You?

Diesel Vs. Gas Truck – Which Is Best For You?Wondering whether to get a diesel or a gas pickup truck to tow your travel trailer or 5th wheel with? Is one type better than the other? We were wondering the same, so did the research and have some answers for you.

If you're not towing - a gas truck is the way to go. For towing a heavy rig - a large trailer or 5th wheel - you should consider diesel as an option. The heavier the rig - the better will a diesel truck be for you.

There's more to the decision than just towing though. Keep reading for an in-depth evaluation of the pros and cons of each option.


What's the difference between a gas truck and a diesel truck?

Simply put, a gas-driven truck - sometimes referred to as a gas truck - uses gasoline to run its engine. A diesel truck is simply a vehicle that runs on... you guessed it, diesel!

Gasoline - aka petrol in Europe - and diesel are two different derivatives of crude oil. The two substances are chemically different, even though both are used as liquid motor fuel. For our purposes, there are only two things that we need to know about gas vs. diesel -

  1. Diesel boils and self-ignites at a higher temperature than gas.
  2. Diesel is generally cheaper than gas (though that can vary).

Which pickup trucks run on diesel and which run on gas?

As a rule of thumb - the heavier the truck, the more likely it is to run only on diesel. Light-duty trucks are almost always available with gas or diesel engines. Let's take a look at a few examples.

Of the smaller, aka mid-size trucks -

  • The Honda Ridgeline runs on a 280-HP, 3.5-Liter, V-6 gas engine.
  • The Chevrolet Colorado usually has the 3.6L V6 VVT  gas engine but is also available with the  2.8L Duramax®Turbo-diesel engine.
  • The popular Toyota Tacoma comes with a 3.5-Liter V6 gas engine.

In the half ton trucks class

  • The Ford F-150 offers owners a choice between no fewer than six types of engines - five of them are gas engines and only one is a diesel engine, the New 3.0L Power Stroke® Turbo Diesel.
  • The Chevy Silverado 1500 runs on a 5.3L V8 gas engine.
  • Dodge Ram 1500 offers several models but all of them with gas engines (either V6 or V8).
  • GMC's Sierra 1500 has a standard 5.3L EcoTec3 V8 gas engine (other V6 and V8 engines are optional).

And now to the heavy duty department...

1-ton trucks engine types

  • The Ford F-350 runs on the 6.2L Flex Fuel V8 gas engine as its standard engine but also has a V8 Turbo Diesel engine.
  • Chevrolet offers owners of Silverado 3500HD and 2500HD a choice between the VortecTM6.0L V8 gas engine and Duramax® 6.6L V8 turbo diesel engine.
  • The Ram 3500 trucks come with the 5.7-Liter V8 HEMI® gas engine.
  • Finally, the GMC Sierra 3500 has the Vortec® 6.0L Variable Valve Timing V8 SFI gas engine.

How do these engines work?

To understand the difference between a gas truck and a diesel truck, we have to understand the differences between these two types of engines. The thing to remember here is that both of these engines focus on the same goal: Transforming chemical energy into mechanical energy. In other words, taking oils - packed with energy -  and make them move something that will eventually push the wheels of a vehicle for us.

Both types of engines run through a cycle that basically takes a small amount of fuel to cause an explosion. That explosion then releases the energy in the oil and converts it into kinetic (movement) energy. The difference between the engines lies with the type of fuel used and how exactly the engine "blows up" or combusts the fuel.

Here's what the four-stroke cycle looks like

  1. Intake stroke - the engine draws in either a mixture of gasoline and air or just air (in a diesel engine).
  2. Compression stroke - the air (or fuel-air mixture) is compressed. The chamber within our cylinder gets sealed up and a heavy part called "the piston" pushes down on the contents, forcing it to lose volume and as a result - heat up.
  3. Power stroke - an explosion releases energy that pushes the cylinder away, transferring that energy on to the crankshaft.
  4. The exhaust stroke  - the piston pushes out the remaining fumes and gases, releasing them into the atmosphere via the exhaust.

Ok, so now that we know how a 4 stroke engine works, what about the difference between a diesel engine and a gas engine?

How does a gas engine work?

Gasoline is fairly safe to use because it does not tend to blow up on its own. Yes, it is very flammable but if you just heat it up for a long while, you'll have to reach a very high temperature before it self-ignites.

That's why two things happen in a gas engine (but not in a diesel one).

  1. During the intake stroke, the cylinder takes in both air and gasoline. That mixture is already more "loaded" than gasoline on its own.
  2. Gas engines use an additional spark to light up the mixture inside the combustion chamber. The piston does compress the gas, raising the temperature and making it more "explosive" but it still needs the additional ignition process with every cycle. That's why gas engines have a spark plug. Diesel engines don't need one.

Here's a good short animation of a gas engine at work. You can watch it without sound - the captions do the job -

How does a diesel engine work?

Diesel is "heavier" than gasoline. Richer in oil chains, Diesel is a more condensed and energy-rich liquid. It's actually less flammable than gasoline at room temperature. 

During the intake stroke, a diesel engine takes in only air. During the compression stroke, that air is compressed and becomes super hot - over 500 degrees hot! In a diesel engine that's when a squirt of diesel oil is squirted right into this super hot air to create the explosion.

The compression ratio in a diesel engine is much higher just before the explosion, making the combustion more volatile. That's why these engines have to be heavier (to sustain the impact). It's also why they tend to be louder and more "jerky", especially with the older engines.

Compare that to the same stroke in a diesel engine -

Diesel engines are also known as internal combustion engines, CI engines, or compression-ignition engines. The compression itself generates the combustion - without need for external ignition.

So, which engine is stronger?

Now that we know how a diesel engine differs from a regular gas engine, comes the big question: Diesel Vs. Gas engines – which is better for your truck?

Diesel is more powerful

Why are diesel trucks more powerful? In a word: Torque.

Torque is the amount of force that the engine transfers to the crankshaft. Because of the more volatile combustion, as well as the way the cylinders of a diesel engine are constructed, a diesel engine provides more torque.

What that means is that the engine peaks its power sooner than a gas engine, while using the same gear. When the engine needs a lot of power a diesel engine can provide the same amount of power with lower RPM (rounds per minute). In other words, more force with less effort.

And when does an engine need a lot of power? When it's trying to accelerate or decelerate a vehicle which carries or pulls (tows) a very heavy weight.

So, diesel is the answer for towing, right?

Yes, and No.

After all, everything has pros and cons... Diesel engines may be more powerful and provide more torque but they're also heavier and more expensive.

And here's the thing -

Some modern gas engines can be as powerful as diesel engines. 

Yup. We kept saying diesel was more powerful for the same size of engine. But who says you have to compare apples to apples?

In the past, yes, diesel engines were pretty much the only option when it came to powering pickup trucks. Today, we have brand new types of gas-powered engines where additional cylinders can provide more torque. We're talking about gas-operated V6 and V8 engines. These engines are larger in volume than the engines you'll find in a regular sedan, so they provide a whole lot more torque and horsepower.

Gas engines can be very powerful - to a point.

At some point, size does matter.

Diesel engines can have larger cylinders. Really huge ones, actually. In some heavy machines, like huge industrial boats, diesel engines have cylinders a person can walk into. You can't do that with gasoline engines because gas isn't as safe when stored and used in these larger quantities.

What's more, getting more cylinders of the same size also has its limits. The more cylinders you have, the harder it is on the crankshaft to receive the energy from multiple sources. The V-shaped engines solve part of the problem as they put the cylinders closer to each other and have them attached at a central point (hence the V-shape). It's still challenging and you can't get away with too many of them.

With diesel, you can get larger cylinders and so get more and more powerful engines. That's why all of the really huge trucks - box trucks and semi-trailers - they always have diesel engines.

So, the bottom line for this section of our review is:

For light-duty tasks, including towing a lightweight trailer, you can certainly find gas engines that will be up to the task. Towing heavier rigs could mean you need a stronger engine - which would mean diesel. That's in terms of engine power alone.

Now let's look into other parameters which could affect your choice of engine.

Diesel vs. Gas: Fuel Efficiency

Both diesel and gas engines have come a long way in the past decades. They're stronger, more reliable and more fuel-efficient. Even with improved efficiency in gas engines, diesel rules when it comes to getting the best mileage out of a gallon when towing. However, it's a close call and for people who don't tow or haul, the difference is minimal.

It's always a good idea o check fuel efficiency stats for the models you're considering. Just make sure you're comparing modern engines. An efficient 2018 EcoBoost V8 engine is going to be more fuel-efficient than a 15-year-old diesel engine.

As for how much the gallon costs - that too depends, of course. Your location matters as well as the type of gas station you use, and of course market fluctuations. As a rule of thumb, diesel costs about the same as mid-grade gasoline. Here's a screenshot I took in July 2018 from the AAA's website -

Cost of diesel vs gas

Diesel is approx. 10% cheaper than premium gas - and with both types of fuel, prices fluctuate.

Gas vs. Diesel: Price of Engine

This is where gas engines are definitely better. They are cheaper.

Take, for example, a Ford F-150 Lariat with the same length of bed and cab.

This is the Turbo diesel offer -

Price of a diesel Ford truck And this is the gas engine offer (3.5L EcoBoost® V6 Engine with Auto Start/Stop Technology):Price of a gas Ford Truck

The diesel version of the same truck will cost you about $2,500 more! And that's when comparing the more expensive gas engine - Ford has cheaper options there.

What's more, the difference in price will be even higher if you're buying a heavy duty truck. And many times, a diesel engine will be available only in models with an upgraded transmission. Which means that overall - the truck will be far more expensive.

However, diesel engines will retain their value for longer.

According to Steve Jansen, diesel engines have a longer lifespan than gas engines. This is due to their intense cylinder pressure and high-compression ratios. This ensures they get the best pistons, crankshafts, valves, and cylinder heads on the market. Besides that, “a diesel engine’s exhaust system will outlast a gas engine exhaust system because diesel fuel exhaust is not as corrosive as gasoline engine exhaust,” adds Jansen.  

Which translates into resale value. If you buy a diesel truck and then sell it a couple of years later, you're going to find that the truck hasn't gone down in price as much as its gas counterpart. In essence, you put more money into the truck when you buy it - but you also recoup most of your investment when it's time to sell. The engine itself does not depreciate as much as its gasoline counterpart.

Cost of owning a diesel truck vs gas

So, diesel engines are more expensive - but maybe they're cheaper to maintain?

Not really. These engines are hardy and built to last, so if you treat them well, they won't break down on you. However, treating them well includes several extra costs -

Diesel Exhaust Fluid

This is an additional maintenance routine that's needed for diesel engines. You'll need to add Diesel Exhaust Fluid - also known as DEF or DEF fluid - every few thousands of miles. Just how often will depends on your truck and what you do with it. If you're towing or hauling weights, you should add DEF fluid more frequently, but as a general rule, it's a lot like an oil change - once every few months.

You can get DEF fluid by the case - even on Amazon - or at the pump in gas stations which serve a lot of trucks.

Oil Changes

An oil change on a diesel pickup is more expensive. That's because diesel engines are volatile and require extra lubrication to withstand that powerful internal diesel combustion. Which means more oil goes into the engine at every oil change. Also, in some places, they'll top up your DEF fluid when you come in for an oil change and charge you for both by the case.

Still, according to this study, the overall cost of maintaining a diesel engine, in the long run, isn't too bad, as long as it is well-maintained.

Environmental Considerations

Diesel trucks used to have a notoriously high carbon footprint, releasing more nitrogen oxide and other emissions. Today, the environmental footprint of the two is more closely related, so there’s no need to exclude diesel trucks if you’re eco-friendly.

With an older truck - check the specs and see if you're comfortable with the level of contamination produced by the vehicle.

So, what's the bottom line?

It all depends on your needs.

How much you're going to tow or haul

And yes, we're talking about towing and hauling but it depends how much you're going to pull.

With modern gas engines, you can tow lightweight 5th wheels or travel trailers with a gas engine. It's only with a heavy rig that you may need the extra torque of a very strong high-volume diesel engine.

The type of terrain you'll be driving

Torque - the strong suit of a diesel engine - is important when accelerating, decelerating or when driving uphill or downhill.

If most of your towing is done on even roads with no incline, then torque will mostly matter when you're accelerating - mostly in the beginning of a drive or after a stop. If you don't mind having a slow start, less torque will be fine.

However, if you're going to be hauling or towing a heavyweight uphill, torque could become a major issue. You're going to need a strong engine. And if your rig is extra heavy, that may mean a diesel engine.

In the end, each pickup truck model comes with towing restrictions. The model you buy must be a good fit for your towing needs. As long as you're within those limits (with some to spare), you could go with either a diesel or a gas engine for towing.

See for example -

How much can you tow with a Ford F-150

How much can you tow with a Chevy Silverado?

Taking the year of make into account

Many people who think diesel is required to tow a trailer have older pickup trucks in mind. Engines have come a very long way in the past couple of decades. Fuel injection technology and computerized engines make modern gas engines efficient and strong. Diesel engines are also better than they were a couple of decades ago.

So, if you're considering either a diesel or gas truck, you should take the vehicle's age into account and check the specs of the specific engine it runs on.

In summary

We hope you found the information in this post helpful. The choice of engine is important when buying your next pickup truck, especially if you're about to tow an RV with it. We have a few more posts on the topic which you might find useful, but first, a quick survey question for you -

What's your current (or future) pickup truck -

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For more reading, check out these posts -

Truck engine sizes and what they mean for you as an owner

4wd vs 2wd truck - which should you choose?

When is the best time to buy a pickup truck

Which Full-Size Pickup Truck is the Safest?

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