Jet fuel and diesel share some similar properties, so it’s reasonable to wonder if jet fuel can power a diesel engine. However, there are some key differences you need to consider before pouring aviation fuel into your truck.
In this in-depth guide, as a professional diesel engine parts supplier, I’ll cover everything you need to know about using jet fuel in diesel vehicles, including:
- What’s actually in jet fuel
- The risks and downsides of using jet fuel in diesel engines
- Additives that make it safe(r) to use jet fuel
- Expert opinions on whether you should use jet fuel in diesel vehicles
Plus I’ll answer common questions like:
- Can you run 100% pure jet fuel in a diesel engine?
- What ratio of jet fuel to diesel is safe for diesel engines?
- Will using jet fuel void your engine warranty?
By the end of this guide, you’ll know whether or not you can — or should — use jet fuel to power your diesel vehicle.
What’s Actually In Jet Fuel?
There are a few different types of jet fuel used in aviation:
Avgas – Used in spark-ignition engines. The most common type of avgas contains tetraethyllead, giving it a high octane rating. Avgas comes in different grades depending on the lead content. Many airplane engines require leaded fuel.
Jet A – The most common type of jet fuel. It’s composed of hydrocarbons like kerosene and has additives like anti-icing agents added. Jet A freezes at -40 °F.
Jet A-1 – Similar to Jet A but with a lower freezing point (-53 °F), allowing it to be used in colder climates. The most widely available and used jet fuel today.
Jet B – Higher flash point than other jet fuels, allowing better performance in extremely cold temperatures. But Jet B is rarely used in commercial or military aircraft due to its hazardous nature.
So those are the basics on what powers jet airplanes high up in the sky today. But should that same aviation fuel be used down here powering diesel trucks, buses, boats, and generators? Let’s dig into that next.
Can You Run Jet Fuel In a Diesel Engine?
The short answer is yes, you can successfully run jet fuel like Jet A or Jet A-1 in a diesel engine.
But jet fuel isn’t necessarily the ideal fuel for diesel engines powering vehicles and equipment on land. And there are some important downsides to be aware of before filling up your next truck or generator with aviation fuel.
Key Differences Between Jet Fuel and Diesel
While diesel and jet fuel share some similar characteristics, there are some key differences between them:
- Sulfur Content – Jet fuel contains far higher levels of sulfur than diesel fuel today. Some types of jet fuel have over 300 times the sulfur as ultra-low sulfur diesel fuel.
- Lubricity – Jet fuel doesn’t provide the same level of lubrication as diesel fuel. Using jet fuel long-term can cause faster wear in fuel injection components.
- Additives – Diesel fuel has additives specifically formulated to prolong engine life. Jet fuel’s additives are more focused on performance at high altitudes.
Biggest Downsides to Using Jet Fuel in Diesel Engines
Because jet fuel and diesel aren’t perfectly interchangeable, there are some potential downsides associated with using jet fuel to power diesel vehicles and equipment:
- Reduced engine lubrication leading to faster wear and tear
- Higher sulfur content accelerating corrosion in engine components
- Invalidation of factory warranties due to using incorrect fuels
- Potential engine damage over long term use without additives
- Lower performance compared to purpose-made diesel fuels
So while diesel engines can burn jet fuel, it’s generally not recommended without taking additional steps to make it safer. Which leads us into…
Making Jet Fuel Safe(r) For Diesel Engines
If you have access to free or discounted jet fuel, you might be tempted to use it in your diesel vehicle or equipment.
While the risks still exist, there are a few things you can do to help mitigate the downsides of using jet fuel instead of diesel:
Use Fuel Additives
Adding specific chemicals to jet fuel can help counteract some of the key differences compared to diesel. Some popular additives include:
- Cetane improvers – Helps increase combustion efficiency. Important because jet fuel has a lower cetane rating.
- Lubricity agents – Provide extra lubrication for pumps and injectors. Useful because jet fuel isn’t as naturally slippery as diesel.
- Anti-corrosion additives – Combats damage from sulfur and other contaminants.
Following dosage instructions for these additives helps make jet fuel much more viable as a diesel alternative.
Only Use Jet Fuel/Diesel Blends
Rather than relying on jet fuel completely, many experts recommend blending it with traditional diesel:
- “I would not mix it more than 50% [jet fuel].”
- “When winter fuel is blended its usually around 65 to 70% no 2 [diesel] and 30 to 35% no 1 [jet fuel].”
This blended approach provides some of the cost benefits of jet fuel while limiting potential issues like corrosion.
Change Oil More Frequently
Used motor oil analysis has shown fuel dilution is a leading cause of some diesel engine damage according to the ACEA. And jet fuel is more prone to diluting and breaking down oil than diesel.
By changing engine oil more frequently than the factory recommendation when running jet fuel blends, you help flush out contaminants before they can negatively impact engine internals.
Expert Opinions: Should You Use Jet Fuel in Diesel Engines?
With the risks and mitigations covered, what do experts think about using jet fuel in diesel vehicles and generators? Here are some key opinions and recommendations:
“Diesel road vehicles will run perfectly well on Jet A, but long term problems will arise” – Commercial airline captain
“I would not mix it more than 50%. Jet A, no1 fuel oil, Kero, K1 all come out of the same tank at the load rack.” – Ford diesel technician
“If its jet A then yes you can run it but not alone. I would not mix it more than 50%.” – Diesel mechanic
The key theme across experts seems to be that while jet fuel can technically be used in diesel engines, it requires compensating steps like additives and blended fuels. And even then, long term reliability concerns still remain.
So rather than viewing jet fuel as an outright 1:1 replacement or upgrade over diesel, it’s better thought of as a supplementary fuel for limited or occasional use if you happen to have easy access to it. But expect to put in more maintenance work and part replacements along the way if you regularly feed your diesel equipment a diet of jet fuel.
Frequently Asked Questions
Here are answers to some of the most common questions people have about running jet fuel in diesel vehicles and generators:
Can you run 100% pure jet fuel in a diesel engine?
It’s possible to run pure, unblended jet fuel like Jet A or Jet A-1 in a diesel engine, but general consensus is that long term reliability will suffer over time. Issues like fuel pump wear, premature engine corrosion, and invalid warranties make 100% jet fuel an undesirable option without additives or relatively frequent oil changes.
What ratio of jet fuel to diesel is safe for diesel engines?
Most experts recommend limiting jet fuel to 50% or less when blending with traditional diesel fuel. Common blends are in the range of 30% jet fuel / 70% diesel which helps minimize issues while benefiting from jet fuel’s lower cost in some situations.
Will using jet fuel void your engine warranty?
Using incorrect fuels like jet fuel in place of recommended diesel blends very likely voids manufacturer engine warranties. Make sure you check with your owner’s manual or dealership to understand potential warranty implications before putting jet fuel into a modern, computer-controlled diesel vehicle.
Conclusion
While diesel engines can technically burn jet fuel without modifications, there are good reasons why jet fuel and diesel are purpose-made for aviation and ground transportation respectively.
Significant differences in sulfur content, lubrication, and additives mean most experts view jet fuel as an inferior fuel choice in diesel vehicles and equipment from a reliability standpoint.
If you have access to discounted jet fuel, limited blending with traditional diesel along with supplemental additives and accelerated maintenance make using it more viable. But expect to make some tradeoffs in engine longevity by using jet fuel to power your diesel vehicles or generators.
Hopefully this guide has covered everything you need to know around substituting jet fuel in place of standard diesel. But what questions or feedback do you have from your own real-world experience using jet fuel or diesel alternatives? Leave your thoughts below!