Have you ever wondered what happens if you put gas in a diesel engine? Or maybe you have been a victim of this act before, and you experience the effects the hard way (don’t blame yourself or your driver; it happens often).
Either way, mixing gasoline and diesel in a vehicle can give headaches and cause catastrophic engine damage.
Accidentally mixing gasoline and diesel fuel is a common mistake one may think of, especially in a gas station where gasoline and diesel pumps are placed next to each other.
In this article, we’ll discuss at length the possible effects of mixing both fuel types in a vehicle and how to test for gas in diesel fuel.
Understanding Gas and Diesel Fuels
Gasoline
#1. Engine Type.
Gasoline is specifically designed for use in spark-ignition engines, commonly known as gasoline or petrol engines. These engines work on the Otto cycle, where a mixture of air and fuel is ignited by a spark plug.
#2. Ignition Method.
The ignition of gasoline happens through the use of spark plugs. When the piston compresses the air-fuel mixture, the spark plug emits a spark at the precise moment to ignite the mixture. This controlled combustion pushes the piston down, driving the crankshaft.
#3. Physical Properties.
- Lighter Composition: Gasoline molecules are generally smaller and lighter than those in diesel, consisting mainly of hydrocarbons in the C4 to C12 range.
- Volatility: It has a relatively high volatility, meaning it evaporates quickly. This is crucial because the fuel must vaporize for proper combustion to occur within the short timeframe of the engine’s cycle.
- Octane Rating: Gasoline is formulated to have a specific octane rating that prevents premature combustion or “knocking.” Higher octane fuels resist knocking better in high-compression engines.
- Combustion Cycle: Gasoline is formulated to burn within the specific timing and temperature conditions of the spark-ignition cycle, which involves intake, compression, power (combustion), and exhaust phases.
Diesel
#1. Engine Type.
Diesel fuel is used in compression-ignition engines, which operate on the Diesel cycle. Here, the fuel-air mixture ignites due to the heat of compression rather than a spark.
#2. Ignition Method.
Instead of a spark, diesel fuel auto-ignites when injected into the combustion chamber at the end of the compression stroke. The high pressure and temperature cause the diesel to ignite without an external ignition source.
#3. Physical Properties.
- Heavier Composition: Diesel fuel consists of hydrocarbons that are larger and heavier, typically in the C12 to C20 range, giving it a higher energy content per volume.
- Lower Volatility: Diesel does not evaporate as quickly as gasoline, which suits the higher compression and longer ignition delay of diesel engines.
- Cetane Number: Similar to octane for gasoline, diesel has a cetane number that indicates ignition quality; higher numbers mean quicker ignition under compression.
- Energy Density and Efficiency: Diesel’s higher energy density allows for better fuel economy, and diesel engines generally have higher thermal efficiency due to their higher compression ratios.
Key Differences
- Ignition: The fundamental difference lies in how the fuel ignites. Gasoline requires an electrical spark to ignite, while diesel relies solely on the heat generated from air compression.
- Lubricity: Diesel fuel inherently contains compounds that provide lubrication for the fuel injection system and engine parts. This is less of a concern with modern gasoline engines, which have different lubrication systems, but older or specific types of gasoline engines might benefit from additives for lubricity.
These differences lead to distinct engine designs, operational characteristics, and maintenance needs.
Gasoline engines tend to be lighter and less expensive but are typically less fuel-efficient than diesel engines, which are known for their durability, torque, and efficiency but are heavier and often more costly to produce.
What Happens if You Put Gas in a Diesel Engine?
Using gasoline in a diesel engine can lead to a range of detrimental consequences, impacting both the immediate operation and long-term health of the engine and its components.
The incompatible nature of gasoline in a diesel system triggers a chain of adverse effects that can result in severe damage if not addressed promptly:
- Reduced engine performance.
Damage to Engine Components
Engine components can become damaged as a result of using the incorrect fuel.
- Fuel injectors: Gasoline’s chemical properties can damage fuel injectors, affecting their precision and ability to deliver fuel in the correct manner.
- Cylinder walls and pistons: Incomplete combustion can cause hot spots, leading to overheating and potential damage to cylinder walls and pistons.
- Valves and valve seats: Gas contamination can lead to valve sticking or damage to valve seats due to carbon buildup, affecting engine compression and performance.
- Filters and fuel lines: Gasoline can clog fuel filters and lines due to the formation of varnish-like deposits, hindering the proper flow of fuel and potentially causing fuel starvation.
Effects of gasoline in diesel engine
If gasoline is in your diesel engine, it will lead to uncontrollable detonation and a lack of lubrication. It can also cause the engine to stall and damage the diesel pump. Finally, the fuel injectors can fail and severe engine damage can occur, leading to costly repair bills.
Let’s look at these possibilities a little closer.
#1. Uncontrollable Detonation.
The air-fuel mixture in the combustion chamber is ignited differently between the gas and diesel engine. Because incomplete combustion occurs of the gas in the diesel tank, you may see large amounts of black smoke from the tailpipe.
The problem also leads to detonation, which is an explosion of the fuel within the cylinder. This knock or pinging sound is most prevalent during acceleration.
#2. No Lubrication.
Diesel fuel is needed to keep the components of the system properly lubricated. In comparison, gasoline doesn’t offer any lubricating properties.
With a lack of lubrication, the metal components can start to rub together and create friction. This problem leads to abnormal wear of the fuel system parts.
#3. Stalling Engine.
With the combustion occurring at the wrong time and the air-fuel mixture not being used, the computer starts to compensate by making adjustments. The result is a lack of power and decreased performance.
It can get so bad that the engine starts to stall. Plus, the sensors for the computer may become contaminated and stop working properly.
#4. Failing Diesel Pump.
The contamination from the gasoline can cause damage to the fuel pump. Diesel fuel acts as an oil, while gasoline is a solvent.
Without the right amount of lubrication, the pump will fail. You don’t want to damage this critical component, as a new diesel fuel pump can cost $1,500 to $2,500. Even if you could complete the repair yourself, you would need to spend the money on the parts.
#5. Failing Fuel Injectors.
For the same reason that the pump fails, so will the injectors. Without the right amount of lubrication, the injectors are subject to excessive wear.
It won’t take long before damage occurs. When it does, keep in mind that new fuel injectors can cost $350 to $850 each.
#6. Severe Engine Damage.
Whether it’s a lack of lubrication or the change in flash point temperature, serious damage is going to occur to the engine. Even putting 1% of gasoline in a full diesel tank can lower the flash point by 64 degrees Fahrenheit.
This temperature change causes premature ignition that’s going to create massive damage. You may be looking at a new engine if you don’t clean out the system fast enough.
Causes of Gas in Diesel Engine
So, what can cause gas contamination in a diesel engine? There are a few main ways this can happen:
#1. Misfuelling at the pump.
One of the most common causes is accidental misfuelling, where gasoline is mistakenly pumped into a diesel tank. This error can occur due to distractions, confusion or inattentiveness while refueling the vehicle.
#2. Contaminated fuel supply.
Sometimes, gas contamination can occur due to issues within the fuel supply chain. This can include contaminated diesel fuel at the gas station due to improper storage, transportation or handling practices.
#3. Shared fueling equipment.
Shared fueling nozzles or pumps at gas stations might contain residue from gasoline, especially if not properly cleaned between uses. Even a small amount of gasoline left in the nozzle can contaminate the diesel fuel being dispensed.
Sometimes, there are similar nozzle sizes and colors for the diesel and gas fuel pumps at a gas station. This can cause user errors or mistakes when choosing the fuel for a vehicle. Being distracted, tired or in an unfamiliar vehicle can result in this happening as well.
Effects of diesel in a gasoline engine
As gasoline in a diesel engine will cause catastrophic engine damage if left for a long period, diesel in a gasoline engine will cause damage as well.
However, the damages are not much because it’s not as bad compared to the effects of gasoline in a diesel engine. (That doesn’t mean you should mix the fuel).
Most diesel gas station nozzles are usually bigger than gasoline nozzles; they’ll hardly fit in. That makes it less common to put diesel in a gasoline engine accidentally.
#1. Fuel system and plug damages.
Since gasoline fuel systems are meant to transport petrol, putting the wrong type of fuel in it will eventually cause premature failure to the fuel pump, fuel filter, and injectors.
Over time, these components will go bad and require you to replace the entire fuel system components.
#2. Poor/lack of ignition.
A diesel in a gasoline engine will cause poor ignition. This is true; even in real life, gasoline ignites faster than diesel fuel.
#3. Car won’t start.
A large amount of diesel in a gasoline engine will eventually prevent your vehicle from starting. If your car won’t start due to diesel in your gasoline fuel system, the best way of fixing it is by draining out the mixed fuel and refilling it with gasoline fuel.
Long-Term Effects of Misfuelling
If the issue isn’t addressed quickly, the long-term consequences can be severe. Here’s what you might face:
#1. Complete Engine Failure.
If you continue to operate the engine, the cumulative damage can lead to:
- Seized Engine: The lack of lubrication can cause critical components to seize up.
- Costly Repairs: A complete engine rebuild or replacement can run into thousands of dollars.
#2. Increased Repair Costs.
The longer you leave the gasoline in the system, the more components will be affected. This can lead to:
- Multiple Repairs: What starts as a simple fuel issue can escalate into multiple repairs, including fuel pumps, injectors, and even the engine itself.
- Diagnostic Fees: Mechanics will charge for diagnosing the problem, which can add to your bill.
#3. Safety Hazards.
Running a diesel engine on gasoline can create safety risks:
- Fire Risk: Gasoline is more volatile than diesel, increasing the risk of fire, especially if the engine overheats.
- Environmental Concerns: Unburned fuel can lead to increased emissions, which is harmful to the environment.
Gasoline Engines vs Diesel Engines
Ignition Process
The main difference is how they light up the fuel. Gasoline engines use spark plugs to ignite a mix of air and fuel.
On the other hand, diesel engines compress air to super high pressure and temperature, and then inject diesel fuel into this hot compressed air, making it ignite all by itself.
Compression Ratio
Diesel engines have a higher compression ratio than gasoline engines, which means they compress the air in the cylinder to a greater extent. This high compression ratio is what heats the air to a temperature that’s hot enough to ignite diesel fuel.
Efficiency and Power
Diesel engines are usually more efficient and offer more torque at lower speeds, making them popular in heavy-duty vehicles.
On the other hand, gasoline engines are generally lighter and can rev higher, which is why they’re commonly used in “regular passenger” cars.
Emissions
As you could have probably seen, there has been plenty of negative talk about diesel emissions recently. Diesel engines tend to produce more nitrogen oxide and particulate matter compared to gasoline engines, which can be harmful to the environment.
Although modern diesel engines with advanced emission control systems have significantly reduced these emissions. Gasoline engines typically emit more CO2.
Why Gasoline and Diesel Don’t Mix?
Diesel and petrol (gas) are two very different fuels. Diesel is heavier, oilier, and designed to ignite through compression, whereas petrol is lighter and ignites with a spark due to their different combustion properties.
That simple difference can lead to serious engine problems when the wrong fuel is used. Using the incorrect fuel type from diesel and gasoline pumps can result in significant engine damage, including misfiring and costly long-term repairs.
This is why knowing diesel engine basics and how to avoid fueling mistakes is so important.
What do you do if you put gas in a diesel engine?
If you realize you put the wrong fuel into your diesel engine, don’t panic. Acting right away can help you prevent further damage to your vehicle.
- Do not start the engine if you suspect or know that gas has been added to the diesel tank.
- Avoid driving the vehicle to prevent the spread of contaminated fuel.
- Contact a professional mechanic or technician to schedule service.
- Take notes of details, including the amount of gas added if known.
Taking these steps is important and will help ensure that you get your vehicle running properly as soon as possible!
What to Do If You Accidentally Put Gas in a Diesel Engine?
A lot of people are wondering what happens when you put gas in a diesel engine. If you accidentally put gasoline in a diesel engine, immediate action is crucial to minimize further damage. First and foremost, here’s what you need to do:
- Stop Immediately: If you realize you’ve misfuelled gasoline in diesel engine, stop the engine as soon as it’s safe to do so. Refrain from driving the vehicle to prevent further damage.
- Avoid Turning the Key: Keep the ignition off to prevent fuel from entering the engine.
- Don’t Start the Engine: Avoid starting the engine to prevent the gas in diesel engine from circulating further.
- Call for Assistance: When accidentally put gas in diesel engine, contact a professional mechanic or towing service right away for help. When assistance arrives, inform them about the misfuelling incident and that there’s a gas in diesel engine.
- Drain the Tank: The technician will likely drain the fuel tank and fuel lines to remove the gasoline or water in tank if contaminated. Or you can do it yourself, empty the fuel tank completely by either using a siphon pump or removing the drain plug from the tank.
- Check for Damage: Assess if any damage has occurred, and address it promptly.
- Refill with Diesel: After draining the gasoline in a diesel engine, refill the tank with diesel fuel.
- Test Drive: Once refueled, the technician may conduct tests to ensure the engine operates correctly.
After draining the fuel tank, inspect the diesel engine for damage from misfuelling. Components like injectors, pumps, and seals may be compromised if gasoline is introduced into the diesel tank.
Cleaning or replacing damaged parts is essential for optimal engine performance and longevity.
Preventive Measures to Avoid Future Misfuelling Mishaps
Preventing misfuelling mishaps requires a combination of practical strategies and heightened awareness. These are some preventive measures for avoiding future misfuelling:
- Label Fuel Caps: Clearly label the fuel caps with the type of fuel the vehicle requires to avoid confusion.
- Educate Drivers: Provide training and reminders to drivers about the importance of using the correct fuel.
- Install Diesel-Only Nozzles: Use diesel-only nozzles incompatible with gasoline pumps to prevent misfuelling.
- Implement Fuel Management Systems: Utilize fuel management systems that monitor fuel usage and provide alerts for unusual activity.
- Regular Maintenance Checks: Conduct routine checks to ensure fuel caps are secure and there are no signs of tampering or damage.
- Storage Separation: Store diesel and gasoline in separate, clearly marked containers or tanks to prevent accidental mixing.
- Color Coding: Use color-coded equipment or labels to differentiate between diesel and gasoline containers.
- Training for Fuel Handlers: Train fuel handlers on proper procedures for handling and dispensing fuel to minimize errors.
The risk of future misfuelling incidents can be significantly reduced by implementing these preventive measures and maintaining strict fuel management practices.
FAQs.
Q: What’s a worse case in diesel in a gasoline tank?
If you accidentally put diesel in a gasoline tank, the engine will run smoothly until all the gas in the line gets used up.
At this point, the engine will run sluggishly or shut down. Gasoline engines are designed to combust petrol, so the engine may start but won’t stay running, or it may not start at all.
Q: Will a small amount of gas hurt a diesel engine?
It all depends on the quantity. So, can you dilute diesel with gas? 1% of gas in a diesel engine may not cause any damage.
However, a bigger amount of gas in diesel can cause catastrophic engine damage. This is because a bigger volume of at least 5% will prematurely ignite during the combustion cycle.
Q: Why are gas engines better than diesel?
Generally speaking, diesel-powered engines are more powerful than gasoline ones. This is because diesel engines carry more energy than petrol engines; a quart of diesel fuel has 30% energy more than gasoline.
Diesel engines provide more torque than petrol-powered ones. Diesel engines also outperform gasoline-powered engines and offer better fuel economy. Then, why are gasoline engines better than diesel engines?
Diesel engines suffer performance issues when you pour in black diesel, bio-diesel, or any type of enhanced diesel fuel. This can damage your injector pump and nozzles – and these components are very expensive.
Another reason why people consider petrol-powered engines are, that you can hardly differentiate well-refined diesel fuel from black and bio-diesel.
Q: How can you tell gas from diesel?
Diesel and gasoline fuels have different colors. If you can’t differentiate the colors, just smell them.
They have a different smell, if you can’t tell the difference from the smell, deep your fingers in them. Diesel is oilier, while gasoline will evaporate quickly and leave your fingers cold and white.
Q: Can you put diesel in a container that used to have gas?
A small amount of diesel won’t prevent your gasoline from burning as it should. It won’t make any difference to the engine’s smooth operation. However, before using the container, make sure you pour out all the gasoline in it.
Q: How much does it cost to flush diesel out of a car?
Depending on your car make and model and the quantity of diesel in your gas fuel system, you can spend around $400 to $1000 on a fuel system flush, which is what you need to salvage your engine from catastrophic damages.
Final Thoughts
Now that we’ve uncovered what happens if you put gas in a diesel engine, it is of utmost importance to take precautions.
Accidentally if you mix these fuels, do not start your vehicle. Contact a mechanic or dealership to toll the vehicle. The mechanic needs to completely drain and flush the fuel system to get your vehicle back on the road.