Will a Little Gas Hurt a Diesel Engine? [What Happens If You Put Gas In a Diesel Engine]

Is mixing gasoline and diesel in your car can give you a headache? Does it hurt to do this?

If you mix even a small amount of gas in a diesel engine, the diesel fuel will flare early in the engine, causing harm to the vehicle. Combining gasoline and diesel fuel is typical, particularly in petrol stations with closed gasoline and diesel outlets.

Pairing gasoline and diesel in a car can create headaches and severe engine damage.

This article will let you know if a little gas will hurt your diesel engine. We have researched deeply so that you can have the knowledge that you need in this matter.

There may be days when you can accidentally mix gas in your diesel engine. In times like this, you may not know what to do so we got you covered.

At the end of this article, you will be equipped with the following:

  • Know what to do when gas is mixed with diesel in your car
  • Have some tips so that you can have a better fuel system
  • Be knowledgeable about gas and diesel
  • Can do what is best for your car fuel always

If you want to know more about this topic, you can watch the following video:

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What You Can Expect When You Mix Gasoline and Diesel?

Maybe you have been a victim of mixing gasoline with diesel. This may be a common mistake that happens in gas stations.

Most times, gasoline and diesel pumps are close to each other so you may commit the mistake of mixing them. You do not have to blame yourself when this happens but be aware that this can bring extreme damage to your engine.

It has great effects that can destroy your engine. So, you need to have the right knowledge about fuel types to not mix them.

It is not advisable to pair gas with diesel. It can be a huge problem. But to know if gas will hurt your diesel engine, you must know the amount of gas that you have put in your diesel engine. This will be the question.

Depending on the amount of gas, your diesel engine can be damaged. If you are to ask if diesel can be diluted with gas, the answer relies on the amount of gas that you can mix with it.

If you only mixed 1% of gas, this will not cause any harm to your engine. But if it is in a bigger amount, this can be catastrophic. 5% of gas can cause ignitions and will not be good for your combustion cycle.

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Diesel engines can be more powerful than gasoline engines. But pouring a different kind of fuel into it can damage its injector pump. Repairing this component is very costly. So, mixing gas with diesel is not a very good idea.

Do you want to know more about what will happen if you mix gasoline and diesel? Watching this video can give you more knowledge.

Putting Gasoline In A Diesel Car – What Happens?

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How Do You Know That You Have Put the Wrong Fuel?

How do you know that you have mixed gas with diesel? Here are some of the alternative ways that you can notice:

  • You know your car is in good condition but it stops out of nowhere.
  • You can find a difference as you start the engine and whenever you drive.
  • The car has no power and you cannot start the engine.
  • It is hard to turn off the engine.
  • The engine has a loud sound especially when you have a heavy load.

Gasoline’s Impact On a Diesel Engine

You may be able to preserve your engine from major harm if you catch these issues quickly. But, if you continue to drive for an extended length of time with mixed or incorrect fuel in your diesel gas tank, here are three symptoms you might experience as you drive.

● Lack of Lubricant

Diesel is a type of oil and gasoline is a solvent. Mixing gasoline with diesel can cause a lack of lubrication.

Your vehicle can have metal-to-metal contact because of a lack of lubricant. With the metal rubbing against each other, this can damage your engine parts.

Diesel fuel is what is intended for a diesel engine. Only diesel fuel has the power to lubricate.

This can give resistance so that your engine will not be harmed.

● Getting Black Smoke

Diesel and gasoline have different degrees of centigrades in temperature. You need 40 degrees centigrade for gasoline.

On the other hand, you need 52 degrees centigrade for diesel. This means that it will be hard to combust gasoline in a diesel engine.

The result will be unburned fuel. And this can be in a great amount! Because the fuel is unburned, black smoke can be formed in the exhaust tailpipe. This can be embarrassing for you.

This is also because the black smoke gives a bad smell. Also, this will be bad for your fuel system. It can be clogged because of soot.

● No Combustion

Gas will not burn in a diesel engine. No spark will spark the diesel engine after you have poured fuel.

Thus, the fuel system will not have any combustion.

● No Ignition

Diesel engines and gasoline fuels are not designed for each other. There will be no ignition in diesel engines with gasoline fuels.

To ignite the fuel, a spark is needed. But this will not be that possible with gas in a diesel engine.

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If ever there will be an ignition, it will be so little. This will not be enough for a smooth engine operation.

● Destroyed Fuel System

Your fuel pump and fuel filters can be harmed if you will put gasoline in your diesel gas tank. It can destroy your fuel system.

Its components like fuel filters, fuel pumps, and fuel injectors will not work properly. If you need good performance from your car, you have to replace the whole fuel system.

● Getting Shock Waves

Unusual detonation can occur when you put gasoline in a diesel engine. Shock waves can be formed that can harm engine parts like wrist pins, con rods, crankshaft, and pistons.

Shock waves can give engine knocking that will not be good for your car.

● Engine Failure

By having the common mistake of mixing gas with diesel, your engine can be salvaged. Driving with mixed gasoline and diesel can cause damages that are beyond repair.

The components of your engine will have entire damage. Replacing it can cost you a lot of money.

● Hesitation

If the diesel is contaminated, the cylinder will shut down. Your vehicle will stutter and you will have hesitations.

● Check Engine Light

Gas can ignite spark plugs. It can make the check engine light explode.

Petrol vs. Diesel Engines: What’s The Difference?

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Before letting your curiosity about putting gas in a diesel engine run wild, you should be knowledgeable about the difference between petrol and diesel engines.

If you have an idea about these things, you should be able to know if it is safe to put gasoline on a diesel engine.

Stroke Cycle and Compression Ratio

Diesel engines are low revving and more fuel-saving than petrol engines. While both engines operate on the same four-stroke cycle, these are the following:

  • Suction
  • Compression
  • Power Stroke
  • Exhaust Stroke

You must be aware of the self-ignition temperature by which an air-fuel combination may spontaneously ignite even without the assistance of a spark plug owing to compression alone. 

Body Structure

Another vital difference is the lack of a throttle body of a Diesel engine. If you step on the accelerator pedal, the fuel injectors will supply more diesel to create more power.

Petrol engines, however, need a throttle body to allow more air to give access to the engine. 

Engine Breaks

Motor deceleration occurs when you lift off the throttle in gear to slow down the engine in a gasoline vehicle. The body shuts down because you raise the throttle, creating a power vacuum between the throttle body and the cylinders to slow the car down.  

In a diesel engine with no throttle body, engine braking occurs during the compression stroke, where the exhaust valve is open to let go of the pressurized air. 

The Efficiency of Diesel Engines 

Diesel has more energy than petrol, containing 15% more energy by volume. They’re also more efficient because of their thermal gains obtained by igniting the air with high compression.

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Also, they tend to be turbocharged, which is an added factor.

The Difference Between Gasoline and Diesel

There are distinctions between gasoline and diesel. For one thing, their colors are different.

They are different in odor. If you will put a small amount in your finger, you will know whether it is gas or diesel.

Gasoline can evaporate quickly while diesel is oily.

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The following are some of the distinct differences between gas and diesel.

1. Reliability

Fewer parts of diesel engines can malfunction. It can give more miles before it can need repairs.

It can cost you a lesser bill when something is wrong.

2. Efficiency

More energy can be found in diesel engines than in gasoline engines. By volume, it has 15% more energy.

This makes it more efficient than gasoline engines. Another factor is that they can be turbocharged.

Diesel engines are better in fuel economy. Their engines operate with a higher efficiency number.

A low compression ratio can be found in gasoline engines which makes them have less fuel efficiency.

3. Power

Diesel engines do not have much horsepower. But it has a lot of torque that can make the vehicle run well.

So, diesel engines are good for trucks with heavy loads that need a lot of torque. But they are not good on sports cars which need a lot of power.

On sports cars, gasoline engines are more recommended.

4. Fuel Injection

Fuel injection differs in diesel engines and gasoline engines. Their port injection systems are different.

With diesel engines, the fuel is poured into a cylinder. They have sensors that can make your car start more efficiently.

5. Stroke Cycle

Diesel engines and gasoline engines differ in intake stroke, compression stroke, power stroke, and exhaust stroke.

6. Engine Breaks

In a gasoline engine, deceleration can occur. There can be a power vacuum in the throttle body or cylinders which can cause the car to slow down.

On the other hand, engine braking with a diesel engine can happen through compressions because it has no throttle body. It should give out the pressurized air in its exhaust valve.

7. Body Structure

A diesel engine has no throttle body compared to gasoline. Its fuel injectors can give more diesel for the car to have more power.

A gasoline engine, on the other hand, requires a throttle body that can give air to its engine.

8. Compression

You can save more fuel with diesel engines than with gasoline engines. They are also low revving.

Though they both operate in compression, suction, exhaust stroke, and power stroke, the ratio of work is different.

9. Ignition 

A spark plug gives ignition in a gasoline engine. A diesel engine has no spark plug.

The cylinder in a diesel engine gives the self-ignited temperature. The heat and pressure can be formed when the fuel is injected into the cylinder.

10. Durability

Diesel engines are more durable than gasoline engines. That is why diesel is more used in trucks.

It can give more miles than gas. It also needs less maintenance and repair.

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There is a life expectancy of 250000 – 300000 miles with diesel engines. Its engine design is more durable.

11. Cost of Ownership

The cost of ownership of diesel engines is lower. Diesel engines need less maintenance which can cost you less money.

Gasoline engines need more fuel. It also requires frequent maintenance.

Though, a vehicle with diesel can cost you more money to buy.

Testing Gas in Diesel Engine

You must shut down your car if you have put in the wrong fuel. You can avoid any fire or explosion.

When you call the mechanic, you should have a fuel sample to send to the laboratory. They can have a gravity test to check if you have mixed diesel with gas.

They will use a technique to avoid cross-contamination. They have the right equipment to have the best method that will be best for your car.

What To Do When You Have Put Gas on Diesel Engine

● Check the Manual

The manufacturer’s manual can make you know the right type of fuel that you should use. Then have a gas cap according to what the manual has instructed.

● Have a Misfuelling Device

Install a fuel prevention device on your car. This ascertains that only a diesel pump nozzle can fit your tank.

It can cost you $10 – $20.

● Call a Tow Service

You should contact a tow truck company. They can bring your car to a garage.

● Hire a Mechanic

When you accidentally mixed gas with fuel, be quick to call a mechanic. Do not start your vehicle and remove your keys.

Take some assistance and push your car into a safe zone. Then contact a mechanic.

Let the mechanic bring your car to a garage. The mechanic will take away the wrong fuel and will replace it with the right one.

Make sure that the mechanic will put in enough fuel that will be suited for your trip.

The Cost of Gas in Diesel Repair

The cost of gas in diesel repair can be affordable. It can cost a few hundred dollars.

But if there is damage to your engine, it can cost you a few thousand dollars. To avoid a big expense, never start your vehicle when you have put in the wrong fuel.

Call a mechanic immediately to help you with your problem.

How to Prevent Putting Gas in Diesel Engines

How to Prevent Putting Gas in Diesel Engines

Putting gas in a diesel engine may be inevitable. One way to prevent this is to have an indicator in your diesel tank.

This will remind you of the type of fuel that you should put in. Some drivers use this as a trick.

It is not the end of the world when you have put the wrong fuel. The other things that you can do are the following:

  • Place a sticker on the cover– Place a sticker as a reminder of the fuel that you should put in your tank.
  • Have a filler neck– A filler neck can avoid you to misfuel gas.
  • Have a brightly colored cap– The colored cap is also a reminder to make you put in the right fuel.
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Tips When You Put a Gas Into a Diesel Engine

To avoid putting the wrong fuel in your vehicle, you must take a close look at the color of the handle of the pump. The handles of diesel pumps are usually green while the handles of gasoline pumps are usually black.

Know also that the nozzles of gasoline pumps are smaller than the nozzles of diesel pumps. Consider also the smell of the fuel.

If you want to have more tips, you can have the following:

  • You can only mix gas with diesel when it is winter. Do not put in a lot of gas.
  • Use an unleaded fuel can when pouring diesel into your diesel tank.
  • Know that a little amount of gas can harm your whole fuel system.
  • Know the fuel tank features of the new models of vehicles.
  • Fuels are from different materials. You have to know the differences in fuel systems.
  • When you put the wrong fuel, drain your fuel tank immediately. This will avoid you from buying a new car or a new engine.
  • Always drive slowly.
  • Before everything gets worse, fix your engine after you have put in the wrong fuel.
  • Do not start your engine after accidentally mixing gas with diesel.
  • Call a mechanic to drain your fuel tank for you.
  • Know the tank capacity of your car.
  • Know that types of diesel now are safer.
  • All of us do not know how to fix misfuelling. So, you do not have to worry about your mistake.
  • Utilize a knock sensor to fix your problem.

Dos and Don’ts

  • DO NOT ignite the fuel.
  • DO NOT start your vehicle.
  • DO call a tow truck and a mechanic.
  • DO pull your car to the side of the road.
  • DO drain your fuel tank.


How Much Gas Is Required To Injure A Diesel?

A small amount of gas, such as 10% to 15%, probably wouldn’t hurt. However, the elevated rail pumps, which work purely on diesel oil, are the section most vulnerable to harm in current common-rail motors.

What Occurs If You Get Diesel On Your Body?

Diesel may aggravate, dry, and break the skin; blisters may occur if the body is exposed for an extended period. When skin is exposed to the elements regularly, dermatitis (eczema) can form.

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