What to Put in Gas Tank to Ruin Engine


Last Updated on December 31, 2022 by Victor Lukasso

During the course of using a vehicle, it’s important to take note of harmful substances that could Ruin the Engine when they get into the gas tank.

This should be sounded as a warning, especially when leasing out your car for occasions, and other ceremonies as people might tend to be careless with other people’s belongings.

It’s also important to note that tampering with a borrowed vehicle’s fuel system can cause serious damage to the engine and other components.

Additionally, intentionally damaging someone else’s property is illegal and can result in criminal charges.

This article is an informative article that’ll give you a list of substances that when you put them into your gas tank, will ruin your engine.

These substances are but are not limited to water, excessive oil, bad fuel, urine, sugar, hydrogen peroxide, salt, soda, brake fluids, and bleach.

Continue reading as we explore how these substances pose a threat to your engine and how to properly maintain and care for a vehicle’s fuel system.

Things to Put in Gas Tank to Ruin Engine

Here are 10 substances you should be cautious of introducing into your gas tank in no order.

  1. Water
  2. Excessive Oil
  3. Salt
  4. Bad Fuel
  5. Brake Fluid
  6. Soda
  7. Hydrogen peroxide
  8. Bleach
  9. Urine
  10. Sugar

Now, let’s see how these things affect the engine once they get into the fuel system.

1. Water

What happens when you put water in a gas tank? This query is common among car owners who have mistakenly misplaced water for fuel while refilling their gas tanks.

This can be very disastrous since fuel and water don’t mix, this will lead to increased corrosion and will further damage the fuel injector if not managed on time.

Also, water can get into the fuel system through condensation but in small quantities which shouldn’t be a cause to worry but a deliberate act of putting water into the gas tank will damage the engine.

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The car engine might be working fine for some time but it’ll eventually stop working ad won’t respond to further inputs.

This is because of the presence of water in the fuel injector and filters which will further spread to other parts of the engine thereby making combustion impossible.

Some of the symptoms associated with water in a gas tank include;

  • Engine misfiring
  • Rough Idling
  • Illuminated check engine light
  • Unresponsive engine
  • Stalling

To resolve this, you’ll need to seek the help of a mechanic to displace the necessary parts and install a replacement.

2. Excessive Oil

Older vehicles make use of engines that allow fuel and oil to be mixed together. However, engines of modern vehicles could get damaged if excess oil is introduced into the gas tank.

If a little amount of oil gets into the gas tank; it could burn off in the process of combustion but an excess input will damage the car’s piston.

Whichever way, it’s advised to keep your gas tank free from engine oil because it’ll damage your engine slowly.

If you notice oil in your gas tank, call the attention of a mechanic for the best fixes.

3. Salt

The presence of salt in your gas tank could Ruin your engine. This is because of its corrosive ability.

Once salt gets mixed with your fuel, the salt crystals could block your fuel filters and further lead to loss of engine power.

While a small amount of salt might not be insignificant, it’ll cause little damage if they’re retained in your gas tank for a long time.

4. Bad fuel

Purchasing the wrong fuel seems to be the worst situation of them all. Gasoline is considered bad if it has a low hydrocarbon rating.

This often happens when you, fuel stations, or retailers keep fuel for a long time and start selling it without rejuvenating it.

Also, this could be a situation where the fuel gets mixed with water or other substances. In fact, any fuel that has lost its hydrogen-to-carbon bond is considered bad.

Oh well, how do you know a bad fuel? You can tell if the fuel is bad from the small and darker look.

A bad fuel will block the fuel system and cause engine failure. So, I’ll advise you not to turn on your engine if you’re lucky enough to notice it.

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You can check out our article on how to rejuvenate old gasoline and also seek the attention of a mechanic.

Also, bear in mind that not all fuel can be rejuvenated and you as the seller could be charged in court.

5. Brake fluid

Brake fluids are meant for hydraulic components such as brakes and clutches and shouldn’t find their way into the gas tank.

The presence of enough brake fluid in the fuel system can reduce the car’s overall performance and cause damage to other components.

Always ensure you’re putting the brake fluid in the right channel and always flush your brake fluid once in two years.

6. Soda

Soda in this context refers to Coca-Cola, sprite, 7up, Pepsi, and other sodium-carbonated drinks.

The presence of these soft drinks in large quantities has the ability to damage the engine. One of the notable signs is an increase in smoke output from the exhaust.

So watch out for kids or any other intruder that might want to introduce soda into your gas tank.

7. Hydrogen Peroxide

While engine peroxide helps boost your car performance, mixing hydrogen peroxide with your fuel is disastrous.

It’ll make your engine runs at higher temperatures thereby causing total damage to your motors and pumps.

8. Bleach

Bleach mixing with fuel isn’t advised because of its corrosive ability. This is possible because of the presence of chlorine in the mixture.

And the bad part of this is that it destroys the engine silently without the driver’s notice.

If you notice the presence of bleach on time then you can fix it but if your engine has accrued some damages then it’s not repairable.

9. Urine

The presence of urine in large quantities in your gas tank could also ruin your engine.

As a matter of fact, anything other than gas that gets into your gas tank would cause damage to your fuel system be it large or small.

So, the best way to avoid this is by regularly checking for strange substances in your gas tank and getting rid of them.

10. Sugar

This common household substance is capable of bringing your engine to a wreck. Introducing sugar in a large quantity will not only turn your petroleum sugary, but it’ll also clog up the fuel system.

Some of the symptoms that accompany this include stalling, low engine performance, constant fuel pump failure, and hard starting.

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Other constituents of sugar also make it hard for the engine to survive that hit. However modern cars come with a fuel system that helps prevent this.

However, I’ll advise you to seek the help of a mechanic for a proper fix.

How to Maintain a Vehicles Fuel System

Here are some guides on how you can properly maintain and care for a vehicle’s fuel system.

Use high-quality fuel

It’s always important to use a fuel with a high octane rating as recommended by the auto manufacturer.

Bad fuels can result in reduced performance and efficiency.

Replace the oil filter regularly

The fuel filter is responsible for removing contaminants from the fuel before it reaches the engine.

It is advised that you replace the fuel filter regularly to ensure the fuel system is free from dirt, debris, and other contaminants.

Keep the fuel tank full

It is generally recommended to keep the fuel tank at least half full to prevent moisture from accumulating in the tank.

Moisture can cause rust and corrosion, which can lead to problems with the fuel system.


What will damage a gas tank?

There are several factors that can damage a gas tank: corrosion, impact by external forces, adding foreign substances to the gas tank and poor maintenance will damage a gas tank.

Will bleach in a gas tank ruin an engine?

Bleach in a gas tank will ruin the engine because of the corrosive ability of the chlorine to mix with the gasoline. This can be prevented if noticed on time.

Can you put Coke in your gas tank?

Auto experts have proven that putting coke in your gas tank will damage your engine.

What’s the worst thing to pour into a gas tank?

The worst things to pour into a gas tank are water, excessive oil, bad fuel, urine, sugar, hydrogen peroxide, salt, coke, brake fluids, and bleach.

Final Words

By following the above tips, you can help ensure that your vehicle’s fuel system is working smoothly and in perfect condition.

Remember, it is never a good idea to intentionally damage your vehicle or someone else’s property. If you are experiencing problems with your fuel system, it is always best to consult a professional mechanic for assistance.