What to Put in a Gas Tank to Ruin the Engine (5 Main Substances)

Car engines are designed to function with gas in them, and no other substances. As a result, there are many things that will cause significant damage to the car engine. If there is enough of the substance in the engine, it could permanently ruin the engine and even cause the car to completely explode.

Overall, the substances that will ruin a car engine are various liquids. Even substances that can usually help keep a car running, such as brake fluid, will ruin the engine.

The following article is a detailed explanation of how various substances will ruin a car engine if they are poured into a gas tank.

Things to put in a gas tank to ruin the engine.

Substances That Will Ruin a Car Engine

The main substances that will ruin a car engine include:

  • Bleach
  • Sugar
  • Water
  • Brake Fluid
  • Hydrogen Peroxide

Most of these substances likely won’t get into your car’s gas tank. But you have to be careful about a few of them, cause they can get into your car without you even knowing.

Ruining the gas tank is the easiest way to completely ruin a car. Since a gas tank is designed to only function with gasoline in it, you can put pretty much anything aside from gas into it and destroy the tank. But the following substances are the most effective.

How to Destroy an Engine With Bleach

Bleach will ruin the gas tank in a car the most quickly. It will erode at the metal and rubber parts of the car fast, and quickly ruin the car from the inside out.

A car will still be able to run with bleach in the gas tank, but only for a short while. Bleach consists mainly of water and chlorine. Car gas tanks usually have some residue of the fuel in them. When the gas remnants come into contact with bleach, it becomes a dangerous combination.

The mix becomes extremely corrosive as it oxidizes, and a reaction referred to as “pre-burn” occurs before the mix gets to your engine. The pre-burn reaction causes the bleach to rust away at the parts in your car, which can cause them to malfunction and even cease functioning.

There are two main ways you can ruin a car engine by pouring bleach into the gas tank. The first method is to pour about a half gallon of bleach into the gas tank and drive the car around for a couple of hours. This will cause the bleach to distribute throughout your car’s engine and eat away at the parts. Eventually, the engine will be too damaged to function properly. The car will stall and refuse to start again.

The second method is to pour an entire gallon of bleach into the gas tank. The tank should have mostly bleach in it, and a small amount of gasoline. Then drive the car around for about five to ten minutes, and the engine will be completely destroyed. It takes a large amount of bleach to ruin a car engine beyond repair.

Fortunately, there is a way to prevent bleach from causing too much damage to your engine. If you think your gas tank has been filled with bleach, then you can flush the tank and pour a biofuel additive into the tank. This substance will absorb the bleach residue and clean your gas tank thoroughly. 

How to Ruin a Car Engine With Sugar

A small amount of sugar will stop the engine from functioning, but it can be cleaned. However, a large amount of sugar can completely ruin the engine and require it to be replaced. Sugar becomes sticky in a gas tank and will cause the engine to essentially get stuck.

Sugar doesn’t dissolve in gasoline like it dissolves in water or other liquids. As a result, the granules will still be floating in the tank as gas is poured in. The sugar granules will then get sucked up into the fuel lines. The fuel system will then become clogged, and the gasoline will have a difficult time getting to your engine and making the car move. Furthermore, the sugar granules can accumulate into one area of the car and cause even bigger problems.

If sugar is poured into the gas tank, it will typically accumulate in three main places:

  • The fuel pump
  • The fuel filter
  • The fuel injectors

Each of these parts are vital to ensuring the gas gets into the car’s engine, and sugar will effectively prevent that from happening. This will cause the car’s engine to stall and not start again. If about a cup or two of sugar is poured into the gas tank, it won’t cause too much damage to the car but it will need to be repaired.

However, if a large amount of sugar is poured in, then the car is pretty much a lost cause. An entire bag of sugar would have to be poured in for this to happen, so it’s unlikely, but will completely destroy your car nonetheless.

If sugar gets into your car, and it’s not enough to completely gum up your engine, then the best way to solve this problem is to clean the following parts:

  • Fuel filter
  • Fuel pipe
  • Fuel tank

A mechanic should clean out and repair each of these parts to make sure there isn’t any residue left over. The mechanic might also have to completely replace the engine if the sugar clogs are too big or have hardened. If the parts can’t be cleaned or repaired, then it’s recommended to start looking for another car.

How Water Ruins Car Engines

Water is the most likely substance to get into your gas tank without your knowledge. It can get into your gas tank if you fill up during rainy weather or condensation forms inside your gas tank.

It only takes a small amount of water to completely ruin a car’s engine, usually about a cup. The most common reason that water can get into your car’s gas tank is through condensation. Condensation can occur in the gas tank because of a quick temperature change or humid weather. Another common way that water gets into your car is if you fill your tank up while it’s raining, but only a small amount can get in this way.

The final way that water can get into your gas tank is if you fill it up with watered-down gasoline. This is more likely to cause damage to your car since a few gallons will be poured into your tank. Watered-down gasoline will make it more difficult for your car to start since water isn’t flammable and won’t get the engine going. You can tell if the gas is watered down if it comes from a run down gas station or your car is having problems starting.

Water is also heavier than gasoline, so it will sink to the bottom of the tank and be in a prime position to get sucked up into the pipes and get into the engine. The water will cause multiple parts of the engine and gas tank to rust. This can cause the engine to have difficulty starting and even to start smoking.

The best way to fix your gas tank if water has gotten into it is to flush the tank and change out the gas. Flushing the tank and changing the gas is the best way to repair your tank if a small amount of water has gotten into it, or you put watered-down gas into your car.

Flushing the gas tank requires you to drain the tank and possibly put a tank cleaning solution into it. But putting cleaner in it is optional, and recommended only if there is a large amount of water in the tank. You should also fill the tank back up with regular gas once the tank has been fully flushed.

If a large amount of water has gotten into your tank, then it’s recommended to seek professional assistance. You should also call a professional mechanic if you have tried the above method and your car is still malfunctioning.

How to Ruin the Engine With Brake Fluid

Brake fluid is a substance meant to help keep a car’s brakes functioning properly. If it’s poured into a gas tank, then it will contaminate the oxygen sensors. But this only occurs if a large amount is poured into the gas tank. Brake fluid will dilute itself in a large amount of gasoline.

Brake fluid is what helps transfer the weight from your foot on the brake pedal to the car’s brakes. It helps ensure that your engine is functioning properly, but it won’t do the same if the fluid is poured directly into your car’s gas tank. Brake fluid can cause the car’s entire fuel system to malfunction by contaminating the oxygen sensors, primarily silicon-based sensors.

The oxygen sensor is responsible for measuring the amount of exhaust gases that pass through the engine. If this gets contaminated, it will process these gases slower and might cause an exhaust gas build-up. This can then cause the engine to overheat and cease starting.

Silicon-based sensors are especially at risk because brake fluid typically has phosphorus or zinc compounds in it. If it comes into contact with a silicon oxygen sensor, then it will become contaminated more easily and cause problems with the engine more quickly.

Even a small amount of brake fluid can cause this to happen, about one cup. But if there’s only a small amount in your gas tank, then there isn’t cause for too much concern. A small amount of brake fluid will dilute by itself over time in a large amount of gasoline.

If a larger amount of brake fluid is poured into the gas tank, such as an entire bottle, then it will damage your engine significantly. If this occurs, then it’s recommended to take your car to a professional mechanic so they can flush the gas tank out and make any necessary repairs to the engine.

The only way to tell if there’s brake fluid in your gas tank is if your engine starts malfunctioning. A few of the best ways to tell if there’s an engine problem are:

  • Stalling
  • Smoking
  • The check engine light is on
  • Your engine refuses to start

If any of these issues are occurring, then it’s recommended that you bring your car to a professional mechanic as soon as possible.

Hydrogen Peroxide Also Ruins the Engine (Dangerous)

Hydrogen peroxide is the most dangerous liquid you could pour into your car’s gas tank. It will not only cause significant damage to your engine, but can cause your engine to ignite and your whole car to explode.

Pouring hydrogen peroxide into your car’s gas tank will increase the speed and power of your car for a short period of time. While this sounds interesting and possibly exciting, hydrogen peroxide is extremely dangerous when it comes into contact with gasoline and heat.

When gas and hydrogen peroxide mix, the burn rate is increased, which means the gasoline will burn and provide fuel at a faster rate than it would on its own. However, there is a certain amount of speed and power your engine can take before it gets completely destroyed.

If you put a small amount of hydrogen peroxide into your gas tank, then the worst that will happen is your engine will refuse to start. A small amount refers to about a half a cup, and you should get your car checked and fixed immediately. If you wait any longer, then the cost to repair your car could increase significantly.

If a large amount of hydrogen peroxide gets into your car’s gas tank, then you might as well start looking for a replacement car. Too much hydrogen peroxide will ultimately cause your car’s engine to ignite and explode, which is significantly more dangerous.

The best way to tell if there is hydrogen peroxide in your gas tank is by sight. Hydrogen peroxide is heavier than gasoline, so it will sink to the bottom of your tank and be very visible. It also has a slight blue color to it, so that makes it even easier to spot. If you see even a small amount of hydrogen peroxide in your tank, take the car to a mechanic as soon as possible so the tank can be flushed. 

Final Thoughts

Any of the substances described above can become very dangerous if they are poured into a gas tank. It’s important to know the effects of them and how to determine if they got into the gas tank so you can ensure your car will function properly. It’s also important to know how these substances ruin your car’s engine so you can make the safest decision and avoid any dangerous consequences.

Related: Why Is My Car Burning So Much Gas?

Scroll to Top