Rust in a Gas Tank: What REALLY Happens?! (Explained)

Rust is one of the nightmares every vehicle owner doesn’t want to see in their engines. Thus, you would see that every restoration usually seems an impossible feat whenever they see rust covering the entire vehicle. It’s also what depreciates the value of every vehicle. For this reason, you may wonder about rust when it reaches even the internals of a gas tank. So, you may ask:

If there’s rust in a gas tank, what really happens? When there’s rust in a gas tank, it does a lot of damage to the engine and the fuel system that it eventually leads to disabling the vehicle entirely. The reason is that rust in a gas tank contaminates the fuel, affects the fuel flow, and eventually causes significant damage to the entire vehicle.

Since rust is a destructive component for a vehicle, you’ll want to remove it as soon as possible. Or, you’ll want to prevent it from even reaching your gas tank. However, the question is what causes such, and how do you deal with such?

In this article, we’ll walk you through everything you need to know about rust and its possible effects on the gas tank. This way, you can understand how important it is to prevent such and deal with it if it ever happens to you.

Without further ado, let’s get into it!

Rust in a Gas Tank

What Causes Rust in the Gas Tank?

The primary cause of rust in a gas tank is the moisture that penetrates and remains inside the tank. 

The thing about gas tanks is that they are primarily made of metal, sensitive to rusting if they touch moisture from water.

Since gas tanks are always running, it can happen that water would reach them and promote moisture inside due to extreme heat. The corrosion happens quickly due to the water accompanied by the heat, causing condensation and forming rust with the metal.

At the same time, the moisture can get stuck in the gas tank for long periods, eventually reacting to the metal and produce rust.

For this reason, your gas tank can eventually lead to corrosion and get covered with rust if not maintained properly. So now, you may wonder how rust affects a gas tank.

What Happens When You Have a Rusty Gas Tank?

As soon as rust forms inside a gas tank, it’s now prone to several issues that can be significant to the overall health and performance. Here’s what happens when you have a rusty gas tank.

Poor Fuel Flow

The rust in a gas tank can expand and reach the fuel lines. As soon as it does, it can cause an inconsistent flow of fuel. As a result, it can affect your engine’s performance due to the poor distribution of fuel.

Fuel Contamination

The rust in a gas tank can mix with the fuel and cause contamination. In addition, the rust that mixes the fuel causes poor performance due to the burning of the rust and fuel mixture.

Degradation of Tank and Fuel Lines

The rust in a gas tank can also promote significant wearing down of tank and fuel lines. For this reason, it can destroy your tank if you don’t deal with the rust and let the corrosion destroy your tank.

How Do You Clean and Seal a Rusty Gas Tank?

While you can use fuel additives to prevent damages, it’s not enough to solve the rusting problem. The best way to deal with a rusty gas tank is to clean it out entirely, remove the rust, and seal the tank properly so no moisture would get inside. 

The question now is, how would you do such a thing? In general, you have four ways to clean and seal a rusty gas tank. So let’s talk about each one.

Use of Electrolysis

Electrolysis is the process of separating materials by sending an electric current through an ionic compound. A 12V battery, a chunk of ferrous metal (such as iron), and sodium carbonate are all required.

Electrolysis may be used to remove rust from small items, but minor adjustments can also be used to remove rust from a gas tank. When connecting and removing the power source, use caution and make sure the ferrous metal does not come into touch with the gas tank’s edge.

As soon as you have successfully removed the rust, you need to seal it properly to prevent it from getting rusty in the future.

Use of Abrasives                         

Using abrasive compounds to remove rust from gas tanks is a widespread practice. Any abrasive substance that can scrape away at the rust has the potential to help remove rust. Abrasives that are commonly used for this purpose include:

  • Loose nuts and bolts
  • Plain gravel
  • BBs
  • Pea or aquarium gravel

Using abrasive demands removing the gas tank and the subsequent use of a technique to guarantee that all of the gravel is removed from the tank. Most instructions call for swishing the abrasive substance about in a liquid (water or a mixture of soap and water) to remove the rust fragments.

Use of Chemicals

Chemicals can range from vinegar and baking soda, which produce a foaming chemical reaction that aids in rust removal, to muriatic acid or isopropyl alcohol. Choosing a mix of abrasives and chemicals to remove rust can also be beneficial; just make sure the products you pick are suitable and won’t harm your gas tank more.

Also, remember always to dilute the substance to avoid causing harm to your gas tank. If your gas tank includes (or might contain) brazing, you should avoid muriatic acid-based solutions since the acid can eat away at the metal before it eliminates all of the rust.

Use of Chemical Resealing Treatments

There are other rust cleaning and resealing solutions available. However, they may not be helpful for more severe rust problems. In addition, some manufacturers emphasize incompatibility with alternative fuels like ethanol.

Finding a chemical resealing procedure at your local car parts store may be simple, if not a little pricey. Unfortunately, you may need to repeat the process several times.

rust in gas tank

What Cleans Rust Out of the Gas Tank?

If you’re searching for products that can help you deal with rust issues in your gas tank, you may find the following things ideal choices:

Evapo-Rust The Original Super Safe Rust Remover

This product is an environmentally safe product that can help you remove rust in your gas tank that works within a couple of minutes. The only thing you need to do is to air dry your gas tank upon using this product since it’s water-based. 

Another good thing is that it’s non-toxic, non-corrosive, biodegradable, and safe on skin and eyes. The product also doesn’t release fumes or foul smells as it has no solvents, acids, or other harmful chemicals.

It can also work not only on vehicles parts but also for other home tools made of metal.

Here’s a link to the product.

WD-40 Specialist Rust Remover Soak

This product helps remove rust by dissolving it, restoring the old metal parts like the one in your gas tank.

It has an industrial-strength quality and extreme penetration for the rusting in your gas tank. In general, it helps remove rust without using acids or harmful chemicals.

Users usually use this product for auto restoration, which means it’s ideal for your gas tank as well.

Here’s a link to the product.

OXALIC ACID 99.6% 2 Lb.

Oxalic Acid is a popular tool to answer issues related to rusting. Thus, if you have rust problems with your gas tank, you may consider using this product. It’s an excellent product for rust removal, and even stain removal and other similar issues.

Here’s a link to the product.

POR-15 40704 Rust Remover

Like the former products, this one is also designed to help users remove rust with ease. The great thing about this product is that it’s completely safe since it won’t affect plastic, PVC, or even paints.

Since it’s a non-corrosive product, you can use it safely for your gas tank to remove the rust build-up inside of it.

Here’s a link to the product.

JENOLITE Original Rust Remover 

This product clears up rust in a gas tank by clinging into it and penetrating deep into the affected areas of the rust. Moreover, it’s not something that can damage the metals in the gas tank while removing the rust.

One good thing about this product is that it works quickly, and you can see the rust disappearing. 

Here’s a link to the product.

POR-15 49216 Fuel Tank Sealer 

As soon as you remove the rust, you’ll need a product that can help seal your tank, so it prevents moisture from entering and causing rust again.

This sealant can seal pinholes and seams while being resistant to fuel additives, alcohols, and other chemicals. In short, it can withstand and protect your gas tank for a long time.

Here’s a link to the product.


In a nutshell, rust is a true nightmare for every gas tank. Rust in a gas tank does so much harm to the engine and fuel system that it finally renders the car completely useless. Rust in a gas tank pollutes the gasoline, disrupts the fuel flow, and finally damages the entire vehicle.

For this reason, you need to deal with the rust as soon as possible. The only way to do it is to take out the tank, clean and remove the rust entirely, and seal the tank thoroughly. You may do so to avoid rust build-up in the future.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more