How To Rejuvenate And Recondition Old Gasoline?

Do you have old gasoline in a car that you haven’t used for a long time, and you want to know you can rejuvenate it? Or maybe you have old gasoline that you set aside for the lawnmower that you forgot about, and you want to know if you can recondition it to be reused? You’ve come to the right place, for we have researched this question, and we have the answer for you.

Follow these steps to revive your old gas:

  1. Get your tank down to a quarter full or less. If you have more than a quarter tank’s worth of gas, transfer some of the gas to another container.
  2. Fill the rest of the tank with high-octane gas.
  3. Add an octane booster to your tank.
  4. Use your car until the tank is less than a quarter tank full.
  5. Add the old gas that you removed until you get to a quarter tank full.
  6. Repeat steps 2 to 5.
  7. Once you’ve added all the old gas that you took out, refill your tank with high octane gas and octane booster at half full.
  8. Repeat step 7 two to three times.

Keep in mind that there is old gasoline, and then there’s really old gasoline that you can no longer recover. Learn how to tell if you can still recover old gasoline in the succeeding sections. Read on!

Green fuel container jerrycan isolaed, How To Rejuvenate And Recondition Old Gasoline?

How to recondition old gasoline?

Refueling Car With Gasoline Pump Nozzle

Part of reconditioning old gasoline is knowing whether the gasoline is still recoverable or not—and what to do with it if it is no longer recoverable. Determining if the old gasoline that you stored is still recoverable or not is the first step in the reconditioning process.

Read the section below to know whether the steps we provided earlier can still be used for the old gasoline that you have or not.

How to know if old gasoline can still be reconditioned?

Gasoline will start to darken as it ages. The polymerization of some gasoline components forms gum- and varnish-like substances that give it a darker color.

Gasoline with a darker color can still be reconditioned. This kind of old gasoline will still burn inside your car, but the polymerized components will no longer completely combust because of the lack of hydrocarbons. We have a section below on why there is a lack of hydrocarbons in old gasoline and why it matters.

Because these compounds will not fully combust, they will leave deposits inside the engine.

When you recondition this kind of old gasoline, never use it on a fuel-injected vehicle. This type of reconditioned gasoline is best for household use, like cleaning rust.

Gasoline that has aged further will start a separation process where you’ll notice that there are two different liquid layers. Early-stage phase separation in gasoline will have two barely distinguishable layers. Gasoline that is in the later stages of separation will have two layers that are fully distinguishable and separate.

Regardless of the stage of separation, gasoline that has started to separate will no longer be recoverable.

What other factors to consider before reconditioning old gasoline?

Not all old gasoline can be reconditioned because of how advanced the separation has gone. However, the separation rate is not the only factor you should consider before you decide to recondition your old gasoline.

Amount of old gasoline

If you have a liter or two of old gasoline lying around in a container in your garage, then you could ask yourself if it is worth the hassle of reconditioning it.

Consider the amount you paid for the old gasoline. Now consider the amount that you will pay for an octane booster that you will add to the old gasoline that you will mix with the new gasoline.

Then add to the cost the time and effort that you will spend to dilute the old gasoline with new gasoline.

Also, consider the possible engine problems that you would get from the residue of the old gasoline that we explained earlier.

Fuel injection vehicle

If you have a vehicle with an engine that uses fuel injection, then you should not use old or stale gas on your car. A reconditioned gasoline will no longer be able to run like fresh gasoline, reducing the overall performance of your car in addition to leaving residues behind.

Reconditioned gasoline is no longer safe to use with fuel injection cars because of the high potential to clog the fuel injectors of your car’s engine.

If you have a car with a fuel injector, then you’d have to look for power tools that will use your reconditioned gasoline. If you do not have power tools that use gasoline, then why recondition old gasoline at all if you cannot use it in your car?

Ethanol gasoline

Ethanol gasoline is known to absorb water vapor in the air and trap the water at the bottom of old gasoline in the process of separation. Using reconditioned gasoline that has trapped water is not something that should be used in a car regardless of the engine that it uses.

Moisture in your fuel will cause the engine to putter, hesitate, and lose much of its expected performance. The moisture can get into the engine the of your motor and cause rust to develop inside the engine.

If your old gasoline is ethanol gasoline, you can still dilute it but do not use it in your car anymore.

Why does gasoline go bad?

Gasoline gushing out from pump isolated on white background

The gasoline that we know is made of hundreds of different compounds. Some of the compounds are there to improve the octane rating of the gasoline; some improve its performance, while others help keep the fuel injectors inside your engine clean.

However, at the core of your gasoline are the carefully bonded carbon and hydrogen atoms that form energy-rich compounds called hydrocarbons. Hundreds of hydrocarbons make up gasoline’s main power source. One of the three types of hydrocarbons also determines the octane rating of gasoline.

Unfortunately, hydrocarbons evaporate as gasoline ages. The rate at which you lose hydrocarbons in your gasoline depends on the type of tank that you have in your car or the tank that you use to store fuel in your garage and the temperature.

How long can you store gasoline or diesel?

Garage corner with three red plastic fuel cans , staircase and snow plough for atv with wooden wall on background.

Gasoline in sealed tanks like the one found in modern cars can keep gasoline usable for up to 90 days. However, gasoline in unsealed tanks like the ones in older cars can only keep gasoline usable for around 30 days.

If you store your gasoline in a sealed container and in an environment that doesn’t go above 20 degrees, then your gasoline can last up to six months. The gasoline that you do not use right away loses its potency at a rate that is proportional to the heat in the environment above 20 degrees. The hotter the environment, the faster the evaporation.

Diesel is still usable without treatment for up to 12 months. Gasoline that is treated with fuel preservatives can stay fresh for up to 12 months too.

The Briggs and Stratton Press 'N Pour 5-gallon gas can is available on Amazon. Check it out through this link.

Can you dump old gasoline on the ground?

Let’s talk about what you can do when it is not feasible to rejuvenate old gasoline. Dumping gasoline on the ground is not one of the options. It is illegal in many states to dump old gasoline on the ground. It is also illegal to dump it down toilets or storm drains.

Dumping old gasoline on the ground can damage the land, cause animal death, contaminate water sources, become a fire risk, and make you incur fines.

How to properly dispose of old gasoline?

Place your gasoline inside a container that is made for gasoline or diesel. Drive to the nearest hazardous waste disposal center in your area. These centers will normally take your old gasoline and clean your container before giving it back to you.

Is it illegal to fill a fuel container at a petrol station?

Man filling plastic fuel cans at a petrol station

You can legally fill a gasoline container at a petrol station. Just make sure that your container is government-certified for transporting gasoline or diesel.

Place your container on the ground and support it while filling. Empty containers can easily tip over while filling.

Keep in mind that some petrol stations have policies regarding the size, style, and type of container. Check with them beforehand to avoid any inconvenience.

Make sure that your container is properly sealed and secured in your vehicle to prevent leaks while you’re transporting them.

What is a fuel stabilizer?

A fuel stabilizer is a fuel additive that extends the shelf life of gasoline. It has petroleum-based compounds that bind with the hydrocarbons in gasoline that slow evaporation. They also prevent stored fuel from forming resinous deposits.

It also contains antioxidants and lubricants that prevent water in the air from getting absorbed by the fuel.

The STA-BIL Storage Fuel Stabilize keeps fuel fresh for up to two years. It works for all gasoline, including all ethanol-blended fuels, and treats up to 80 gallons. Check it out on Amazon through this link.


Old iron cans for gasoline

Old fuel can be rejuvenated by diluting it with new gasoline in a mix that is one to four, then adding an octane booster. Older gasoline can be diluted in a mix of one part old gasoline and four parts new gasoline.

If you enjoyed reading this article, you might find the articles below equally enjoyable to read:

Gas Tank Overflowing When Not Full—What To Do?

What Happens If You Put Diesel In Your Gasoline Car?

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One comment

  1. What is the purpose of using high octane fuel and then adding an octane booster? A lower octane fuel is more combustible and burns hotter in any given time than a higher octane gas does. It seems to me that a hotter more complete burn would be better when trying to burn old gas. Twenty some years ago I had to get a friend’s ’68 Mustang 200 ci. 6-cyl running, not realizing that it has set up for a couple of years. The old gas candy-coated the valve stems in under ten miles and bent three push rods. I had to pull the tank and clean it and all of the fuel lines out, rebuild the carburetor, pull the head and do a backyard valve job. That was way more than I had bargained for.

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