How To Recondition Old Gasoline

"Old gasoline is hardly any good, just dispose of that stuff."

That's how dismissive most people are when they hear about leftover gasoline from a while back. While it's true that fuels have a shelf life and undergo chemical reactions when left unused for a long period, sometimes they can be reclaimed.    

Now, this is not something I've read on a random DIY website, but have actually tried and tested myself. Just last week, my husband discovered an old can of gasoline in the garage and was almost throwing it away. 

That's when our neighbor, Mr. Cross, intervened and told us everything about how to recondition old gasoline. So, I quickly took some notes and decided to share the information with you guys. 

Hi! I'm Stacy, your know-it-all friend, and today I'll be telling you all about the different ways you can use up old gasoline. It's pretty basic and straightforward, and I'm sure you can do it right. 

Without further ado, let's begin. 

Things You Can Do With Old Gasoline

Can Your Gas Be Reclaimed?

Now before you proceed with any of the next steps, you must first assess the condition of the fuel. Whether it can be used or not entirely depends on the quality of the gasoline (and ethanol content).   

Just like most other fuels, ethanol gasoline breaks down and eventually undergoes phase separation after some time. How quickly the disintegration process will start depends upon its exposure to air, moisture, and catalytic metals. 

You may not be able to monitor the subtle changes in real-time, but gradually the gas darkens and eventually gets stratified. Therefore, most people prefer buying small batches of gasoline, which they plan on using in the near future. 

That said, if the fuel has phase-separated, i.e., formed two distinct layers of gasoline on top and water mixed with alcohol at the bottom, it is pretty much beyond redemption. 

Can Fuel Additives Fix Phase-Separated Gas?

More often than not, some fuel additive brands claim that their product can 'fix' phase-separated gas. That's a load of hogwash and merely a marketing gimmick to push the products. Once your fuel has formed separate layers, no additive can miraculously turn it back. 

What these manufacturers essentially mean is that the additives might help in reclaiming gas that has just begun with the stratification process. However, most people fail to read between the lines and expect the formula to recondition separated gasoline. 

Remember that gasoline is a highly refined fuel comprising complex molecular bonds. As these bonds disintegrate, the octane rating drops to a point where the gas eventually fails to produce the required energy for combustion. 

Therefore, it's almost impossible to recover phase-separated gasoline and turn it back into its homogeneous state.  

How To Restore Darkened Gasoline

Before we discuss ways to recover the gas, let's explain why it darkens with time. 

Basically, this is the stage preceding phase-separation, where the old fuel starts to react internally. At this point, the heavier substances have polymerized and rapidly form varnishes and gums. 

While you can still use the fuel to run your car, these heavy substances will not combust fully. Long story short, the darkened gas will leave deposits in different parts of the engine, including the carburetors and injectors. 

Furthermore, these deposits reduce the efficiency of your car engine, which is why many vehicle owners avoid using dark gasoline. Likewise, I'd recommend not using that gasoline unless you plan on adding a highly detergent fuel additive.  

These specialized additives 'cleanse' the fuel and eliminate the deposits to avoid clogging the engine parts. This way, even if you're using darkened gasoline, it won't interfere with the functioning of your car.  

Opt For PEA Or PIB Detergents

Now that you have decided to reclaim your old can of gasoline, do not skimp on the quality of the fuel additive. Also, the best brands will mention that they include injectors or any other detergent for that matter. 

What I'm trying to say here is that you might find cheaper or newer brands who claim to use a certain 'cleaning technology' that can do wonders. However, you must steer clear of such marketing ploys and find something that actually works. Besides, it's best to be fully aware of the fuel additive composition, as you don't want to end up buying something incompatible.  

That said, you can browse through a whole range of options that are highly effective and will keep your engine from running into problems. Regardless, you must choose between PIB (polyisobutylene) detergents or PEA (polyether amine) ones, both of which are formulated for use with gasoline containing above 20% ethanol.  

Simply put, supplementing your darkened gasoline with an additive containing a high amount of PIB or PEA detergent gives you the best chance to use it optimally.

Final Words

That's all, dear friends. 

With this, I hope I could guide you in the right direction to make an informed choice. However, before you decide on the next possible course of action, here's some advice. On average, gasoline has a shelf life of 8 weeks, beyond which it starts to degrade. 

Even if you manage to reclaim your gasoline, don't expect it to be as efficient as it would have been in its ideal working condition. Also, with some cars, it's not recommended to use darkened gasoline as the mileage can take a serious hit.   

Other than that, no matter who says what, if your gas has phase-separated, there's very little you can do about it. Some 'experts' will suggest foolproof techniques to deal with it, but in no way will that be something cost-effective. 

On that note, I'd like to like to end my rant on how to rejuvenate old gasoline. So, just figure out the condition of your fuel and get to work. 

Till next time!