How to test for bad gasoline (And what to do about it)

Here’s one of life’s most uncomfortable truths: gasoline doesn’t age like wine. Unlike the latter, gasoline can only get worse with the passage of time. It’s not hard to guess we’re joking a bit here. Seriously, who’d compare gasoline to wine?  Anyway, today we’ll talk about how to recognize and test for bad gasoline.

Also, are you wondering what to do once you notice your gasoline’s gone bad? If so, the article below is just the thing you need. We’ll show you how can you prevent gasoline from going bad quickly.

Test your stored gasoline by pouring some of it into a glass cup. Sip some fresh gas in another cup. Compare the two: if the stored gasoline has turned darker in color, that probably means it has gone old. Prevent this by adding a fuel stabilizer and prolonging the shelf life of your gas up to three years.

If that’s not enough for you (and it shouldn’t be), make sure to check the rest of this text. We’ll further elaborate on the whole bad gas issue. Yes, we know how that sounds… Anyway, stick around!

Bad gas basics (FAQ)

That wasn’t the best choice of words, but let’s work with what we got. Before we continue to our main subject, you might want to take a look at some FAQs concerning bad gasoline.

Can bad gasoline do some damage to my car?

Well, that’s kind of a hard question. The answer is more leaning towards a NO, but there’s more to it. Yes, it doesn’t happen a lot. But, it’s probable. In other words: there’s a really small chance of bad gas damaging your car.

On those rare occasions, bad gas can cause damage to your internal engine components. Also, bad gas can create a gum residue that can easily cause blockages.

So, what’s the big deal, then?

Although bad gas will rarely damage your car, you should still avoid using it. Bad gasoline loses its so-called combustible properties & volatile compounds. Better said: it won’t function using its full potential.

What causes gasoline to go bad?

Gasoline has its own so-called shelf life. We use that term to describe its durability under certain conditions. For example, heat, oxygen, and humidity play crucial roles there. Anyway, if stored properly, gasoline can last from three months to three years. It all depends on the type you’re using:

• Pure gasoline lasts from three to six months.
• Ethanol-blended gas has a shorter shelf life: two to three months all in all.
• Fuel-stabilized gasoline can last you from one to three years. Under optimal conditions, that is.

What about gas in my car’s tank?

Good question. Your car’s tank isn’t what you’d call a perfect storage area. If you let your car sit for about a month, you can assume the gas inside it has gone bad. That doesn’t mean you can’t drive the vehicle. Nevertheless, avoid using the gas that’s been sitting for six or more months.

Is age the only thing that causes gas to go bad?

It isn’t. If water finds a way to your gas tank, it can contaminate it. That’s also how you end up with bad gasoline. It can be caused by condensation or a loose gas cap. Now, water can also come from a gas pump, but that’s really something you wouldn’t call usual.

Also, a cracked fuel line can cause your gas to go bad, or flakes coming from your tank.

How to notice if there’s bad gasoline in your car?

Sometimes there’s no need to test the gas that’s already in your tank. There are ways you can see or hear what’s going on while driving. Pay attention to the signs we’ll show you below. They’re most probably symptoms of your car running on bad gasoline.

Before we show you how to test for bad gasoline in storage, you might want to know these signs.

You have some difficulty starting your vehicle

This one can be summed up in a few words: engine cranks but doesn’t start. As we’ve said earlier, contaminated gas loses its power, so to speak. Now, we’ll have to make something clear. If your car won’t start, it doesn’t necessarily mean it’s because of bad gas. For example, a busted fuel pump can be an issue.

Sputtering/pinging sounds while you’re driving

This happens because gas doesn’t combust evenly when it goes bad. Be on alert for these sounds even when your car is idling. Of course, sputtering/pinging sounds your car makes aren’t only caused by bad gas. A bad fuel filter can cause the same scenario.

The “check engine” light appears while you’re on the road

Did you know that bad gas can cause your car to run lean? Now, if you have an OBD-II code reader – the code will almost certainly mean your engine’s running lean.

You’ve got trouble accelerating

If you’ve got bad gas, that will most probably cause your car to have some trouble accelerating. As we’ve already said, bad gas doesn’t burn correctly. You’ll have difficulties going up hills or other steep inclines.

Your car is stalling while you’re driving

You probably won’t experience this in your lifetime, but it’s good we mention it anyway. It’s possible your car might stall if your gas is contaminated with water or sediment. Most folks agree this is something you shouldn’t worry about, since it most likely won’t happen.

Your car’s speed changes without you pressing the pedal

Bad gasoline can cause your car to change speed without you touching the gas pedal. The most common type of this issue is your car suddenly slowing down only to speed up fast.

Burning more gas than usual?

Your engine works harder when you’re running it on bad gasoline. This can manifest in your car burning more fuel than usual. This can’t be the only symptom of your car running on bad gasoline, so keep an eye out for others.

How to test for bad gasoline kept in storage?

Now, let’s see how to test for bad gasoline held in containers.

There are differences in color between good and bad gasoline. Oxidized (bad) gas has a tendency to turn darker over time and to smell a bit sour. Pour a glass cup of both fresh and stored gasoline to see if the latter has turned darker. It will most probably mean it has gone bad.

Is there something you can do about it?

After the gas has gone bad there’s little you can do. Your best bet is to store it properly. You might want to add a fuel stabilizer to prolong your gasoline’s longevity.

Of course, you’ll need to think about what kind of containers are you using to store gas. It’s very important you only use verified ones (made out of HDPE). HDPE stands for high-density polyethylene. It’s the material most gas tanks and IBC totes are made from.

If you’re thinking of storing gas in milk jugs or something similar – forget it! Not only is it dangerous, but it will certainly shorten the shelf life of your gasoline.

How to fix bad gas in your car’s tank?

Well, you can just siphon out the bad gas out of your tank. Afterward, just pump new gas in. That’s how you fix it.

What about waterlogged gas? Can I pump the water out?

There’s a way you pump the water out of your gas tank. Firstly, if your car’s still running, there’s a good chance you won’t find much water there.

The first option you have is to use a product like Heet. It’s the easiest option out here since it’s pretty cheap (about $3). If this doesn’t take care of the issue, you’ll need to pump everything out of your gas tank. Use a fuel siphon for this.

Let’s do a quick walkthrough, shall we?

Okay, so we’re pretty close to the end section of this article. It might be the best time to do a quick recap of all the things we’ve mentioned. As we said, bad gas probably won’t damage your car, but it will cause some malfunctions. Watch out for these:

• You have some difficulty starting your vehicle. The engine cranks but doesn’t start.
• Sputtering/pinging sounds while you’re driving. Also, a bad fuel filter can cause this.
• The “check engine” light appears while you’re on the road. If you’ve got an OBD-II code reader – the code will probably mean your engine’s running lean.
• You’ve got trouble accelerating. Bad gas doesn’t burn correctly.
• Your car is stalling while you’re driving. The vehicle might stall if your gas is contaminated with water or sediment.
• Your car’s speed changes without you pressing the pedal. The car suddenly slows down only to speed up fast.
• You’re burning more gas than usual. This can’t be the only symptom of your car running on bad gasoline, so keep an eye out for other signs.

The bottom line

So, that’s about it, folks. Hopefully, now you know how to test for bad gasoline. We’ve added some nice info alongside our main topic, as it can very well come in handy. If you’re interested in finding out why your car smells like gasoline, click right here.