Should You be Worrying About Ethanol in Your Gas?

Ethanol Gas Prices at Pump

Why do you worry about ethanol in your UTV? Should you worry about Ethanol when you’re just trying to cruise through a trail, or tend to your property? There are a lot of good reasons to be concerned when pumping E10 gas into your $20,000 pride-and-joy, and there are also a lot of reasons why you don’t need to worry at all. E10 is still a relatively new addition to gas pumps across the US and a lot of people still have knee-jerk reactions to ethanol. We often hear people say that it makes their gas go bad or it’s bad for their engine.

Is it really that bad? Let's clear the cloud of ethanol confusion so you can make an informed decision when it’s time to gas up your UTV.

Ethanol is Booze… or at Least the Boozy Part of Booze

Ethanol is alcohol — the same alcohol that you drink — and it makes decent fuel. Without going into too much detail about the “why” of ethanol, just know that it’s the law that requires it to be in your gasoline. It is not the result of some smart gas chemists somewhere trying to make a better product.

Bottles of Drinking Alcohol
Ethanol is the same as drinking alcohol and makes decent fuel.
That makes the gas you pump “gasohol,” a mixture of petroleum-based gasoline and plant-based alcohol. When ethanol is mixed into gasoline at a ratio of 1 part ethanol to 10 parts gas like E10 gasoline, it makes little difference to your gas mileage and makes no difference to your octane rating or power output.

Sounds like a zero-sum fuel additive. Add a little bit of ethanol and nobody loses, right? Not exactly.

Beware of Phase Separation

The problem is that ethanol likes water more than it likes gasoline. Ideally ethanol will dissolve in the gas and uniformly mix with it. If water gets into your tank, the ethanol will start to dissolve into the water instead of the gas and since water and oil don’t go together, you get what is called “phase separation.” Basically, the ethanol-water mixture comes out of the gas and sinks to the bottom of the tank.

Phase separation is not good. When the ethanol sinks out of the gasoline, it lowers your octane rating significantly, but that’s the least of your worries at this point. The water can corrode your gas tank leading to rust, and you're in for a world of hurt if that water gets sucked into your engine. The only way to fix phase separation once it has occurred is by completely draining your gas tank.

How to Avoid Phase Separation

Phase separation sounds like a big problem, but it’s easy to avoid.

Bottles of Drinking Alcohol
Phase separation doesn't generally start until 90 days.
Phase separation doesn’t happen overnight. It doesn’t even happen in a week. Generally speaking, the earliest you’ll see phase separation is 90 days after you fill up with fresh gas. However, phase separation can be postponed indefinitely with proper care.

In the car you drive every day, you’re using all your fuel and refilling with fresh fuel quick enough that phase separation (let’s call it PS for short) won’t happen. With a UTV, you’re not driving as often and you might go three months or more between rides if you’re unlucky. And then it might sit all winter, too.

  • Use a Fuel Stabilizer
    What can you do to stop PS? There are a few routes you can go. The most obvious first step is to use a fuel stabilizer on your full fresh tank of gas. A fuel stabilizer like Sta-Bil, has a different kind of alcohol in it that can absorb moisture and still burn safely in your engine thus delaying PS. Sta-Bil says they’ll keep gas fresh up to 12 months with other formulations designed to keep it up to 24 months. It also keeps your gas from going stale but that has nothing to with ethanol (gasp!). We’ll cover ‘stale’ gas in a bit.

  • Keep the Gas Tank Full
    Whenever you’re storing gas, it’s important to keep a full or nearly full tank. The less air that can fit in the tank, the less condensation can occur and that means less water. On that same note, it’s important to avoid harsh temperature changes that could lead to condensation. Keep your UTV stored in a cool garage year-round if you can. If you do all that, you won’t have any troubles with E10 gasoline in your UTV.

    There are a couple other ways to stop the PS menace as well.

  • Drain Your Gas Tank For Long Term Storage
    If you plan on storing your machine over winter or longer, it’s a good idea to take an extra step or two to button everything up. Siphon the gas out of your tank and put it in your daily driver. Then use a fogging oil to coat the engine and then run the remaining fuel dry. That will get any potential ethanol out of your vehicle and keep everything well-lubricated when you go to start it up four months to a year later.

  • Ethanol-Free Fuel
    You can subvert this whole topic just by buying ethanol-free fuel… if you can find it. Sites like do their best to keep a catalog of all the gas stations in the US and Canada that offer ethanol-free fuel. While it is possible to find ethanol-free 87-octane fuel (which is what most UTVs need), you’ll likely have to pay for premium gas and lose a little power if that’s not what your UTV’s engine calls for. Personally, I’d rather keep a full tank of cheap E10 with some fuel stabilizer.

Is Ethanol Corrosive?

Yes, but at least one study shows that pure gasoline might be more corrosive than ethanol. Even if it is more corrosive than gas, there’s nothing to worry about when running E10. Modern engines like those found in all UTVs today use rubber compounds that are designed to handle a 10% ethanol to 90% gasoline fuel mixture. That means it’s not bad for your Honda Pioneer, Textron Wildcat, or Polaris RZR.

Closeup of UTV Engine
Modern engines are very corrosion resistant, so you don’t need to worry about corrosion due to ethanol.
You don’t need to worry about any corrosion due to ethanol. If you let it phase separate, you will see corrosion from the water.

Some people claim that ethanol can clear old deposits in your engine and clog your oil filter. Again, that only matters in old cars that have been running ethanol-free for years. Your UTV probably hasn’t been running ethanol-free long enough to develop deposits that would cause problems when switching to E10.

If you’re concerned about your gas turning to varnish or ‘gumming’ your engine, that has nothing to do with ethanol. It has to do with stale gas.

Does Ethanol Make Gas Go Bad Quicker?

Gas will go stale if left long enough, but it’s not ethanol's fault. It goes stale because the gasoline you buy is actually a complex set of compounds in a very specific mixture. Some of those compounds will evaporate away before the rest while others will react with the oxygen in the air to form that gummy crap you were worried about. The compounds evaporating away make the gas less volatile and give you less power. The gummy crap can clog oil filters and make your engine unhappy.

Closeup of UTV Engine
Any gas will go stale if it sits for too long, high octane or not.
Any gas can go stale, ethanol or not, high octane or not. In fact, sometimes high-octane gas sits longer at the gas station due to low demand and may be going stale before you even pump it in your engine. Anecdotal evidence shows that scenario is unlikely, though. Don’t sweat it.

Here’s the good news: keeping gas from going stale is easy. Use fuel stabilizer on a fresh tank of gas and keep your tank full when you store it. Less air means less room for evaporation and less oxidation. Easy-peasy. Careful readers will notice that those are the same measures you take to prevent phase separation. That’s two birds with one stone.

One Last Note

When it comes to UTVs, don’t use anything higher than E10. UTVs are designed for E10 or lesser concentrations of ethanol. Using higher concentrations will limit your power and make your engine harder to cold start. If you were to use E-20 or higher ethanol blends, you would see corrosion damage in your engine over time. They’re designed for E10. Use E10. Check your vehicle’s manual for gasoline recommendations specific to your UTV.

Breathe Easier

It’s easy to keep your fuel in good shape even if you don’t ride your machine every weekend, every month, or even every other month. Just remember: keep a full tank and add fuel stabilizer to fresh fuel. Do those two things, and you can put your ethanol worry to bed.