Is the gas going bad? If your RV or generator runs on gasoline, you need to know the answer to this question. Especially because the answer may surprise you…
Do you drive an RV that runs on gas? Do you use a gas generator? If so, you might be surprised at how quickly gas goes bad. Because, in fact, it goes wrong.
The life of your gas depends on a few factors and there is a way to extend it.
So I’m going to walk you through what you need to know, from why gas goes bad to how you can make your gas last longer. Even if your RV runs on diesel, you should read on as some of the tips apply to diesel as well.
We use affiliate links and may receive a small commission for purchases at no additional cost to you. Thank you for your support. You can read our full affiliate disclosure here.
The gas goes bad… Really?

Yes, gas goes bad. It has no fixed expiration date, but degrades over time. Unfortunately, the lifespan of gasoline is shorter than most people think.
Gasoline is a mixture of volatile compounds that don’t just sit around patiently waiting to be used. Over time, the compounds degrade and evaporate, thereby affecting the quality of the gasoline. The gas starts to become rubbery, which in turn affects the proper operation of the engine.
Is it ok to use old gas?
It’s not a good idea to run your RV or generator on old gas. While old gas can get you on the road, it can cause damage to your fuel system and engine.
At best, old gasoline decreases the overall performance of your RV, decreasing fuel economy. Simply put, fresh fuel means better fuel efficiency in your motorhome; bad gas means bad gas mileage.
At worst, however, bad gas can cause serious engine problems. This includes engine knocking, overspray and clogged injectors. As gasoline degrades and becomes more gummy, it can clog filters, gum up fuel lines, and damage the fuel pump and other engine components.

How fast does gas go bad?
The lifespan of gasoline depends on a few factors. However, in general gasoline goes bad in 3-6 months. This timeline is not a problem when you camp regularly. However, if you store your RV during the off-season or for extended periods of time, old gas can become a problem.
Don’t worry, I’ll tell you how to maximize the life of your gas. There are some surefire tricks that will make it last a lot longer. But first, I need to quickly explain what causes gas to go bad.
(By the way, Diesel can last up to a year before it starts to degrade. It can start to degrade as early as 6 months if not stored properly. But generally it’s good for 12 months. Then it starts to break down, just like gasoline does.)

What makes gas go bad?
The three main culprits that spoil gas are water, evaporation, and oxidation. The amount of time your gas lasts depends on how active these culprits are. Let me explain…
water
Water molecules interact with ethanol, which shortens the life of gasoline. The higher the ethanol content in fresh gasoline, the faster water vapor will degrade the gasoline.
In the United States, almost all gasoline is blended with 10% ethanol, which is a major determinant of the 3-6 month shelf life.
Evaporation
Gasoline is also highly evaporative. You may remember from a very helpful RV Lifestyle Facebook post that you shouldn’t let your gas tank run low because the gas will evaporate faster. The longer the gas is exposed to the air in the tank of your caravan or car, the more it will evaporate.
Fuel producers even explain how the gas evaporates at different temperatures…
you knew that gasoline has different gasoline mixtures in winter and summer? Winter blends have a higher RVP (Reid Vapor Pressure) and evaporate more easily, so you can start your RV or generator in cold temperatures.
Because winter gas is not as dense, so to speak, it is cheaper to produce. This is why petrol prices at the gas station are usually lower from late September to late April.

oxidation
Evaporation leads to oxidation, which means oxygen reacts with the hydrocarbons in the gasoline. These unwanted chemical reactions cause the gasoline to solidify and “gobble.”
How can you tell if the gas is bad?
The best way to tell if the gas has gone bad is by its smell and color. Of course, you don’t want to go around smelling like gasoline all day. But, a quick sniff can alert you to bad gasoline if it smells sour.
Some people describe this sour smell of rancid gas as smelling more like varnish than gasoline. You’re probably more familiar with the smell of regular gas than you think. So if it doesn’t smell good, it probably isn’t.
Another easy way to tell if the gas is bad is by its color. Old fuel is darker than fresh fuel and, as we explained, is more gummy.
How to make gas last longer
Fortunately, there are some great tricks to make your gas last longer. Keep in mind that if you’re going to stop by a gas station in a couple of months, you really don’t need to worry about these tasks. But if your RV or generator will be sitting for an extended period, you should definitely use them.
Use a fuel stabilizer

The first and most effective way to make gas last longer is to use a fuel stabilizer. A popular choice is the STA-BIL fuel stabilizer, which keeps the fuel cool up to 24 months! That’s 4 times longer than untreated gasoline!
Works on all gases mixed with ethanol. The one I linked is specially designed for storage. So you can add it to your to-do list when winterizing your RV.
It is best to pour the recommended amount of fuel stabilizer into the tank before filling it. This way, it mixes properly with the gas. Then run the engine for at least five minutes to treat the entire fuel system.
Fill your gas tank halfway

Remember that one of the most important components of gas degradation is evaporation. The more air in the gas tank, the faster it will go bad. Therefore, the best solution to combat evaporation is to refill more often.
Many people suggest that you fill with half a tank. This will optimize fuel efficiency and help extend the life of pre-filled gasoline.
This also means that it is better to store the RV tank full than half empty, especially in combination with a fuel stabilizer.
Store in optimal conditions
If you must store gasoline, you will want to store it in the most optimal conditions possible. This means storing gasoline in an airtight container in a cool, low-humidity, low-oxygen environment.
Don’t give it a chance to go bad
Another way to prevent gas from going bad is to drive more! This isn’t the cheapest tip, but it’s the funnest solution!
After all, if you do more RV, your gas won’t have a chance to go bad. I have a whole library of RV travel guides to keep you on the road. Plus, you can use the following apps to stay on the street for less…
Do you like what you see in these videos? We would appreciate it if you could subscribe to our YouTube channel (easy to do right here) and consider “hitting the bell icon” to be notified of any new videos from us. 🙂 Thank you!

Get the home study course today and worry about the road, not the repairs!
Every time you move your RV it’s like driving through a hurricane during an earthquake. Parts break and many items must be maintained, this program will show you how you can save time and money by gaining the confidence to take on most of the problems you encounter. Don’t get caught with your RV in the store! Learn how you can maintain and repair your RV at your own pace and at a time that’s most convenient for you! This course is produced by the National RV Training Academy.
The RV Rider Bike Carrier for RVs, Motorhomes and Five-Wheelers carries 2 e-bikes (up to 80 pounds each) on the back of a RV, fifth wheel or flatbed trailer. A 2-inch hitch is required for this rack. Special features include heavy-duty universal wheel supports for high load capacity. These wheel holders can fit any tire up to 5 inches wide and include a ratchet wheel strap. Locking frame grips secure bikes in place. This bike carrier is not compatible with bumper, travel trailers or bumper mounted hitch receivers.
If you want to see everything they have to offer, not just the RV Rider rack, go here and explore all the options!