Gas Freshness

[aunut]

If I fill up today, and not use a fuel stabilizer, how long will my gas (not diesel) be ok? I've heard gas starts going bad after 30 days. I'm planning on a trip in mid October and don't want to waste $12 on a bottle of Stabil if I don't need it.

[Ranger Smith]

Buy the stabil. Run the generator. $12.00 is cheap insurance for not having to buy a carburettor and fuel pump when things get gummed up

[pjstough]

Gas should be good for six months, probably closer to a year at minimum, but if you are worried use the Stabil.

[Kirk W]

A quick search with Google will find a lot of information on aging of stored gasoline. From time to time I have done a lot of reading on the subject and the one thing that is clear is that there is no absolute time it will last and that degradation begins as soon as it is produced and the rate of degradation depends upon storage conditions. The "experts" also state that there is no set point at which the fuel is bad, but rather it slowly degrades to be of poor quality and hard on engines, long before the engine will cease to operate. From the website, Science Direct:

 

The results indicate that the use of aged fuel in automotive engines may increase fuel consumption, carbon deposits formation, carbon monoxide and hydrocarbon emissions.

All of the sources agree that exposure to air and to high temperatures will make fuels degrade much more quickly. Most also suggest that to limit air exposure you should store with a full fuel tank and as fresh as possible when stored. But they also make clear that any time period is purely speculation and has no scientific support.

 

When we bought our fulltime motorhome I knew that we would be parking for several months at a time as we chose the volunteer lifestyle so I called the Ford motorhome hotline and asked them about the proper way to store our RV when doing this. They suggested that the best way to avoid problems when parking for 30 days or more would be to fill the fuel tank completely and add a quality fuel stabilizer, then drive it for about 20 minutes before parking to insure that the mixture was completely throughout the fuel system. At that point they recommended shutting the engine down and not starting it at all until days before beginning to travel again. I can't tell you what might have happened if I had not followed those instructions because I did what they suggested at all times. I can tell you that by doing this we never once had any kind of problems from stale fuel.

 

I happen to agree with the previous posts that the price of enough stabilizer for a tank full of fuel is a very inexpensive means of avoiding any problems. To me, the cost of stabilizer is very small compared to the potential aggravation that could be caused if it does go stale.

[aunut]

Thanks. I think I will use the Stabil.

[accumack]

I would use fuel stabilizer. We have dual sport motorcycles and the first time they sat for 2 months I had to remove and clean the carburetors (wouldn't idle and ran rough) because the this crap ethanol in the gas causes the gas to break down faster.

[pjstough]

If I fill up today, and not use a fuel stabilizer, how long will my gas (not diesel) be ok? I've heard gas starts going bad after 30 days. I'm planning on a trip in mid October and don't want to waste $12 on a bottle of Stabil if I don't need it.

 

Why not just wait till October to fill up?

[pjstough]

When we first started RVing, we were weekend campers during the nice months of the year, so our RV would sit from October until April. I never worried about the gas deteriorating or moisture in the tank as I always ran the ethanol blended gasoline, and never had any problems.

[kathydavidb]

I believe that it is better to have a full tank than to have it partially full when stored. I was told that there is less chance of condensation in the tank when full. I always fill mine before parking for an extended period of time (more than 30 days) We too are snowbirds and use the MH from Oct. - May. Then it sits pretty much from May - Oct. We never had a problem with out using the stabilizer. All of my small engines I use it every fill up as you never know how long they may sit. Just my past experience.

[Biker56]

When we first started RVing, we were weekend campers during the nice months of the year, so our RV would sit from October until April. I never worried about the gas deteriorating or moisture in the tank as I always ran the ethanol blended gasoline, and never had any problems.

You should have bought some lottery tickets back then.

 

A Google search on storage of gas in vehicles below. Not one was found on leaving tank not filled or no fuel stabilizer.

That old saying. You can pay now or more later fits.

 

1. Fill the fuel tank with fresh, premium fuel. Condensation in the tank is a problem in stored vehicles, and it is widely suggested that you fill the tank completely with Premium non-alcohol fuel in order to avoid any empty space where water can accumulate. However, the gasoline can become "gummy" over time, so it is useful to add a gasoline stabilizer, which is available for lawn mowers and other seasonal yard equipment. In some areas, premium gas does not contain ethanol which is corrosive and can release water when stored for long periods. Check with gasoline company distributor.

 

2. Fill the fuel tank. Any empty space in the tank contains air, which contains water vapor, which will condense to liquid. Over time, the water can contaminate the gasoline and corrode the fuel system.

 

3.

Hydrocarbons in the gas react with oxygen to produce new compounds that eventually change the chemical composition of the fuel. This leads to gum and varnish deposits in the fuel system.

These deposits and impurities can clog up gas lines and filters, as well the small orifices in a carburetor and the even smaller orifices in a fuel injector. Removing these deposits can be expensive and your vehicle may not run at all or run very poorly until they are removed.

 

Water contamination

Condensation can form inside your gas tank and lines from heat cycling. Fuels such as E85, which have a high concentration of ethanol alcohol, may be even more susceptible to water contamination, as ethanol likes to draw moisture out of the surrounding air.

Water contamination can be a problem at gas stations with light traffic due to a slightly different kind of heat cycling. The underground storage tanks experience increases and decreases in temperature. This can cause moisture to form and contaminate the fuel. When you fill up at such a station, you're pumping in the water along with the gas. Such low-traffic stations may also have other contaminants in their underground storage tanks, such as rust. They are best avoided when possible.

Water, of course, does not work too well as a fuel in an internal combustion engine. It will cause hard starting and rough running until it's purged from the system. It can also contribute to internal rusting of the gas lines and tank. The resultant scale and small particles can create a true nightmare, sometimes requiring the replacement of the gas lines and tank at considerable expense.

You can reduce the chances of water contamination by keeping your car's gas tank as close to full as possible, especially if the vehicle is going to be left idle for an extended period.

 

How do you identify bad gas?

One way is to eyeball it. Oxidized fuel often turns darker over time and may even smell sour. You can check stored gasoline by pouring some into a clear glass container and comparing it side-by-side with known fresh gasoline. If your old sample looks noticeably darker than the fresh gas, you have strong evidence the gas has gone bad.

 

How long does it take for gas to go bad?

That depends on a number of factors. For one, it's hard to know how old the gas you just bought actually is. It may be fresh from the refinery, or it may be a month old already by the time you top off your tank. Some gasoline is mixed with better or more oxidation inhibitors than others.

It's a good rule of thumb to avoid leaving gas in your tank or a storage container for more than a coupe of months, if you can avoid it.

 

And if you can't?

If you know gas will sit in your tank or a storage container for a couple months, then it's a wise move to buy some fuel system stabilizer and mix it in with the gasoline. Do it before you put the vehicle into long-term storage or before leaving your lawn equipment fuel containers sitting for the winter. The stabilizer helps prevent oxidation, the biggie that can turn gas into garbage that gunks up your system and leads to expensive repair work.

Using fuel system stabilizer for extended storage is preferable to draining the tank and leaving the system dry. This can cause rubber hoses, gaskets and seals to dry-rot and crack, possibly leading to leaks and even a fire. In addition, a dry system can expose the insides of metal fuel lines and your gas tank to air and moisture, which can lead to or accelerate the formation of rust.

 

Fuel system stabilizer is not a cure-all and it doesn't last forever. It must be mixed with fresh gas before the vehicle is stored, not added to already old gas. It can slow down the oxidation process and keep gas fresh for as long as 12 to 15 months. If you're going to leave the vehicle parked for longer than that, you may want to drain the tank and refill with fresh fuel before returning the vehicle to service.

[pjstough]

No gamble at all. I have been using ethanol blended gasoline since the 80s and never had a problem with it.

 

This did give me a good laugh, "ethanol which is corrosive and can release water when stored for long periods". I wonder what idiot wrote that?

[Kirk W]

This did give me a good laugh, "ethanol which is corrosive and can release water when stored for long periods". I wonder what idiot wrote that?

Just some chemist, I suspect. My friend who happens to be chief chemist for a major oil refinery says much the same. And if you want, take a look at the product Dry Gas to see what it's major ingredient is and you will find it is alcohol to absorb any water in the bottom of the tank. The fact that someone has never had a problem is no guarantee that they never will. It is like insurance, which I suspect you do buy?

[pjstough]

Just some chemist, I suspect. My friend who happens to be chief chemist for a major oil refinery says much the same. And if you want, take a look at the product Dry Gas to see what it's major ingredient is and you will find it is alcohol to absorb any water in the bottom of the tank. The fact that someone has never had a problem is no guarantee that they never will. It is like insurance, which I suspect you do buy?

 

I would like to know under what conditions "ethanol can release water", and where did the water come from in the first place? I agree on Dry Gas containing alcohol, so with ethanol already mixed with gasoline, the ethanol will absorb any condensation that may be in the tank.

 

Seems we have this ethanol debate a couple of times a year. Some people quote "experts" others, like me, tell of our real world experience.

[TXiceman]

Ethanol an absorb the water. By the same token, the ethanol can evaporate and leave the water behind.

 

Since the addition of ethanol into gasoline, I know I have had more problems with small engines and the gasoline setting in the tank and carb. I started keeping Stabilt or SeaFoam in the gas can as well as in the tanks. All gasoline is drained and the engines run dry before storage for anything over 2 or 3 weeks. With this procedure, I do not have any problems with the small engines.

 

Ken

[pjstough]

Ethanol an absorb the water. By the same token, the ethanol can evaporate and leave the water behind. ...

 

Ken

 

Not to belabor this point, but my question is, under what conditions will water separate from the ethanol? Are you saying that if you have a half tank of ethanol blended with gasoline, that while in the closed tank, the ethanol with separate from the water? I dont think so, and that is the real world, and not some oil company lab.

[JRP]

The well documented real world experience from everyone other than Paul, has shown the multiple negative effects of ethanol in gas engines at percentages over 10%. Its not that the water separates' from the ethanol/alcohol, its that they both separate from the gasoline leaving a layer of alcohol & water at the bottom of your tank where the fuel pickup is located. Phase separation is a well documented, accepted, and easily demonstrated reaction. At the saturation point the ethanol and the water it attracts both drop out of suspension in the gasoline. Like any chemical reaction there are several variables involved. All along the line from manufacturing, to storage, distribution and use; the ethanol/gasoline product is subject to exposure to moisture laden air. Then it sits in your tank subjected to daily temperature swings. All of which contribute to eventually reaching the saturation point where phase separation occurs. Sitting longer just increases the odds of reaching the saturation point.

Its not the oil company labs that publicize this fact, after all they make much higher profits by mixing more of the lower cost ethanol into their gas and selling it at the same price. Its the engine manufacturers and vehicle manufacturers that are warning consumers about the many problems caused by ethanol in engines and fuel systems. Briggs & Stratton the well known small engine manufacturer now includes a section in their owners manuals - "how to avoid the damages caused by ethanol". It was primarily engine & vehicle manufacturers driving the lawsuit against the EPA E15 mandate.

[RBH]

Denigrating "some oil company lab" vs "real world" experience is the same as denigrating scientific evidence vs anecdotal evidence. Anecdotal evidence is tempting but cannot be counted on to prove any point and is therefore pretty much useless.

 

Rich

[pjstough]

"...has shown the multiple negative effects of ethanol in gas engines at percentages over 10%" A key phrase, and I wonder why are people adding water to their gas tank?

 

I agree that small engines can be a problem, as they are usually made of materials inferior that what is used in automotive systems.

 

Could you tell me how to induce "phase separation", and could you tell me why I have not see it in my 30 some years of using ethanol blended gasoline? Perhaps because it doesnt happen in the real world unless someone adds water to their gas tank?

 

Paul

[pjstough]

Denigrating "some oil company lab" vs "real world" experience is the same as denigrating scientific evidence vs anecdotal evidence. Anecdotal evidence is tempting but cannot be counted on to prove any point and is therefore pretty much useless.

 

Rich

 

You can make a lot of stuff happen in a lab, that doesnt happen in the real world.

[Kirk W]

There is an old saying. "You can lead a horse to water, but you can not make him drink."

[D&J]

This is our experience with with E10

First we use it in everything from mowers to outboards, after getting the systems clean out with E10 we have had 0 problems with it.

We leave our car from 7 months to 2 years with just a full tank of E10, just hookup the battery and it starts right up. After 2 years the mileage drops off but that's all.

We have also left our outboard with E10 for 2 years and it ran fine, not as good as fresh fuel but after 2 years even with none ethanol fuel I wouldn't have expected it to as good as fresh fuel.

Do a little experiment and put some straight gas in a glass container and ethanol in another one and let it evaporate, you will see witch one leaves that brown slug in the container.

We pull with a gas truck and just like our last 3 trucks we use nothing but E10 without any problems.

Denny

[pjstough]

This is our experience with with E10

 

First we use it in everything from mowers to outboards, after getting the systems clean out with E10 we have had 0 problems with it.

 

We leave our car from 7 months to 2 years with just a full tank of E10, just hookup the battery and it starts right up. After 2 years the mileage drops off but that's all.

 

We have also left our outboard with E10 for 2 years and it ran fine, not as good as fresh fuel but after 2 years even with none ethanol fuel I wouldn't have expected it to as good as fresh fuel.

 

Do a little experiment and put some straight gas in a glass container and ethanol in another one and let it evaporate, you will see witch one leaves that brown slug in the container.

 

We pull with a gas truck and just like our last 3 trucks we use nothing but E10 without any problems.

 

Denny

 

 

Just for the record Denny and I are not the same person. Again a real world experience, and not what someone from a lab said would happen.

[RBH]

Just for the record Denny and I are not the same person. Again a real world experience, and not what someone from a lab said would happen.

Let me ask you a question Paul. If you flipped a coin 30 times and it came up heads every time would you bet your life savings that the 31st flip will come up heads? If you decline, you don't really believe in "real world" (anecdotal) evidence. Just sayin'.

 

Rich

[D&J]

Let me ask you a question Paul. If you flipped a coin 30 times and it came up heads every time would you bet your life savings that the 31st flip will come up heads? If you decline, you don't really believe in "real world" (anecdotal) evidence. Just sayin'.Rich

Just for the record we have been leaving our car at our home base with a full tank of E10 for extended periods for ten years with no problems, same goes for the mower and boat. No flip of a coin here. Just sayin Denny

[pjstough]

Let me ask you a question Paul. If you flipped a coin 30 times and it came up heads every time would you bet your life savings that the 31st flip will come up heads? If you decline, you don't really believe in "real world" (anecdotal) evidence. Just sayin'.

 

Rich

 

It is not a flip of the coin to not have problems with ethanol blended gasoline. There are millions of cars on the road each day running ethanol blended gasoline, if what you guys say is true, there would be hundreds of them stranded on the road every day, and that just doesnt happen!

 

If ethanol blended gasoline was a bad as many on here say, you would have a huge outcry from road service companies complaining about the hundreds of service calls they make every day to help with stalled cars running ethanol blended gasoline. Again, you dont hear about it, because it just doesnt happen.