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I last filled the gas tank in my motorhome in September or October of 2011. I stabilized the gasoline then. I now have better than 1/2 tank (25 gallons or more) of gas. Am I better off burning what is left and then fill with fresh gas or should I top off what I have. The vehicle runs fine on what is there. What is the best approach? Thanks

If you’ll be using several tanks, then I’d fill up to help dilute any contaminants. If the next fill will be the one for storage, then I’d use up the old gas.

Either will do IF you remember to stabilize the new fuel at the time you put it in.
My 79 Chevy pickup got filled up about a year ago too. and I’ve found zero issues doing it both ways…
parking it over the winter with either full or partial tanks.

If you wonder about tank condensation or rust, park it with a full tank. ( my Cessna 172 was always topped off when parked for condensation aleviation )

If it were mine, I would fill it just to get some fresh gas in there…

Maybe put in some higher octane gas to average out the new and old? Between filling up the tank and driving around the gas should mix fairly well?

If you put stabilizer in it then it probably doesn’t matter much either way. My own inclination would be to go fill it up.

Don’t bother with higher octane. That is completely irrelevant and won’t do a thing. The minimum octane specified in the manual is the only target you need.

The octane rating will have nothing to do with it. The mix ratio is the key. Just fill up with what ever is recommended for the vehicle…and drive on.

Maybe put in some higher octane gas to average out the new and old?

High octane will not help, but then again it will not hurt. Octane is not a measure of quality or power, it is a measure of how fast or slow the fuel burns in the engine. You should choose the octane rating recommended by the car’s manufacturer. Using less can end up costing you more and using more is a wast of money.

You have more courage then I do. I have had such poor results from old gas, regardless of stabilizing, I would give it 6 months, no more. I’m with adding fresh…and pray. I would also load up on fuel system cleaner as well. Best of luck. I would under no circumstances take a long trip till I successfully went through this older gas and made sure everything was running well. They get such poor mileage…shouldn’t take long if you use it commuting to work. I would never do it again and run gas no older then 6 months…even stabilized and treated for ethanol problems.

I’ve been using gas for my mower and other power equipment that I bought in the winter of 2010. It is fine. I have also parked a car for more than a year with gas in it and it has run fine with zero problems. I have done this at least twice that I can recall. Gas can certainly go bad, but I believe that it does not go bad nearly as fast as most people think. As long as the tank or can is well sealed, and the gas and container is clean to begin with, I don’t think you’ll have any problems for at least a year. 25 gallons are going to remain usable a lot longer than someone that parks a vehicle with a couple of gallons left in the bottom of a tank full of who knows what crud.

I would probably fill it up to freshen the old gas before going on any long trips.

I’ve got one car that Iput ten miles on over the last year and it sits in the garage with a full tank. I did manage to get about 7 gallons fresh in it before that though. I guess I’d prefer to empty the tank as much as possible and start with a fresh tank again but I think either way is OK.

How long gasoline with ethanol lasts without causing problems is environment dependent. Humidity and temperature do much to exacerbate the situation. Cool conditions with very low humidity and appropriate precautions, gas can last a very long time. In very hot conditions, gas can go bad quickly…the problems often show up over time. That 's why you will get varying opinions. Carb/injector cleaner once a year does wonders.

Thank you all for your insights,
My tendency at this time is to fill the vehicle, maybe put in more stabilizer to cover what I put in and to add some fuel system cleaner. I am a fan of fuel system cleaner in my vehicles on a fairly regular basis.
Again, thanks.