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Technical Gas question

Discussion in 'The Hokey Ass Message Board' started by gallogiro, May 5, 2014.

  1. gallogiro
    Joined: Aug 10, 2008
    Posts: 911


    I have a question guys, not sure what the answer is since google cant give me a straight answer.

    how long can gas sit in your tank before its bad if you didn't use any gas storage treatment?

    on my 65 impala the gas sat for 2 1/2 years, on my 59 it sat 1 year. tanks are about half full, if gas wasn't almost at 5 bucks a gallon here in so cal this wouldn't be an issue id just pour it out. but I know after a while gas does some chemical changes and is no good anymore. im almost sure the 65 impala gas is bad, but is one year sitting in the 59 bad already? when I look inside it LOOKS fine

    thanks in advance guys
  2. Can't say for sure, but for the same reason ($) I have already used some 4 gal. from a car that sat for 1 1/2 years with no problem. Other hambers will advise better.
  3. Smell it. If I had to guess, both are bad. Gas today sucks.
  4. birdman42
    Joined: Jan 18, 2012
    Posts: 400


    After about a month today's gas starts to break down. I would drain and start with fresh gas.

    Posted using the Full Custom H.A.M.B. App!

  5. indyjps
    Joined: Feb 21, 2007
    Posts: 4,284


    Top the tank off with fresh gas, add enough stabil to the fresh gas for the entire tank, drive it until its all gone, keep a 5 gallon can in the trunk in case you run into trouble. Refill with fresh gas, straight gas no ethanol if you can find it.
    I've done this in the past, the route I take is about a 35 mile loop going past 3 houses of friends in case the car starts to run like crap, make sure a few of them are home that day. Put some miles on the car, roll the windows down, listen to some tunes
  6. Ned Ludd
    Joined: May 15, 2009
    Posts: 4,262

    Ned Ludd

    Petrol/gasoline has always had a limited shelf life. Oxygenates have probably had no effect on that at all. E100 will draw 4% water, leaving you with E96, which is arguably a better fuel, and then stay like that for years.
  7. clem
    Joined: Dec 20, 2006
    Posts: 3,424


    Drain it and use it in your every day car if you are concerned about it. I've had it last about 3 years over here and used it in my farm motor bikes with no problems. $10 a gallon over here.
  8. The gas that is available today does not stand the test of time,the ethanol breaks down the fuel fast,,use a additive if you plan on letting the car sit a while. HRP
  9. M224SPEED
    Joined: May 12, 2010
    Posts: 171

    from Missouri

    The gasoline we are buying today , I would think shelf life is 3 - 6 months if your lucky,it might still run an engine but what type of deposits of residue has been left in the fuel sytem would be a concern as well.
  10. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    from Texas

    Some years ago my wife's Grandma died and we went to pick up her car after about 6 months. It had a 3/4 tank of gas and would not start. I went to the local gas station and bought 3 gallons of gas. Poured two in the tank and used the last to pour down the carb to start it. It started right up with the new gas and ran without problem the 100 miles back home. It seems the old gas was acceptable to run but didn't have the volatility to start the car.
  11. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,912

    dirty old man

    I don't think you're getting the same stuff in South Africa that we're getting here if you're getting much more than 6 mos. life outta pump gas witout stabilizer additive in it.
    A closed system like that found on late models with evap controls does last somewhat longer.
  12. Ned Ludd
    Joined: May 15, 2009
    Posts: 4,262

    Ned Ludd

    Roughly the same sorts of blends. That's exactly what I'm saying. Some are going to put the perishability of fuels down to recent changes in the formulations, oxygenates like ethanol in particular, but petrochemical fuels have always been perishable.

    I wish I could get hold of some E96 here; I can't, not easily. We get the same low-octane stuff you do, perhaps even worse.
  13. gallogiro
    Joined: Aug 10, 2008
    Posts: 911


    thanks guys, will drain I don't want to take my chance and shoot tar/varnish into my pistons
  14. 1oldtimer
    Joined: Aug 21, 2003
    Posts: 8,067


    California is worse, I've seen equipment at work not start after a few months (after 8 or so months the carb needs to be cleaned). We always use a stabilizer for anything that is going to sit.
  15. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,603

    Rusty O'Toole

    It is hard to say, sometimes it goes bad in months sometimes is ok after several years. If it smells like old stinky varnish DO NOT use it, it will gum up your motor. If it smells like gas ok. I will use up old gas in a lawn tractor or carburetor car but am afraid to use it in fuel injection cars. Old stinky gas must be put in cans and disposed of as hazardous waste, most places have a hazardous waste disposal day or someplace you can take it.
  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,456


    He's in California, and we only have our E10. I give it three months.
  17. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    Rusty is right, sometimes gas goes bad quickly and sometimes it is still good a couple of years later. There seems to be no rhyme or reason to it. I just bought a car that had been sitting for at least 4 years with half a tank of gas in it. I put a battery in it, shot some starting fluid down the injectors, and it started and purred like a kitten. I drove the car right after that and it ran great on that old gasoline.

    But generally, 6 months to a year gas starts to break down and turn to varnish, especially in hot weather.

  18. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547


    E-10 like gimpy said 3-6 months and if your in a stable warm enviorment with low moisture maybe longer , the more full the tank the longer also it can last because of lack of air space ( condensation ) if you get cool nights ( 40-50 degrees ) 6 months tops then I would try to burn it up ( try to pump it out of the tank and burn it up in a DD with new fuel ) as it will start to turn to acetic acid ( vinager ) and lightly corrode any aluminum or brass parts . in a old vented system it will absorb water ,

    in a post 67 car ( evap emmisions ) as long as the charcoal canister is connected it will draw out the moisture on the air the tank sucks in .

    Just to let people know stabil only works before storing it , its NOT a cleaner, its a preservative ( anti oxidizer, BHT ) and once gas starts oxidizing ( turning to varnish ) its too late to add it , to help gas thats old we tell people to use a fuel injection cleaner or 16 oz of naptha to help cut any varnish and then change the fuel filter after running that tank down .
  19. chopolds
    Joined: Oct 22, 2001
    Posts: 5,958

    from howell, nj
    1. Kustom Painters

    Agree with the others, 3- 6 months and it loses a lot of it's "light ends" the stuff that lights off first in your engine. Cold weather starts would suffer first. After 6 months, I'd be worried about varnishing starting. Don't worry about anything going into your combustion chambers, the carburetor will be the first to suffer from varnish. Most old engines can tolerate some pretty bad gas, but varnish will gum up a carb in no time (small passages, light parts prone to sticking). If in doubt, either drain it completely, or top it off with fresh fuel AND a can of carb or injector cleaner (Chevron is real good).
    I worked at Exxon Research and Engineering for 15 years.
  20. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,260


    If you can get the car started I'd burn it out if I could. Ten gallons of old gas is hard to get rid of.
  21. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    Member Emeritus

    About a moth ago I went home and with some friends, started my cars for the first time since the last week in June 2013 They all started when the battery was charged. My late models with factory electric pumps and FI started right up. My hotrods with mech pumps took some cranking to fill the carbs.

    I think each state or area has different standards for the fuel including the change over to winter mixtures. In my area, I have had no trouble with the fuel except that it seem to evaporate quicker than it once did. I might not be so fortunate in California. So take my results with a grain of salt. Your results may vary.
  22. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547


    that techron stuff they make is great stuff the Gm techs reccommend it , and I have had great luck with it

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