Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Old gas

gas sitting in car for three years…

anyway around draining the thing…

how much and what kind of car?

Well, it’s a 2000 Chevy Cavalier. I’ll let you know how much gas when I get some juice in the thing. My dear friend has no idea. It was her son’s car before he went off to law school…

I’d want to remove as much of the old gas as possible.

If it has a plastic tank, which I think it does, add a bottle of rubbing alcohol and a few more gallons of gas and it shouldn’t be a problem. The alcohol should take care of any water and as long the gas was good 3 years ago it should be fine now.


You don’t want to add rubbing alcohol to a fuel tank because rubbing alcohol itself contains water.


I read that article and it seems the author never really says when gas goes bad just that eventually due to one or more factors something will happen to the gas that might make your car not run as well. He seems to go on about fuel stabilizer not being helpful e85 being prone to condensation. Its sounds like if you can’t dazzle them with brilliance, baffle them with B.S.

The article says 12-15 months is the best you can hope for WITH stabilizer. That would mean less time without it.

Three years is WAY too long to expect the gas to be any good, and there may already be some internal corrosion in parts of the fuel system.

The only good thing about this is that three years ago there probably wasn’t any ethanol in the gas. Ethanol absorbs water, which makes everything worse.

I’ll take back the adding alcohol before fresh gas part. But still newer cars are required to have sealed fuel systems, evaporative emissions , and their is very little in the system to corrode and I still wonder what type of fuel stabilizer the article talking about. Most are either alcohol or mineral spirits.

No way should you allow 3 year old gas to remain the system. Drain the tank, blow out the lines, and add fresh gas.
Even then you can probably expect some ragged running at first but it should clear out; knock on wood.

For what it’s worth, I’ve seen gas go completely bad (as in not even an engine cough) after only 5-6 months and I see nothing wrong with the article Tester linked.
Remove the gas cap and sniff the filler tube. If it smells like old house paint then everything in there needs to go, no doubt about it.
You’ll also likely find that if you remove a small sample of gas (tablespoon or so), dump in on the concrete and throw a match on it, that it will not instantly flare up but may take a minute to even start burning; if it burns at all.

(And if you think condensation is not a problem, consider this. I’m in the middle right now of performing a camshaft change on a near new engine for a guy. It’s a small block Ford that was rebuilt and allowed to sit for a year. He decided he wanted another camshaft profile and after tearing into it I find that some of the rocker arms and push rods have rust on them along with some rusting on the cam chain and gears.)

And to throw one more monkey wrench into the works, very often the fuel pump will seize up due to extended non-use.

I still wonder what type of fuel stabilizer the article talking about. Most are either alcohol or mineral spirits.

Neither. Alcohol is to help remove water and mineral spirits (do they really use mineral spirits?) might help remove deposits of heavy hydrocarbons.

Gasoline will break down chemically as it ages. In general the smaller molecules tend to combine to form larger molecules. Oils are larger hydrocarbons, gasoline is mostly smaller molecules and things like butane are even smaller. They are all mixes of hydrocarbons.

Over time you end up with too many large hydrocarbons and that will not work in your car engine.  The stabilizers work by inhibiting the process.  How long it takes before it will not run in the car varies with the exact gasoline mix, temperature etc.  Generally one to three years is about it with stabilizer, less without.  

 If there is not too much gasoline in the tank, you can add fresh and that will bring the average back to a usable level. 

 A second issue involves evaporation, so if the tank is not sealed the smaller hydrocarbons like butane will evaporate out, making for a larger problem.  However most modern cars have tanks that are well sealed. 

 Do Not use rubbing alcohol as it has more water in it so it likely will have more water than it can absorb already.  Did you know that if you have some absolute alcohol and mix it with an equal quantity of water you will end up with less than the two individual amounts?  1qt & 1qt = < 2 qt.