Fuel stabilizer for non-ethanol gas?

I realize there are probably a hundred threads on this topic, I've been trying to search and read up on this for a good hour now, but I'm still rather lost, so so much misinformation and vague non-scientific 'it worked for me' opinions!

Trying to figure out the best way to stabilize non-ethanol gas, looks like there are two classes of products on the market: things like 'Sta-bil' which I understand a glycol based and things like SeaFoam - which I still don't understand how it actually works to stabilize fuel...

I'll share what I've researched/know, hoping some experts or petroleum chemists on here can chime in with actual knowledge!

How does fuel go bad:
  • A) Evaporation - light particles will evaporate, leaving behind the heavy sludge like consituents of fuel that will clog stuff like injectors
    • Loss of ignition vapors - light particles evaporating out also means the fewer are available to create vapors for ignition
    • SeaFoam doesn't help, maybe worse! Sta-bil seems to help a bit.
  • B) Oxidation - fuel particles break down due to interaction with oxygen. I haven't been able to understand the exact chemistry, but I'm guessing these are redox reactions that 'change' the fuel molecules, making them less ignition-prone or breaking down some of their intended chemical effects.
  • C) Water absorption - I understand that this ONLY applies if dealing with E10 (10% ethanol fuel) seeing as the ethanol is hygroscopic and will absorb water, and eventually phase separate - you will get water in bottom of tank. Water in the tank means rust, potential freezing damage, etc. Again, I'm less concerned about this seeing as I will never use E10 fuel for any storage situation!

So how do these 'stabilizers' prevent evaporation and oxidation from happening?

---- Sta-bil:
Constituents (from SDS):
1605482984073.png

  • I keep reading that Sta-bil is 'glycol based' and what it does is form a thin 'film' on top of the fuel, which seals it off from the air/moisture. Is this true? I keep reading it repeated on various forums, but haven't seen a single referenced 'source'. Based on SDS, it looks like it's 95% petroleum distillates...

---- SeaFoam:
Constituents (from SDS):
1605483141586.png

  • Ingredient no2 is isopropanol. Isopropanol chemical formula is CH3CHOHCH3. It is a colorless and highly flammable alcohol. Is isopropanol the same as isopropyl alcohol? Yes, isopropyl alcohol (or rubbing alcohol) is a common synonym for 2-propanol or isopropanol.
    • So wait, I'm guying zero-ethanol fuel and then ADDING alcohol to it to 'stabilize' it?? Isopropyl alcohol (IPA, or rubbing alcohol) is infinitely hygroscopic (hygroscopic = tending to absorb moisture from the air). What gives?
Can someone who is actually qualified in organic chemistry please chime in and explain this to me? As far as I'm concerned, until I get a real qualified explanation this stuff is sounding more and more like snake-oil!
 

WildCoast

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British Columbia, Canada
Regarding E10, then there are articles such as this that seem well references and state that E10 and ethanol actually *reduces* the risk of water in the tank, because E10 will chemically 'bind' to water instead of the water collecting in the tank: https://www.boatus.com/magazine/2011/december/ethanol.asp

"Ethanol is hydrophilic, which means ethanol holds water. With regular gasoline (E0) as well at E10, the primary cause of water collecting in tanks is condensation on tank walls. But unlike E0, which can absorb almost no moisture, E10 can hold up to half of one percent of water by volume, and the water molecules will dissolve in the fuel. The "solubilized" water will bypass the water separator and burn harmlessly through the engine."

So my deductive reasoning tells me that if you add MORE ethanol to a fuel tank, the higher concentration will mean more of the water in the tank will be 'solubilized' - and will harmlessly be burned in the engine? Hence, SeaFoam, having alcohol in it is essentially acting like a 'water absorber'?

One gallon of ethanol can absorb about 4 teaspoons of water. On the other hand, one gallon of gasoline can only absorb about 0.15% of one teaspoon of water. That sounds like a GOOD thing, no?? Water forms in fuel tanks due to condensation. Often, some additive has to be used in a fuel tank to remove/neutralize the water that can accumulate. Products such as Dry Gas or Heet are used. The active ingredient in these products is alcohol. Ethanol is alcohol. The alcohols used in Dry Gas and Heet are isopropanol or methanol. Isopropanol and methanol are less corrosive than gasoline and aromatics, but ethanol is less corrosive than isopropanol and methanol. Phase separation occurs when gasoline can no longer absorb water. Because ethanol can absorb 26 times more water than gasoline, any (imaginary) problem that can be caused by the water that accumulates in the tank is worsened if you don't have ethanol in the fuel... Am I wrong?

...

And then there are research papers like this: https://pubs.acs.org/doi/full/10.1021/acs.energyfuels.7b01682
"Ethanol–gasoline blends (EGBs) can easily absorb large amounts of water because of the presence of ethanol. Acidic compounds and ions can be dissolved in water, and these substances can have corrosive effects on metallic construction materials. With the increasing content of ethanol in fuels, the conductivity and ability of fuel to absorb water increases, and the resulting fuel is becoming more corrosive"
 
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2,216
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Ottumwa, Iowa
There is a miss conception that alcohol is just rampantly pulling moisture from any source it can find. It is not like a black hole sucking in anything it can. The storage method and containers are far more important than worrying about ethanol and stabilizers.
 
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5,465
Location
Suburban Washington DC
What vehicles do you have that this concerns you?

How does fuel go bad:
  • A) Evaporation - light particles will evaporate, leaving behind the heavy sludge like consituents of fuel that will clog stuff like injectors
    • Loss of ignition vapors - light particles evaporating out also means the fewer are available to create vapors for ignition
    • SeaFoam doesn't help, maybe worse! Sta-bil seems to help a bit.
  • B) Oxidation - fuel particles break down due to interaction with oxygen. I haven't been able to understand the exact chemistry, but I'm guessing these are redox reactions that 'change' the fuel molecules, making them less ignition-prone or breaking down some of their intended chemical effects.
  • C) Water absorption - I understand that this ONLY applies if dealing with E10 (10% ethanol fuel) seeing as the ethanol is hygroscopic and will absorb water, and eventually phase separate - you will get water in bottom of tank. Water in the tank means rust, potential freezing damage, etc. Again, I'm less concerned about this seeing as I will never use E10 fuel for any storage situation!
The above examples are not significant to modern fuel injected engines with well sealed fuel systems. I have cars in storage over 5 years with E10 in the tank and when I start them up once or twice a year, they run fine.
 

WildCoast

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Messages
8
Location
British Columbia, Canada
There is a miss conception that alcohol is just rampantly pulling moisture from any source it can find. It is not like a black hole sucking in anything it can. The storage method and containers are far more important than worrying about ethanol and stabilizers.

Totally agree. I've read this on several sites, also lots of 'experiments' on Youtube attempting to debunk just this. Moisture in a tank happens due to temperature swings and condensation - I understand that fuel filler caps aren't truly 'air tight' so air will get in, and then the moisture in said air will condense against the sides of the tank, at which point it mixes with the fuel. This is why filling the tank totally full is good practice - less empty space to fill with air, less condensation, less water in tank.
 

WildCoast

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British Columbia, Canada
What vehicles do you have that this concerns you?

Honestly, this is just curiosity/education; I hate following advice that I can't rationalize/understand. Just frustrated by the amount of vague/conflicting information on the subject and want to get the facts/science straight.

Nonetheless, to answer your question, we have a 04 Nissan Xterra, a 09 Toyota Matrix, two Honda dual-sport dirt bikes, also use fuel in my chainsaws, etc, etc. The dirt bikes get put away for the winter, and the chainsaws I usually only seem to use in the spring and fall.
 
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Central Maryland
My pickup used to sit for a month or so at a time, with 1/2 tank or so... it would run terribly when started up, hard to start, die, have to be restarted, stumble. After it ran for several minutes it was fine.

All that went away when I started using e-free fuel.

I no longer rebuild my OPE carbs on a regular basis since I store them with e-free fuel & Stabil. Used to be a regular thing.

I'm sure it's all just confirmation bias.
 
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5,465
Location
Suburban Washington DC
Honestly, this is just curiosity/education; I hate following advice that I can't rationalize/understand. Just frustrated by the amount of vague/conflicting information on the subject and want to get the facts/science straight.

Nonetheless, to answer your question, we have a 04 Nissan Xterra, a 09 Toyota Matrix, two Honda dual-sport dirt bikes, also use fuel in my chainsaws, etc, etc. The dirt bikes get put away for the winter, and the chainsaws I usually only seem to use in the spring and fall.

For the fuel injected vehicles I wouldn't worry about them unless you were going to store them more than a few years . On the others I'd just run them dry before putting them away.
 

WildCoast

Thread starter
Messages
8
Location
British Columbia, Canada
From what I can tell, in summary: E10 fuel is an issue because it might *already* be contaminated with water at the pump! Meaning that you are essentially buying gasoline with water absorbed into it - so you are introducing MORE water into your fuel tank than what would happen with 'in tank condensation'.

What does this mean: sounds like it would be BEST to a) buy ethanol-free fuel at the station and then b) ADD pure clean-ethanol or some other alcohol to it (such as isopropanol, which is in SeaFoam). This would mean you are starting with as little water as possible in the tank, and then also ensuring the fuel in the tank can absorb as much water as possible into solution (vs the water phase separating and collecting at the bottom of the tank).

Regarding a) Gas stations have water-separators and the fuel you'd be getting is actually just fuel, and not water contaminated - BECAUSE fuel can only absorb relatively tiny amounts of water (compared to E10).

It's also interesting the SeaFoam has carbon-dioxide in the SDS ingredients. I'm guessing they actually inject CO2 into the canister to displace air, so that the isopropanol in the SeaFoam doesn't absorb moisture from the air - allows for longer shelf life... just a guess.
 
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1,638
Location
South Carolina
Not all iso-octane is 100 octane. For example, nOctane is 0. Some types have a rating of 23, 39, 56, etc... the iso-octane often referenced for knock resistance, with a 100 rating, is the iso-octane 2,2,4 trimethylpentane.

Unlike ethanol, isopropyl decreases knock resistance. It's commonly found in AVgas as an anti-freezing agent. Airplane engines don't have to worry about knock at high altitude and run pig rich during take off to prevent it.

I personally look at "fuel stabilizers" as a solution looking for a problem.
 
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59
Location
Ontario Canada
Totally agree. I've read this on several sites, also lots of 'experiments' on Youtube attempting to debunk just this. Moisture in a tank happens due to temperature swings and condensation - I understand that fuel filler caps aren't truly 'air tight' so air will get in, and then the moisture in said air will condense against the sides of the tank, at which point it mixes with the fuel. This is why filling the tank totally full is good practice - less empty space to fill with air, less condensation, less water in tank.
Your description here makes a lot of sense and I assumed that the filler caps would not perfectly lock out moisture. Would problems such as this be lessened if the car was stored with a full tank? Does the surface area of moisture exposure (such as that of a tank half full) make a difference?
 
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