Dumb question: Does pump gas have water in it?

[Audi Junkie]

I rarely use adds in my premium fuel. My buddy has a lo-miles Nissan and swears by Dry Gas. My offhand comment to him was that "you don't really have water in your gas unless you leave the tank empty for a long time". I did not want to get into it with him, but I mis-stated what I meant. I meant that there is not signifigant water present and Dry Gas is a waste. Is it methyl alcohol not isopropal alcohol that actually cataylizes water? So water in pump gas? Yes, no maybe?

 

[427Z06]

Some of the water in a fuel tank comes from the atmosphere. As you use the fuel up, atmospheric air is drawn in. Almost all air contains some moisture. Through daily daytime heating and nighttime cooling some of that moisture will condense out and settle to the bottom of the tank. However, as you drive, it tends to mix into the fuel (homogenize?) and get drawn in and used by the engine. Under certain weather conditions, the rate at which the water "gets" into the tank may increase, and if the ambient air is substantially below freezing, may freeze somewhere in the fuel circuit. "Dry gas" mixes with any water in the tank and lowers the freezing point so that it doesn't freeze up during it's travels in the fuel delivery circuit.

I've seen cars that sat a long time accumulate gallons of water in their tanks.

A similar process occurs in the storage tanks where we buy fuel, although some of the moisture in the ambient air may be from the tank being filled for consumer filling pumps so equipped. My understanding is the pickups on these tanks don't draw from the very bottom to avoid sucking up large quantities of water. Further, I believe most storage tanks are suppose to have water detectors to alert the proprietor when to much water accumulates in the tank or is being pumped out or something to that effect. However, some water is bound to be mixed in the fuel you purchase even if it's only trace amounts.

Whether "dry gas" is actually needed I would think depends on a variety of factors. When I lived up north I might of used it at most a dozen times, usually when the temperature was predicted to be below 0F as a precautionary measure. Whether it was actually needed or did anything useful, I don't know. Members from the Great White North may have a whole different outlook on this.

IIRC, 99.9 percent isopropyl alcohol is the best stuff to use.

[ February 15, 2005, 08:43 AM: Message edited by: 427Z06 ]

 

[moribundman]

quote:

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IIRC, 99.9 percent isopropyl alcohol is the best stuff to use.

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Lemme guess, the remaining 0.1% is water?

 

[kenw]

quote:

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Originally posted by moribundman:

quote:

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IIRC, 99.9 percent isopropyl alcohol is the best stuff to use.

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Lemme guess, the remaining 0.1% is water?

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could be water, monkey snot, old brake dust, whatever. All the label says is that 99.9% is Isopropyl alcohol.

 

[Eddie]

In the corn belt the gas is formulated using ~ 10% ethonal so dry gas and the like is not needed OR recomended.

 

[427Z06]

quote:

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Originally posted by moribundman:

quote:

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IIRC, 99.9 percent isopropyl alcohol is the best stuff to use.

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Lemme guess, the remaining 0.1% is water?

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If they follow the same process as they do to make 99% ethanol, versus the 95% ethanol my roommate used to steal from the Chemistry Dept., I'd guess it's something nasty like Benzene.

 

[Schmoe]

Water will not mix with gas, it will settle in the bottom of the tank. One way it enters is through condensation, especially with above ground tanks, they are more prone to temperature fluctuations than underground tanks. However, underground tanks can get water in them if they are leaking. New tanks must have leak detection systems built into the tank, at least, by the new EPA regulations, but getting that rule enforced has been a problem. That is why you don't see as many mom/pop gas stations anymore, it's just too dang expensive to keep up with the new regulations.
However, depending on when a tank was filled, there could be water floating around in the fuel. Tanks now have submerged filling, which means filled from the bulk delivery from the bottom up. If there was water in the tank itself, and depending on when you filled up, water could be floating around while on its' way to the bottom and you could pick up some that way. It would be a miniscule amount, but over time it could build up. Lawn mowers are notorious for this. That's way on the top end models, the gas bowl in the carb. will have a drain valve.

 

[medic]

As a rule, any water that you find in gas is due to condensation. If you put ice water into a glass in the summer, you get condensation on the outside of the glass. The same thing happens in your gas tank in in the storage tanks, except the other way around.

Winter - gas is about 55 degrees. Your car's tank is ambient temp. You get condensation. inside the tank.

Summer - the below ground storage tank is about 55 degrees. The gas is at the ambient or higher temps. Once again, warm gas into a cool tank.

I used to work at a truck stop. We checked the tanks quite often for water using a paste that would change color when it came into contact with water. There was cosistantly 2-3 inches of water at the bottom of the tanks. Once we ran out of fuel and there was still 6 inches of liquid at the bottom of the tanks, so I would say your safe.

FWIW, if I see a fuel truck parked at the tanks, I don't get gas. If they are delevering gas or have just finished, it has stirred up all of that water and what ever else may be at the bottom of the tanks. Yes, there are filters on the pumps, but who knows how old they are. And with them being able to pump the volume they do, they can't be all that restrictive.

 

[srivett]

I had been using Diesel Fuel Conditioner with every tank but now I just buy the Ultra which has it premixed by the pump. The conditioner helps against water, among other things.

My VW actually has a water seperator on the bottom of the fuel tank and another one on the bottom of the fuel filter. I've yet to see any water come out of either. Vacuum leaks after the filter are a much bigger problem.

Steve

 

[Whimsey]

quote:

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Originally posted by 427Z06:
If they follow the same process as they do to make 99% ethanol, versus the 95% ethanol my roommate used to steal from the Chemistry Dept., I'd guess it's something nasty like Benzene.

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30 years ago I worked in a lab that developed adhesives, I know that explains a lot about of my posts

. But we always had great party punches using the Pure Grain alcohol used to calibrate the instruments

. It didn't kill us so it was ok

. And no nasty hangovers either

.

Whimsey

 

[427Z06]

quote:

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Originally posted by Schmoe:
Water will not mix with gas, it will settle in the bottom of the tank...

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How then does the fat in milk stay in suspension?

Further, have a look at this: Oil and water do mix after all

quote:

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Originally posted by Schmoe:
there could be water floating around in the fuel

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Wait a minute, you said water would settle to the bottom. How could it float?

Would you settle for "gasoline and water emulsion"?

[ February 15, 2005, 12:28 PM: Message edited by: 427Z06 ]

 

[Ken2]

I know that diesel fuel contains a very small amount of water, but I don't know if it is in emulsion, or suspension, or solution. In the Fall when temperatures drop there will be more water at the bottoms of the storage tanks as the colder fuel is able to hold less water. This water in the fuel is in such small quantites that it is no problem.

I don't know if gasoline can also hold water, but it might in smaller quantities.

Dry gas is important to have available, but I wouldn't spend the money to use it often. If you do get some gas with a lot of water from a station with water in the tank, the water may plug the fuel filter. The alcohol in the Dry gas will cause the water to emulsify and pass through the engine. Gas mileage for that tank will be awful...part of each gallon is water that isn't propelling you, but you won't get stuck on the side of the road.

I carry a bottle of Dry gas in each car, but don't use it unless I feel the need.


Ken

 

[brian]

Did some 7-11's get caught with a water hose in their tanks??

-brian

 

[k1xv]

Water can get into the underground fuel tanks at a filling station in a number of ways. One is rainfall intrusion. Normally, the pick-up point for the fuel pumps dispensing gasoline is well above the bottom of the tank, and the water, being heavier than gasoline, settles to the bottom and is pumped out.

However, when a fuel delivery comes to the station, everything gets agitated. That is why knowledgable drivers do not buy gas at a station where a fuel delivery is underway.

As for the alcohol in "gasahol" attracting water, I suppose it could, but it is my understanding that this water does no harm, as the water molecules are molecularly bound to the alcohol molecules, and therefore just pass through the fuel system. It is the free water molecules not molecularly bound to the alcohol molecules that are the problem.

 

[Schmoe]

quote:

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Originally posted by 427Z06:

quote:

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Originally posted by Schmoe:
Water will not mix with gas, it will settle in the bottom of the tank...

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How then does the fat in milk stay in suspension?

Further, have a look at this: Oil and water do mix after all

quote:

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Originally posted by Schmoe:
there could be water floating around in the fuel

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Wait a minute, you said water would settle to the bottom. How could it float?

Would you settle for "gasoline and water emulsion"?

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Yes, that is what I was referring to. Your going to have water floating around in there until it settles out. The longer you wait, the more will settle.

 

[Clement]

I can tell you water does get into those tanks. About 10 yrs ago, a local Sunoco station had a problem with water in their tanks. My grandmother was one of the about 8 cars there that wouldn't start after they filled their tanks.