Normally water in your car or truck is not a bad thing – that is if it is in the radiator, windshield washer or a bottle next to the driver for him to sip on. But occasionally, and more often than we like to admit, water gets into places where it doesn't belong. The re­sults then can be expensive and dangerous.

The catalyst that brought this topic to mind was two-fold. First, today (I am writing this in mid-September during a very warm, very humid day) I got out of my air-condi­tioned vehicle and immediately my eyeglasses fogged up so badly that I could not see. The second thing was a discussion that I was hav­ ing with a friend about the fact that the almost new gas tank on his Model T was rusting. Ironically the cause is the same in both cases.

I mentioned humidity. Very briefly and simply let's discuss the term. Water, like every other material, has three forms: solid, liquid and gaseous: ice, fluid and steam. There is though, water vapor in the air. It is in a gaseous state, and generally not concentrated enough to be seen (fog and clouds are exam­ ples of visible water vapor in the air). Relative humidity is expressed as a percentage. It is de­ pendant upon temperature and the amount of moisture in the air. But for general purposes, relative humidity is the amount of gaseous water vapor in the air. As long as the air tem­perature is rather stable, the moisture remains in the air. But if something alters that relation­ ship, the water can precipitate out, When I was inside of my air-conditioned truck my eyeglasses were cooled by the A/C, plus much of the moisture in the air (humidity) was re­ moved by the air conditioner.

When I got out of the truck though, I moved my cool eyeglasses into a very warm, high-moisture content environment. The moisture in the air was immediately cooled by the glasses and turned to a liquid, fogging up my eyeglasses. When I wiped them clean, I was wiping away liquid moisture. Had I shaken my glasses, the water would have dripped off.

The same thing happened to John's Model T gas tank. When he had a quarter of a tank of gas, the tank wasn't three-quarters empty. That three-quarters was filled with air. During the day the ambient air temperature was warm; the gas tank and the air within it was warm. Warm air can hold more moisture than cold air. In the evening as the air temperature dropped, the air (both inside and outside the gas tank) compressed and 'squeezed' out excess moisture. That moisture had to go somewhere; it could not remain in a gaseous state. It 'dripped' out of the air into the gasoline.

Your gasoline contains alcohol. Alco­hol is hygroscopic*. That is it has the ability to absorb and retain water. The water mixes with the alcohol and becomes a new solution. As long as the water remains mixed with the alcohol, it will pass through the carburetor and burn in the engine.

If you live ( or lived) in a colder cli­ mate, you might remember a product known as 'Drygas®' or 'gas tank antifreeze. 'Dry­ gas® was nothing more than a percentage of alcohol. We poured it into our gas tanks dur­ing the winter to absorb water. I don't know what percent of alcohol was contained in dry gas and the container does give a percentage. The recommended dosage was a pint of dry gas per 10 gallons of gasoline. But today the refineries are putting that alcohol into our gas for us, and at a much higher concentration – about 2 gallons of alcohol in twenty gallons of gas. (That's 16 pints of concentrated – not diluted – alcohol.) Read your gas pump: con­tains 10% Ethanol means that every 10 gal­lons that you pump contains one gallon (8 pints) of alcohol. That 10% (often higher) of alcohol does a much better job of retaining the water than a little bit of dry gas. Under normal cir­cumstances, the water that 'drips' out of the air will be absorbed by, and mix with, the al­cohol and will present no problem.

When the percent of water moisture exceeds the alcohol's ability to hold it in sus­pension, it will separate out of the alcohol. This is known as phase separation. Actually, phase separation is a lot more serious than just the water dripping out. The three liquids now in the gas tank permanently separate and will not re-mix. You will end up with layers of liq­uid in your gas tank. The top layer will be gasoline, a lower octane having been deprived of the alcohol (which is an octane booster). The middle layer will be almost pure alcohol, and the lowest layer – that which contacts the bottom of your steel gas tank – is water.

Please allow me to reprint part of an ar­ticle by Joe Richardson from our February 2011 issue of Skinned Knuckles:

"One issue particularly with winter stor­age and the increased probability of fuel system condensation brought on by temperature changes is what is known as 'Phase Separation. 'This is a problem resulting in the ethanol and water actu­ally separating.from the gasoline as it sits in your tank. Once Phase Separation occurs, the ethanolcannot be re-mixed with the gasoline, and you have a layer of lower octane gasoline, a layer of ethanol and below that, water all sitting in your gas tank...here is what happens: the ethanol is hy­groscopic which means that the ethanol and water have an affinity to one another. When condensa­tion occurs, (the water) is drawn into the ethanol portion of the fuel. When the alcohol becomes sat­urated and cannot hold any more water, the ethanol and water both separate from the fuel mixture and you have trouble. The percentage of ethanol in the fuel blend determines how much water can be absorbed before the separation oc­curs. The higher the ethanol content, the more water that can be held in suspension. Reach the maximum and they both begin to separate out of the blended mixture into their own layers or phases. This can happen in as little as 90 days or less depending on conditions. One solution is to use up all the fuel and run the tank dry, but that isn't practical or even always possible. Another alternative is to keep the tank as full as possible and seal off the filler neck opening and carburetor throat with some plastic food wrap to minimize venting to the atmosphere, but you need to remem­ber to remove it before running the engine as older vehicles have vented gas caps and need to have air displace the fuel as it is used. An addi­tional solution is to use a quality fuel preservative that is specifically formulated to prevent, or rather retard or inhibit Phase Separation. Presently there are only a couple of such productson the market. One is Eastwoods Fuel Guard for Storage, # 12736. StaBil also has introduced a product, but they have advised us that retail distribution is still quite limited."

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HOW LIKELY IS IT THAT GASOLINE PHASE SEPARATION MAY OCCUR?

From February 2011 Skinned Knuckles.

As Joe described in his column, Phase Separation is a problem caused by the addition of ethanol to gasoline. Ethanol is hygroscopic; it has an affinity for water. The amount of water that the ethanol/gasoline mixture will absorb varies. The percentage of alcohol, the ambient temperatures, and the temperature changes are all factors in determining the amount of water that can be held in suspension before the ethanol, water, and gasoline separate into individual layers (phases). 

It takes as little as 18 gallons of water in a 6,000 gallon tank of 10% ethanol blend to cause Phase Separation. When the alcohol blended with the fuel reaches its saturation point, about half of the ethanol and all of the water precipitate out, leaving the gasoline with about half of its original alcohol content (and a slightly lower octane). When the blend of gasoline, ethanol and water separates, it settles into 'phases.' Water, being the heaviest, forms the bottom, totally non-combustible phase. The ethanol phase is above that, and the gasoline is the top layer. The mixture will not re-mix and cannot be made usable again. 

The water that is absorbed by the ethanol can come from water in the tank, water in the gasoline from the pump, but primarily from moisture in the air. Warm air will hold more moisture. As the air cools the water can precipitate out. Gasoline tanks in our old cars are vented; that is they are open to the atmosphere. As the gasoline (blend) in the tank warms it expands and forces air out of the tank. Then, in the evening as it cools, the gasoline contracts and sucks fresh, moisture-laden air into the tank.

(Industry and internet sources differ somewhat in the amounts of waterfall that can be held in suspension by E-10 [10% ethanol/gasoline blend]). One source advises that at 60° F, 1 gallon of E-10 will hold 3.8 teaspoons of water (about 0.50 of 1%). At 20° F the amount drops to 2.8 teaspoons of water per gallon (about 0.30 of a percent). A car sitting out-of-doors on a warm, sunny day and then cooling at night will not be able to keep the same amount of water in suspension. The result is water separating out of the mixture and settling at the bottom of your gas tank. We’ve discussed many of the handful results of a puddle of water in the bottom of your tank: fuel line corrosion, water settling into low spots in the fuel-delivery line, and too much water entering the combustion chamber of the engine.

Phase Separation is a totally different problem from the one normally experienced with gasoline that sits for prolonged periods of time in the gas tank. That problem - gum and varnish formation - is the result of the unsaturates in gasoline, known as Olefins. The Olefins are much less stable and react with oxygen to produce those gummy deposits. Leave the gum long enough and it will harden into a varnish. Neither the gum nor the varnish is soluble in most solvents - at least not solvents that you would even consider running through your en­gine. Once they form, they have to be removed by mechanical means - wire brushing, scraping or chemical boil­ ing. Gum formation can be delayed somewhat with the addition of a gasoline stabilizer. Bill Hirsch sells one such product. StaBil is probably the best known and most readily available. Eastwood markets a two-bottle system. One product stabilizes the Olefins and delays the formation of gums, and the other is specifically designed to prevent Phase Separation. Ten dollars for both products seems like a pretty good insurance policy. StaBil, too, incorporates a binder into their fuel stabilizer that will reduce phase separation, but they also (like Eastwood) have a product that is a higher concentration of the 'binder' that can be used for cars in storage for longer periods of time and especially in areas of higher ambient humidity. It's no longer easy, is it?

Phase Separation doesn't only occur during winter storage; actually the risk is greater when the days are warmer and the air can hold  more  moisture. The  cool nights  allow the moisture to leave the air (that's why, in the mornings you will often see dew on your lawn or car's surface. As the day warms, the air re-absorbs the dew). If there is a lot of empty space in the gas tank, the air in the tank will give up its moisture and we are on our way to trouble.

The reason that Phase Separation is less noticeable during the warmer summer days (and nights) is that the car(s) is driven more often during the warmer weather, the old gas is burned up – and with it the water is ab­ sorbed by the ethanol, and it is replaced with fresh, moisture-free gas.

Those of you who live (or lived) in the areas of this com1try that are subject to freezing are more than likely familiar with gas-line antifreeze. It is nothing but alcohol designed to absorb moisture and run it through the engine. E-10 gasoline does the same thing – with minimal amounts of water.

Once Phase Separation occurs, it cannot be reversed. The only real solution is to drain the gas tank and remove all of the water.

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But besides the gasoline, there is another potential trouble area that we have to watch; another area in which water can be dis­astrous: the hydraulic brake system. Brake fluid (like alcohol) is hygroscopic; it retains water. Each time that you step on the brake pedal fluid is forced out of the master cylinder to  the  wheel  cylinders.  The  fluid  from  the master cylinder is replaced by ambient air. Each time the brake pedal is released, the fluid returns to the master cylinder, absorbing a minute amount of moisture from that fresh air. Each time that the brake pedal is depressed the flow of fluid from the master cylinder creates a turbulence within the brake system. The water-laden brake fluid mixes with clean brake fluid. And similarly to the alcohol in gasoline, the brake fluid can retain only a cer­tain amount of water. Over time (perhaps three years or so) enough water can accumu­late within the brake fluid so that the satura­tion point is reached and the water precipitates out. There are now two problems. One is that the water (unlike brake fluid) is compressible. You will not achieve maximum performance from hydraulic brakes. The second problem, and probably more evident, is that the water within the brake lines can, and will, rust the steel brake lines from the inside out.

Bleeding the brakes is not enough. Normally we bleed our brakes to remove air bubbles from the lines (air is also compressi­ble; that's what gives us that soft pedal feel). We do not remove enough fluid during a brake bleed to eliminate the water. That has to be done with a complete brake system flush. A once-every-three-year brake flush is highly recommended.

As with the gasoline tank, all of the water must be removed from the system. It can only be done through a complete draining of the brake lines, master cylinder and wheel cylinders.

Originally printed in Skinned Knuckles magazine, and copyrighted by SK Publishing/Skinned Knuckles Magazine. Reprinting of any portion prohibited without written permission of SK Publishing, PO Box 6983, Huntington Beach, CA 92615.

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