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Does Gas Go Bad?
By ERIC PETERS, AOL AUTOS[/align][align=center]and MCF SpaceReporter[/align][align=center][/align][align=center]
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Does gasoline really go "bad" if you leave it unused for a period of time? Some people are convinced this is just another urban legend, and that people who worry about "old gas" and spend money on fuel stabilizer are wasting psychic energy as well as cash.

But in fact, gasoline can degrade over time. That can lead to a number of problems, ranging from hard starting, to rough running, to no starting at all.

Here's Why
Unlike crude oil, gasoline is a highly refined product brewed to a certain chemical composition with very specific characteristics. One characteristic of gas is volatility, a term used to describe how easily and under what conditions the gas vaporizes so it can be efficiently burned in your car's engine.

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" The most
highly volatile components in gasoline also tend to evaporate over time. " [/align][align=center][/align][align=center][/align][align=center][/align][align=center]The most highly volatile components in gasoline also tend to evaporate over time. As they do, the remaining fuel's volatility and ability to combust properly degrades. The less volatile the fuel, the less effectively it burns in your engine. The result is diminished engine performance. Your engine may still start and run, but it probably won't run as well.

The good news is, once the old gas has been consumed and the tank is topped off with fresh fuel, the problem should cure itself. Evaporation of volatile compounds can be limited by making sure the gas cap is secured tightly. For the same reason, be sure all portable gas containers are sealed tightly as well.

A More Serious Problem: Oxidation
Hydrocarbons in the gas react with oxygen to produce new compounds that eventually change the chemical composition of the fuel. This leads to gum and varnish deposits in the fuel system.

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[/align][align=center][/align][align=center][/align][align=center][/align][align=center][/align][align=center][/align][align=center]These deposits and impurities can clog up gas lines and filters, as well the small orifices in a carburetor and the even smaller orifices in a fuel injector. Removing these deposits can be expensive and your vehicle may not run at all or run very poorly until they are removed.

Water Contamination
Condensation can form inside your gas tank and lines from heat cycling. Fuels such as E85, which have a high concentration of ethanol alcohol, may be even more susceptible to water contamination, as ethanol likes to draw moisture out of the surrounding air.

Water contamination can be a problem at gas stations with light traffic due to a slightly different kind of heat cycling. The underground storage tanks experience increases and decreases in temperature. This can cause moisture to form and contaminate the fuel. When you fill up at such a station, you're pumping in the water along with the gas. Such low-traffic stations may also have other contaminants in their underground storage tanks, such as rust. They are best avoided when possible.

Water, of course, does not work too well as a fuel in an internal combustion engine. It will cause hard starting and rough running until it's purged from the system. It can also contribute to internal rusting of the gas lines and tank. The resultant scale and small particles can create a true nightmare, sometimes requiring the replacement of the gas lines and tank at considerable expense.

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[center]Posted: 2007-06-29 18:19:40


NEW YORK (CNNMoney.com) -- Using a special additive or cutting off your A/C won't really cut your gasoline consumption. But myths like these run rampant in the minds of American drivers.

Right now, the price of gasoline is again setting record highs. The average price for a gallon of regular hit $3.087 Tuesday, the third record in a row.

So before you attempt a half-baked scheme to stretch your gas dollars, here's a look at what's fact and what's fiction when it comes to fuel economy:
[/align]Nothing but gimmicks
There have been additives, special magnets and even a pill that has promised to improve a car's fuel efficiency by as much as 30 percent in some cases.

While the promise of stretching your gas dollars seems awfully lucrative, especially when they cost under $20, most of these products provide a negligible, if any, improvement in fuel efficiency, said Rik Paul, the automotive editor for the publication Consumer Reports.

Consumer Reports and the government's Environmental Protection Agency, have tested dozens of these products finding that none of them offer any significant improvement in fuel economy.

"With all the pressure car companies are under, if one of these inexpensive devices dramatically did improve fuel economy, they (automakers) would be all over it," said Paul.
[/align][/align]Windows, air conditioning - does it matter?
There's the old saw that leaving your windows rolled down creates an aerodynamic drag on your car, cutting down on your fuel efficiency. And there's the notion that the fastest way to drain your gas tank is by running your air conditioning.

Neither one is exactly spot on.

Two separate studies conducted in 2005 by Consumer Reports and the automotive Web site Edmunds.com looked at how running the A/C and opening the windows affected the fuel economy of a sedan and an SUV traveling at highway speeds.

What they found was that running the air conditioner, while it did draw power from the vehicle's engine, only reduced each vehicle's fuel economy by about 1 mile per gallon. That's not a big difference unless you drive an already gas-hungry SUV.

The Consumer Reports' study revealed that, while opening the windows does increase the aerodynamic drag on a car, it does not have a measurable effect on the vehicle's fuel economy even at highway speeds.

[/align][/align]Bottom line? Do what's most comfortable when driving on the highway since you're not going to save a whole lot of gas either way, say experts.

If you're driving around town on errands, you might save some gas rolling down the windows instead of using the A/C.

Don't wait until Wednesday
Some drivers insist the best time to buy gasoline is on a Wednesday, when pump prices have cooled from the weekend run-up when oil companies typically raise prices.
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Sales data shown is of top 20 selling cars and trucks as compiled by Autodata Corporation.
[/align][/align][/align][/align][b][size=4]That's true to a point, says Tom Kloza, chief oil analyst at the Oil Price Information Service. Gas prices tend to be higher on the weekend, but there's no ideal day of the week to purchase your gas.

Geoff Sundstrom of the motorist organization AAA notes that gas prices fluctuate from day to day and are determined by gas station owners who look at a variety of factors including wholesale gasoline prices, competi

 

Does gasoline really go "bad" if you leave it unused for a period of time? Some people are convinced this is just another urban legend, and that people who worry about "old gas" and spend money on fuel stabilizer are wasting psychic energy as well as cash.

Left long enough gas will turn to varnish. Even in your tank.

As for additives, a lot of Classic car owners I talk with swear using one such as StaBil is the best route if storing your car for a long period. And to a pointI can agree with it. BUT......... I've left the same gas in my tank for months such as storing my car(s) and whether it's luck or whatever I've never had a problem with doing this yet. So is a stabilizer really needed when leaving your car set for a long time? I really can't say?

One thing I do, do is turn my engine off say while waiting on a train. Most (99.9%) of the drivers around me do not. Must be nice to be rich?

I know doing this does save gas. Afterall, how many mpg are you getting just setting still? ZERO!

But the gas is still being used.