by B. L. Babb

Created on: May 12, 2008

Many may wonder why they should be concerned about condensation inside their gas tank. The car sits outside all of the time or in a garage why worry about it?

Take the hottest day of the year and reach under your car and touch low on the gas tank. Do not do this if you have just driven as heat from the road can warm it.

The tank will feel cool to the touch.

Take a cold beverage out of your refrigerator. Let it sit on the counter in a relatively warm room, human comfort temperature is adequate. Wait 5 10 minutes and watch the condensation form on the outside of the can or bottle.

This happens in your car's gas tank every day. Why? Driving down the road can heat the underside of your car; from friction of the tires contacting the road surface, to heat from asphalt rising under a car, and from the exhaust system heating the underside. When you park, everything cools again. If you live in a place where temperatures between daylight and darkness can greatly vary, this may also contribute to condensation in the fuel tank.

How can you prevent or greatly reduce this from occurring?

Stroll back in time for a moment. Years ago, your car ran on straight 100% gasoline.

Today, your car can run on gasoline, ethanol, or E85 (if properly equipped). If you run on 100% gasoline, you will have this condensation drain to the bottom of your gas tank and sit there. Gasoline being lighter than water will literally float on top of the water.

When you drive your car it can stir the tank around, but when parked, it will settle and the gas will float on the water.

What happens when you have ethanol or E85 blend in your tank?

Well, these fuels are water soluble meaning the water is absorbed into your gas instead of gathering in the bottom of the fuel tank in days gone by. The more water and less gas in your tank, the greater the water ratio is.

How does that water get in the tank? We are back to condensation. Unlike the beverage demonstration, the condensation does not form on the outside of your car's gas tank, it collects on the inside walls. When there is enough on the walls, it gathers and drops into the gas.

So how can you reduce the amount of condensation in your gas tank? That is easy. Relearn your car's gas gage. If you cannot afford to fill your gas tank each time you go to the station, then keep it full and treat 1/2 or 3/4 as empty and fill it when you reach these levels.

The less surface area of wall space of the inside of the tank available for condensation to form equates to less condensation.

The lower your tank level the more condensation and the more water in your fuel tank.

Do those additives work for removing water from a gas tank? I do not know if any are formulated to remove water from ethanol or E85. It would be difficult with the water suspended in the gas.

Save on repair bills by keeping your tank full or closer to full than empty. Save your money, do not buy additives to attempt to remove water from ethanol blends, it will not work.

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