Saltar al contenido

▷▷ 2021 ▷ How to remove water condensation from a gas tank

4 julio, 2021

fotolia 762926 XS

by Reg Crowder

gas pumping image by Mat Hayward from

There is always a small amount of moisture in a gas tank as a result of condensation. A little water in the gas tank is nothing to worry about, but if you have too much, you will have problems. Fortunately, there are a few simple things you can do to deal with condensation when it impairs performance or prevents your car from starting. No special tools are needed, although you may need to buy a new gas cap.

Step 1

Keep your fuel tank as full as possible. That’s the cheapest and easiest thing you can do to minimize condensation in your fuel tank. Water vapor begins to condense on the top and sides of the tank’s inner surface when moist air enters the gas tank. Try to keep the tank at least half full. Three-quarters of its capacity is even better.

Step 2

When possible, use fuels mixed with ethanol.

Use fuels mixed with ethanol. Water does not mix with gasoline, but alcohol, including ethanol, can absorb water in the gas tank. Alcohol helps carry the water into the engine, where it vaporizes in the cylinders and is then expelled through the tailpipe. In some areas, various types of alcohol-blended fuels are available, including “E-85”. Everyone can help get the water out of your tank.

Step 3

Never buy gasoline while fuel is being delivered to the station.

Never fill your tank at a gas station while receiving a fuel delivery, warns Michael E. Gray, co-author of the book “Auto Upkeep: Basic Car Care, Maintenance and Repair.” Water at the bottom of underground fuel tanks does not usually cause problems for motorists. “But when a tanker ‘dumps fuel,’ the water at the bottom of the underground tanks mixes with the gas,” says Gray. If you are pumping gasoline while this is happening, there is a good chance that excessive moisture will get into the fuel tank, he says.

Step 4

Try a fuel additive.

Use a fuel additive designed to help water mix with your fuel. Almost all auto parts stores offer several types of fuel additives that can help.

Step 5

Insulate your tank if you drive in extreme conditions.

Insulate your fuel tank if you drive in extreme conditions, such as in a car over 10 years old in a tropical area where humidity is very high. Specially designed insulation blankets can be wrapped around fuel tanks to reduce the temperature difference between the inside surface of the tank and the humid air entering from outside the tank. It is rarely worth the time and expense, but in unusual conditions it might be worth considering.

Step 6

Take a close look at the opening of your gas tank.

Look closely at the opening that you insert the fuel pump nozzle when you fill the tank. Most of today’s automotive fuel systems are designed to block moist air, as well as other potentially troublesome contaminants, from entering the fuel tank. Many cars have spring-loaded flaps that pop open when the fuel pump nozzle is inserted. If this little flap is missing or not working properly, have a mechanic check and repair it.

Inspect the gas cap for wear, damage, or poor fit.

Inspect your gas cap. If the gas cap is loose, does not fit properly, or is damaged, it could be allowing moist air to enter the gas tank. You could even let rainwater drip into the tank. Buy a new replacement gas cap. Some automotive experts now say that gas caps should be inspected every 30,000 miles.

Articles will need

  • Replacement gas cap (optional)

More articles

ventos link