How Water Gets into Gasoline

Most drivers are acutely aware that water and gasoline do not mix. If you put them both into the same container and shake them up, within seconds, the gasoline will rise to the top with the water sinking to the bottom. There will be a small area around the interface where gasoline, water, and air bubbles seem to intermingled.

If you let the container sit a little longer, these remnants will depart leaving a clean flat area with gasoline above and water beneath. In your car, the general rule is that gasoline burns and water does not burn. This means that too much water in your gas tank is a bad thing. The question becomes: How did that water get into the gas tank?

Water can be pumped from filling station storage tanks into your car.

In most cases, the gasoline in your car is drawn from enormous storage tanks that may be above ground or below ground where you buy your fuel. Both types of tanks are designed to keep water out and gasoline in. Sometimes this system fails because these tanks must be vented to prevent pressure explosions and to allow air inside the tank as gasoline is being pumped out.

A second filter will usually keep any water or debris from the storage tanks from entering your vehicle.

As air is drawn into the tanks, filters prevent water from entering. It is possible for the filters to fail or for them to not be in place because of poorly performed maintenance. If the filters are not in place, the water on a rainy day can easily be drawn into the storage tanks while gasoline is being pumped. The good news is that almost all water that may be in one of these tanks is removed by the filters attached to the fill nozzles at the pump.

Your car tank can develop condensation.

Water most often gets into your gas tank from condensation. When the inside temperature of your gas tank is significantly warmer than the outside air, it can develop condensation inside just like the outside of a glass of cool liquid placed in a warm environment. Normally, these amounts are small. The churning of the gasoline while driving breaks the water into very small droplets that pass through your fuel system and are vaporized within the engine cylinders.

Burning an ethanol blend of gasoline will help eliminate water.

Although water and gasoline do not mix, alcohol and water do mix. Alcohol and gasoline will also mix. Ethanol blended gasoline has the alcohol to help water become a part of your fuel. In this way, the water can be burned right along with the gasoline and remove it from your gas tank.

Gasoline additives are available to cause the water to mix with the gasoline, too.

There are quite a few excellent gasoline additives that have as at least one of their properties that they eliminate water from your fuel tank. These additives have alcohol or some similar substance that alters the water and allows it to pass relatively harmlessly through your car’s motor.