Water in the gas tank is a common problem among drivers. To get there, you don't even have to do anything. For example, become a victim of vandalism or the revenge of an angry neighbor. Water always accumulates in the gas tank, regardless of the quality of the fuel at gas stations and other external factors. To get rid of it, you have to try. Fortunately, there are several ways to do this.

Signs of water in the gas tank

You can determine the presence of water in a tank of gasoline directly or indirectly. The first method is suitable for owners of cars with an injection power system. These always have a fuel pump. It is usually located directly in the fuel tank. If you remove it from there, then through the resulting hole you can see with your own eyes the water in gasoline. Additionally, the method allows you to identify traces of corrosion, debris at the bottom of the tank and other surprises.

Adviсe. Be sure to remove the terminal from the battery before climbing to the gas tank. No one is immune from a bare wire or a live contact, which, touching the "ground", will cause fuel vapors to ignite. To illuminate the inside of a dark tank, do not use matches or lighters. Our gasoline is not the best quality. But it can puff, be healthy.

If there is no direct access to the fuel pump, then to visually determine the water in the tank, you will have to dismantle it. This is a labor-intensive operation, in general, there is no special need for it. On some machines, they refine themselves and get to the pump through the bottom of the trunk, sawing a hatch in it. This, by the way, is also optional.

It is much easier to determine the presence of water in the gas tank by indirect signs:

  • white smoke from the exhaust pipe;
  • the car does not start (starting is difficult);
  • the engine does not work well;
  • the fuel tank is basically filled "at the bottom";
  • lack of prevention against water in the gas tank.

White smoke from the exhaust pipe is a mixture of exhaust gases and water vapour. Of course, this is not a 100% sign. Nevertheless. If the car does not start, or the engine runs intermittently, pulls poorly, stalls periodically, then this may indicate that gasoline enters the combustion chambers with water. As for the last two signs, there will be information on them below.

Physics and chemistry of liquids

Alcohol with petrol
Alcohol with petrol

To solve the problem in question, although not necessary, it is extremely useful and desirable to know something about water and gasoline:

  1. Water does not mix with gasoline at the molecular level. That is, it does not dissolve, such as sugar in tea.
  2. With intensive mixing, water and gasoline form an emulsion.
  3. After a short settling, the mixture is separated into the original components.
  4. Destiny of water – 1 g/cm3.
  5. The density of gasoline is 0.71 g/cm3.
  6. Accordingly, water is heavier than gasoline, and therefore tends to settle at the bottom.
  7. Water, unlike gasoline, does not burn.
Water in gasoline
Water in gasoline

This elementary knowledge will help you understand what is said next.

How does water get into the gas tank?

Filling stations can fill up with water and gasoline
Filling stations can fill up with water and gasoline

If you start with the obvious things, then the water in the gas tank appears because it was poured there. By chance. Intentionally. For the sake of experiment. Does not matter. Even at gas stations they can fill up with gasoline and water. But not to earn more. It’s just that at such gas stations they don’t follow the rules for shipping and storing fuel, as a result of which condensate accumulates in gasoline containers. Fortunately, this is extremely rare today.

A constant "source" of water in a gasoline tank is condensed moisture. It gets there from the atmosphere. Along with air. As a result of a temperature drop, water from vapor turns into a liquid, settles on the walls of the gas tank in the form of water droplets. Then it gets into gasoline. When the car is standing still, it calmly settles to the bottom. This happens after every refueling to a full tank. As a result, 50-300 ml of water can accumulate in a year.

What does this number depend on? From several factors. Water in the gas tank will accumulate the more than:

  1. Less fuel you refuel.
  2. More often you fill up with a “couple” of liters.
  3. Higher air humidity during refuelling.
  4. Stronger diurnal temperature fluctuations.

That is, most of the water in the gas tank accumulates in those who refuel the car often and a little bit. If you fill the tank full every time, then there is simply no room for moist air in it. Accordingly, there is nowhere for moisture to come from. Is that filled with gasoline.

Water in the gas tank: consequences

Gas tank corrosion
Gas tank corrosion

A few words should be said about what can happen due to water in the gas tank:

  • tank corrosion;
  • clogging of the fuel system with rust;
  • reduction of the resource of fuel filters;
  • jamming of the fuel pump in winter due to ice;
  • corrosion on nozzles, jets;
  • accumulation of condensed water in the exhaust system;
  • difficult engine start;
  • unstable work;
  • power reduction;
  • increased fuel consumption.

This is enough to understand that there is no place for water in a gas tank. It must be urgently removed from there, and in the future this moment should not be launched.

How to remove water from a gas tank

There are two ways to remove water from a gas tank:

Let 's consider both.

Physical removal

How to drain water from a gas tank
How to drain water from a gas tank

There is usually no drain plug at the bottom of the gas tank. And as we have already found out, water accumulates just at the bottom. To get rid of it, you need to provide access. To do this, most often it is enough to remove the fuel pump. It is clear that it is better to do this when there is no gasoline in the tank, or there is not enough of it left there. To get rid of water without removing the gas tank, it must be pumped out from there. This is done in exactly the same way as gasoline is drained - a tube, a vacuum, a level difference - you're done.

How to get rid of water in a gas tank
How to get rid of water in a gas tank

When all the liquid is removed from the tank, it is additionally recommended to dry it. To speed up the process, the gas tank can be slightly and carefully heated from below with a building hair dryer. Open flame sources - blowtorches, gas burners, fires - are highly discouraged.

Chemical removal

Removing water from a gas tank using chemistry
Removing water from a gas tank using chemistry

This method is simpler and safer than the one described above. To get rid of water in a gas tank using chemistry, you need:

  1. Pour into the tank a substance that can dissolve in water at the molecular level.
  2. As a result, the resulting mixture should be combustible.
  3. The density of the mixture should be closer to the density of gasoline.

If all three conditions are met, the mixture of water and our substance will mix with gasoline, and simply burn out in the engine. Naturally, the water will not go anywhere, and it will not burn. But it will not accumulate at the bottom of the gas tank, gradually evaporating and coming out in the form of white "smoke" through the exhaust system.

What is this substance? Alcohols meet all three requirements. Medical, food (from which vodka is made). The density of alcohol is almost the same as that of gasoline. It is highly soluble in water at the molecular level. The resulting mixture burns and mixes well with gasoline.

How much alcohol does it take to get rid of water in a gas tank? It all depends on how much is there. For example, to bind 50 ml of water in this way, you need 500 ml of alcohol. It is clear that it is not worth pouring such a volume into a half-empty tank. In order for the resulting mixture of water and alcohol to burn normally in the engine, gasoline is still needed. And for 50 ml of water and 500 ml of alcohol, it needs 100 times more (50 liters, a full tank).

If there is much more water in the gas tank than 50 ml, the procedure will have to be repeated several times. As a result, the water will gradually be completely removed. In addition to alcohol, other substances can be used - acetone, solvent, white spirit. There are also special fluids sold in automotive stores. But they are based on the same ordinary alcohol or solvent. If you can find such at an adequate price, then it is better to use special tools. There are high-quality liquids on the market for removing water from a gas tank, which, along with alcohols, include anti-corrosion additives and other chemicals.


Additives for removing water from the gas tank
Additives for removing water from the gas tank

In conclusion, a few simple rules, following which will help prevent the accumulation of water in the gas tank, or minimize this process:

  • Keep the fuel level in the gas tank high.
  • Use appropriate fuel additives periodically.
  • Try not to fill up at unverified gas stations.
  • Avoid gas stations with inappropriately attractive fuel prices.
  • Protect the gas tank filler neck from evil neighbors, kids and hooligans, if this is not provided for by your car initially.
A full tank is the best remedy for water in the gas tank
A full tank is the best remedy for water in the gas tank

As a rule, if you fill up to full capacity, and visit trusted gas stations without waiting for the light on the dashboard to light up, water in the gas tank can be avoided. And using a good additive just once a year, you can completely forget about the problem forever.


Ways to remove water from a gas tank



Detailed description

Physical removal of water from the fuel tank




The method is available in cases where a drain hole is provided in the bottom of the fuel tank



Pumping out

Special tools are used to pump water out of the gas tank - it is important that they "reach" to the bottom, since water is heavier than fuel, and therefore settles at the bottom

Chemical removal of water from the fuel tank




Refuel more fuel, pour medical or other ethyl alcohol into the gas tank in an amount of at least 500 milliliters (based on 50 liters of fuel), if necessary, repeat the procedure at the next refueling




Instead of alcohol, you can use acetone, solvent, white spirit - the dosage is similar




Automotive stores sell special additives designed to remove water from the gas tank - use according to the instructions on the package

Preventive measures



Fuel level

Try to keep the level of fuel in the tank as high as possible, do not operate the car with a half-empty tank for a long time




Even if there is no sign of water in the gas tank, periodically (once a year) use fuel additives to dissolve water - this will help to avoid its accumulation in the future



Verified gas stations

Try to refuel at trusted gas stations, avoid companies offering fuel at suspiciously low prices



Gas tank protection

Make sure that the fuel tank neck is closed with a key or from the passenger compartment - this will protect you from hooligans, vandals, naughty children, envious neighbors



Indirect signs of the presence of water in the gas tank

Pay attention to changes in the technical condition of the car - if there are signs of water in the fuel tank, take the measures suggested in this material as soon as possible


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