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Water in a Car’s Gas Tank: Symptoms and How to Fix

fuel tank open

Whether you like it or not, accidents do happen. For instance, you left the gas cap of your car off in a rainy day accidentally. Some people also claim that they fueled their vehicles with defective water filter and mixed the fuel with water. Then, the problem here is not about condensation because a lot of fuel tanks have sealing systems. So, they are not prone to such issue such as massive fuel storage tanks.

But, whenever there is water in gas tank, then this poses a serious issue for your car. So, it needs proper and immediate attention. But, we should still know its symptoms first to determine how to fix it. Read on to find out more.

Facts You Should Know

filling gasoline in tank

For gasoline users, you need to make sure that you set up water separator filters on your engine. Then, test them out and replace them as required. Some may have clogged due to the water separated from the ethanol. There are a lot of ways that water can gather in your car’s gas tank.

Consequently, the combustion and compression of fuel go for a total hurl. In this situation, we call this as a hydrostatic lock. It happens when your engine fails to start. Even with a small amount of water or a liter of water, it can still bring problems in your car.

Symptoms and Effects of Water in Gas Tank

Here is a list of symptoms that you should find out when the water fills your tank:


When your engine experiences this problem, then there is water in the combustion chamber. It prevents compression and combustion. So, you will know that this is a hydro lock when you cannot crank and start the engine.

Engine Stalls

The engine may start and retain the state for a while. But, the combustion becomes weaker than the usual and may cause stalling.

The Engine Won’t Start

Your engine fails to start even when you engage the ignition. However, a deficient amount of fuel will prevent the proper functioning of your engine.

Weak Economy of Fuel

When this occurs, the water will decrease the motor power. However, you will still maintain the amount of the fuel burned. But, it will cause a reduction in mileage. You also need to know that gasoline is lighter than water. When the water gets in the tank, it sinks to the bottom. That way, the tank starts to rust.

The water in your tank will make your car lose its power. Also, the water will cause the biodegradation of your fuel. In fact, it can also lead to microbial growth, which can destroy the whole fuel system and provoke filter plugging.

How to Remove Water from Your Gas Tank

Here are some steps to follow to get rid of water from the reservoir:

Replace the Contaminated Gas in the Tank

refilling fuel

It is an ideal way you can remove the entire water mixed with gasoline. You can change it with non-ethanol, high-quality gas. Fuel with ethanol may have a short lifespan. In fact, they also begin absorbing water in just a few weeks. They also take almost 50 times more water than the non-alcohol based gas.

Put High Levels of Octane Gas

If there is still gas left in your tank, you have to fill it with large amounts of octane gas. Then, you have to exhaust the gas tank quickly. It will leave your tank dry, and it will drain all of the moisture.

Apply Commercial Products

Products available on the market today may have specialized fuel methanol and additives. So, they can help in the removal of water in your tank.


You can always perform all of the procedures indicated above if your tank is full of water. However, if you are unsure if you have to remove all of the gas or just add fuel, then you should seek an expert. You can always consult a trusted mechanic, which can help you with the methods needed. You need to remember that the water in your tank may cause intensive damage in your car.

Also, it will lead to thousands of dollars due to the destruction of your engine. So, if you do not want to replace your engine or buy a new vehicle, you should find the most accurate solutions for the water in your tank.