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Car Performance Issues: What Happens When Your Car has Water in the Gas Tank?

Pixabay.org / CC0 1.0.
Pixabay.com / CC0 1.0.

Having water in the gas tank is an issue that can cause serious damage to your car. The problem might start with mildly annoying trouble with the performance of the engine and eventually lead to damage so severe that you need a new engine and fuel injectors. This is why it’s so important for you to immediately address the issue of water in the gas tank. Below is an explanation of how the water may get in there, the obvious symptoms that you have this issue and the best methods for remedying the problem.

How Water Gets Into a Car Gas Tank

Pixabay.org / CC0 1.0.
Pixabay.com / CC0 1.0.

There are a few ways that water can get into the gas tank of your car. Rainy weather is one such way; you might have accidentally left off the cap to the tank. The rainwater will drip or fall right in. Poor quality gas is another way, which can happen if the gas station where you fill up has a bad water filter. The faulty filter means that water is pumped into your fuel tank along with the fuel.

A third way is condensation, which can naturally occur in your gas tank. Weather conditions can create 0.81 ounces of water vapor in an empty tank with the capacity to hold 200 gallons of fuel. Some of this vapor could condense into water, and more may build up over time if the water doesn’t burn out or isn’t removed in some other way.

Photo by faungg's photos on Flickr / CC BY-ND 2.0.
Photo by faungg’s photos on Flickr / CC BY-ND 2.0.

Leaving water in the fuel tank can cause thousands of dollars’ worth of damage if you don’t properly remove it right away. Along with damaging the fuel injectors over time, water that is pumped through your fuel system for a long period of time can create rust throughout the system and in the engine. The rust could eventually cause the parts in the fuel system and engine to seize.

Symptoms of Water in the Fuel Tank

Photo by Brian Snelson on Flickr / CC BY 2.0.
Photo by Brian Snelson on Flickr / CC BY 2.0.

There are several signs that indicate you have water in the gas tank. Have a professional check the fuel in your car for water if you notice any of the following signs, but still aren’t sure whether or not water is the culprit:

  • The engine might not start if there is a large amount of water in your fuel system because the water prevents fuel combustion from occurring. The water could also cause hydrostatic lock, which occurs when water gets into the cylinder above the piston, preventing the piston from completing its rotation and the engine from turning over.
  • You may feel like your car is hesitating or has trouble accelerating when you first get on the highway. If water in your gas tank is the cause, poor acceleration happens because the fuel system is pumping water into the engine rather than gas.
  • Water can also cause your car to jolt, rev or sputter when you accelerate. Sputtering or jolting can happen when the injectors suck up water instead of fuel then the car may rev when the injectors receive gas.
  • The engine could stall while you’re driving if water in your fuel system hinders the combustibility of the gas. In this case, there may be a small enough amount of water in the fuel so that the engine can still start but have too much water to where the engine can’t keep running.
  • Your mileage-to-fuel ratio can also decrease with fuel that is contaminated with water. This occurs because the engine only burns the fuel that it receives even though the gas-water mixture has the same volume.

What to Do If You Have Water in The Gas Tank

Pixabay.org / CC0 1.0.
Pixabay.com / CC0 1.0.

It’s very important that you remove water from the gas tank before it causes long-lasting damage to your fuel system or engine. The first parts to sustain damage are usually the fuel injectors, and replacing those is often expensive. The cost of repairs only increases the longer that water is present because more of the fuel system and engine becomes damaged. Avoid this by using one of the following methods to remove the water from your car fuel tank:

  • Replacing all of the gas that is in the tank is one of the easiest solutions. This might not be the cheapest method because it wastes the fuel that’s already in your tank, but it costs much less than having to repair the damage that the water will eventually cause.
  • Immediate displacement is usually the best method to remove the water. This involves siphoning out the old gas and replacing it with high octane fuel as fast as possible. However, you might want to leave your fuel tank empty for a while to dry out if there was a large amount of water present.
  • Using a fuel additive is a third, but less reliable option. Fuel driers are specifically made to remove water from gas tanks, and some examples include DFS Plus, Dri-Gas and Heet. While some fuel driers use alcohol to remove the water, others use different agents that are safer for older vehicles that have fuel system parts and seals manufactured with sensitive materials. However, this option is less reliable than the others because fuel additives don’t work when there is more water than gas in the fuel tank.

Although it’s generally safe to try using fuel additives to remove the water yourself, implementing these other solutions isn’t safe for you, your car or the environment if you don’t know exactly what you’re doing.

To ensure your safety and avoid causing unnecessary damage to your vehicle, trust a professional mechanic to take care of the job.

Even if you experience mild performance issues with your engine, such as delayed acceleration, revving or sputtering, because there’s water in your gas tank, you can regain engine performance and prevent the water from causing serious damage as long as you remove it in a timely manner.

Have you ever had to deal with water in your fuel tank? Did you remove the water yourself, or did you take your car to a professional?

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