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How to Get Water Out of Diesel Fuel

While you need to drink water to survive, water in your diesel fuel can be the death of your vehicle. Diesel fuel contaminated with water is not something you want to ignore, and you should rid your fuel system of contaminated diesel fuel as soon as possible.

Failure to do so may result in a hefty repair bill. But what do you need to do to get water out of diesel fuel? Let’s take a look!

What Happens When Water Gets in Diesel Fuel?

Diesel engines require specific chemistry for diesel fuel to operate efficiently. Combining two liquids changes the chemistry of both fluids. A change to the chemical makeup of the fuel could cause a decrease in engine performance and potentially damage your vehicle.

If enough water gets into your fuel system, it can cause a host of issues and shut down your entire vehicle. Over time clogs may develop in your fuel filters, and your fuel injectors might close up and restrict fuel flow. Water can also cause the steel and iron components in your fuel system and engine to rust.

Water in your vehicle’s diesel fuel can cause massive damage if you don’t address it immediately. The longer you put off attending to the issue, the larger your repair bill could become.

Does Water Go to the Bottom of Diesel?

Diesel and water, much like oil and water, don’t mix. When you mix diesel and water, diesel will float on top of the water. Water is a heavier liquid and will settle at the bottom of your fuel tank.

The density of the water in your tank is why you must use a siphoning hose capable of reaching the bottom. Failure to do so will make it impossible to get all the water out of your fuel tank. You need to completely drain your fuel tank to ensure you remove every trace of water.

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Is There an Additive to Remove Water From Diesel Fuel?

There are methanol-based fuel additives that can help dilute the water-fuel mixture. We only recommend using this method when dealing with minimal water in your diesel fuel. It’s not as effective against large amounts of water. 

Many diesel owners will regularly use diesel fuel supplements to minimize water in the fuel system and reduce potential issues. They’ll often change between different types of supplements based on the season.

If you happen to live in an area prone to cooler temperatures, make sure to use an additive in the winter months. Temperature changes can cause condensation to develop inside your fuel tank. This condensation can build up over time and slowly cause issues for you and your vehicle.

Water and diesel being poured.
Like oil and water, diesel and water do not mix!

Does Diesel 911 Remove Water?

One of the benefits of using Diesel 911 is removing water from your vehicle’s fuel system. Diesel 911 helps extend the life of your fuel filters, fuel injection pumps, and fuel injectors.

It also enables you to get maximum performance and reliability from your vehicle.

How to Get Water Out of Diesel Fuel

We recommend having an automotive professional perform this task, and always read your vehicle’s owner’s manual before working on your own vehicle.

To get water out of your diesel fuel, you need to drain or pump as much water out of your fuel tank as possible. Remember to use a siphon hose long enough to reach the bottom of your tank. Add the proper amount of Diesel 911 (or your preferred diesel additive) to your fuel tank.

For Diesel 911, the appropriate mixture for removing water as recommended by Diesel 911 is 16 ounces of Diesel 911 to 40 gallons of diesel fuel. This ratio can change depending on how many gallons are in your fuel tank and whether you are using diesel or biodiesel fuel, so make sure to check with the Power Service Diesel 911 instructions to adjust the ratio based on your fuel tank.

Remove the fuel filters on your vehicle and fill them with 50% Diesel 911 and 50% diesel fuel. Reinstall the fuel filters back onto your vehicle and start the engine.

It’s essential to make sure you’re using fuel additives regularly to minimize any potential issues. 

Pro Tip: Before you fill up, heed our Warning on How Quickly Does Gas Go Bad?

Can Water Damage a Diesel Engine?

Water can cause a massive amount of damage to your diesel engine. The longer the water sits in your fuel system, the more extensive the potential damage to your vehicle can be.

Water in your diesel engine can eventually create rust and eat away at it. Over time the steel and iron components may disintegrate. Steel and iron shavings traveling through your system can cause a host of issues for your vehicle.

If you suspect you have water in your system, take action immediately.

Have you ever had to deal with water in your diesel fuel? Tell us about your experience in the comments!

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