How to remove sludge from a gas tank

Written by melissa lowery
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Over time, sludge, trash and water can build up in your vehicle's fuel tank and cause your fuelling system to become clogged. This build-up of waste materials can also cause your gas tank and fuelling system to rust. Sludge build-up spreads throughout your fuelling system and causes fuel to back up, which in turn creates expensive damages and causes your car to burn gas more quickly. Removing this sludge saves repair costs and maximises your car's fuel efficiency.

Skill level:
Moderately Challenging

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Things you need

  • Protective clothing
  • Gloves
  • Safety goggles
  • Gas can
  • Gasoline
  • Siphon pump with connector tubes
  • Clean plastic storage container
  • Wrench set
  • Pliers
  • Water hose with pressure attachment
  • 1 cup baking soda
  • 2 cups white vinegar
  • Blow dryer

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  1. 1

    Dress in protective clothing, including thick gloves and safety goggles. Wear this protective gear throughout the entire sludge removal process. Fill a gas can with gasoline before beginning.

  2. 2

    Remove the lid from your gas tank, and insert the siphoning tube. Two tubes normally extend from the siphon pump; insert one into the gas tank and the other into a clean, safe storage container. Turn the siphon pump to remove all of the liquid from the gas tank slowly.

  3. 3

    Remove all of the hoses that connect to the gas tank using a wrench set and pliers. The amount and location of these hoses will vary depending upon vehicle make and model.

  4. 4

    Remove the gas tank from the vehicle. The gas tank removal tools and process will differ for every vehicle. Gas tanks are heavy; use precautions when lifting from the vehicle.

  5. 5

    Spray water into the gas tank using the water hoses and pressure attachment. Spray down the inside wall's well. If draining out the tank is a problem, remove the water with the siphon pump.

  6. 6

    Add 1 cup of baking soda and 2 cups of white vinegar to the gas tank. Fill the tank three-fourths of the way with water to create a cleaning solution that will break down and dissolve any build-up. Allow this solution to sit for at least an hour. For a deeper clean, the mixture can remain in the tank overnight.

  7. 7

    Drain the cleaning solution from the tank. Again, you can use the siphon pump to make this easier. Rinse the inside of the tank several times to remove any traces of the solution. Fill the tank, and rinse down all of its sides at least four times to ensure the tank is entirely free of any cleaning solution residue.

  8. 8

    Dry the gas tank with a blow dryer. Allowing any dampness to remain inside the tank will result in rust, which is dangerous to fuel systems.

  9. 9

    Reattach the gas tank and hoses to your vehicle. Add half the gas in the spare gas can to the tank to complete the cleaning and allow the vehicle to run.

Tips and warnings

  • Though many mechanics prefer muriatic acid when cleaning a gas tank, a solution of baking soda and vinegar makes an effective cleaner with less chemical hazards. If you choose to use muriatic acid, combine 85.1gr. with 2 tbsp of baking soda.
  • If using muriatic acid to clean the gas tank, use precautions; this chemical can cause severe damage if it comes into contact with your skin, mouth or eyes.
  • Properly dispose of all waste liquids removed from the gas tank.

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