How to Clean Fuel Lines on a Car? – 5 Detailed Steps

Written by

Bruce Sonnier


Marcus Dutton

how to clean fuel lines on a car

The fuel system is a critical part of your car as this part keeps your vehicle moving. It needs to be taken care of and checked once in a while. Rust and gummy build-ups on your fuel lines may cause blockage and problems in your car’s system.

If you feel like there must be a problem with your fuel lines, or you find any leaks, do not hesitate to get it fixed by a mechanic. However, you can do the work successfully on your own by following this guide on how to clean fuel lines on a car.

What to Prepare


  • Ramps (optional)
  • Working gloves
  • Fire extinguisher
  • Hand tools (socket set and screwdrivers)
  • Air compressor with a nozzle
  • Gas line cleaner
  • Brake line cleaner
  • Ethanol or Rubbing Alcohol (alternative)
  • Catch basin
  • Garden Hose
  • Water source

Step 1: Elevate your car and disconnect the battery terminals


After preparing the materials and tools, drive your car and position the back wheels on the car ramps for elevation. This step is optional but recommended so that you can work easily below your car.

  1. Before you start on your fuel lines cleaning work, put on your working gloves.
  2. Also, make sure that no fire starter is around. Put a no smoking sign if possible, and keep your fire extinguisher near.
  3. Then, open the car’s front cover to expose the engine and make sure that the negative battery terminal is disconnected from your battery. You might cause problems like fire and sparks when cleaning the fuel line without removing it.

Step 2: Locate your fuel lines and disconnect them from other parts of the fuel system.


Most cars have different builds of their fuel system. Find your car’s user manual to locate the fuel lines, and identify your car’s fuel system.

You can clean your fuel lines without the removal of your fuel tank.

1. Loosen the clamp that is on the end of your filling hose, and wiggle the hose until it disconnects from the tank.

2. Locate the top opening of your fuel tank which is usually located below your car’s back seat.

3. Open the cover by undoing the screws using a screwdriver. Once removed, you can see the fuel line/s attached to the fuel pump.

4. When you clean the fuel system in a car, you only put cleaners in the high-pressure fuel lines where the fuel flows.

For a single fuel pipe system, detach the only high-pressure fuel line from your fuel pump by popping and/or pressing the safety tabs.

For a twin fuel pipe system, locate two high-pressure fuel lines attached to your fuel tank and detach them by undoing the safety tabs or screws.

5. Lastly, go to the front of your car and disconnect the high-pressure fuel line/s from your carburetor or fuel rail, whichever is applicable.

Step 3: Flush the high-pressure fuel lines with cleaner


There are available fuel system cleaners in the market that are used to clean the fuel system in a car.

However, you must use a gas line cleaner like Lucas Upper Cylinder Lubricant & Fuel Injector Cleaner, which is used to clean fuel injectors and can clean gummed-up fuel lines due to its chemical composition.

  1. Place a catch basin on your fuel tank. Then, elevate the high-pressure fuel lines into the catch basin.
  2. On the other end of the fuel lines, inject or pour your cleaner and insert the air nozzle to use the compressed air to clean the fuel lines. You should see dirt or any debris in the basin.
  3. Use rubbing alcohol if a gas line cleaner is not available, as the composition of this alcohol will help clear a clogged fuel line.

Repeat this step as needed.

Step 4: Clean the fuel filler hose


Cleaning the filler hose is critical for fuel system cleaning because if this part is not cleaned thoroughly, dirty fuel will go inside your fuel tank.

Spray water into the filler hose, using the garden hose that is attached to a water source. Do this until you only see clear water coming out.

To force the water out and clean other debris or rust, pour rubbing alcohol using a funnel until the liquid that is coming out is clear.

Step 5: Put the disconnected lines back into the fuel system.

Attach back the fuel filler line into the fuel tank, and then tighten the clamps. Connect the high-pressure fuel lines back to the fuel tank or fuel pump, and also on the other end to the carburetor or the fuel rail.

When putting back all the lines, make sure that the safety tabs are secured and locked so that there will be no leaks.

Do not forget to attach back the negative battery terminal to the battery.

The Reasons of a Clogged Fuel System


  • Debris
  • Rust
  • Sludge from deteriorating materials on the fuel system
  • Carbon buildup
  • Other contaminants



How do you know if your fuel line is clogged?

Clogged fuel line symptoms are sputtering of the engine where the power goes on and off, clicking or sounds that are coming from the fuel tank, RPM going down often, and running out of gas frequently even if you just filled it up.

Do you need to clean fuel lines?

Yes, fuel lines can be replaced if you want. However, perfectly fine fuel lines that still serve their purpose on the fuel system just need cleaning for their best function.

What are the benefits of cleaning a car’s fuel lines?

  • Cleaning your car’s fuel line extends the life of your engine.
  • It also prevents rust and corrosion that damages your fuel system.
  • It improves the performance of your car.
  • And avoid damage to your car’s whole system.

Easy way to clean brake lines:

After locating the brake lines, inject or pour brake line cleaner into the brake lines, and then use compressed air to remove the mixture of debris and liquid. Cleaning brake lines with alcohol is also recommended by many mechanics if a brake line cleaner is not available as alcohol easily evaporates.

Let the lines air-dry for an hour or so.


Fuel lines need to be cleaned to maintain the quality of your car. Those can be easily replaced but car parts and repairs are pricey these days. Some will pay for the work as it is urgently needed.

However, if you’re willing to dedicate your time and do the work, this ‘how to clean fuel lines on a car’ guide will not fail you. Just get the materials needed and follow the steps! I hope this helps you a lot!

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