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Summary
  • Some useful tips to consider when cleaning a gas tank include taking the necessary safety precautions, preparing all of your tools beforehand, and draining the fuel tank using the drain cock.
  • To clean the exterior of a gas tank, you can scrub the rust away with aquarium gravel or wash it with chemicals like vinegar and baking soda. You can also take the tank to the local car wash and blast the inside of it out with the high pressure wash wand.
  • A dirty gas tank can cause fuel pump failure, poor engine performance, and a clogged fuel filter.

You don’t have to clean your gas tank often, but there are specific instances where you’ll have to give it a good scrub. If your car’s been sitting in the garage for over six months or if you recently replaced the fuel pump, you’ll have to clean your gas tank. Doing so can certainly be a challenge, but it doesn’t have to be hard. Here are some useful tips on how to clean a dirty fuel tank:

Tips on How To Clean a Gas Tank

Taking the Necessary Safety Precautions

You have to take the time to go through a few safety precautions before you start the job. As much as possible, work outdoors in a clean, open area. If you have to work indoors, make sure there’s decent ventilation. Open all the doors and windows, and set up some fans to improve the airflow. 

It’s also a good idea to have a fire extinguisher within reach. Make sure there aren’t any open flames nearby, too. A coffee cup full of gasoline contains the explosive power of a stick of dynamite, so you can never be too careful when handling it.

Preparing Your Tools Beforehand

You’ll save yourself a lot of trouble by preparing your tools beforehand. Grab your toolbox, a container for your old fuel, and a cleaner for your gas tank.

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You can also wear a face mask and glasses to protect yourself from the toxic fumes. Remember: the best way to clean a gas tank is the safest way.

Inspecting the Fuel Tank

The first thing to do is to inspect the fuel tank. Check for any signs of rust, damage, or contamination. If you notice anything wrong, then you might have to replace it.

Draining the Fuel Tank

Now, if you want to clean your dirty gas tank, you’ll have to drain the fuel first. There are different ways you can do so. You can siphon it, use a gas line, or use the tank’s drain cock if it has one.

If the in-tank fuel pump still works, you can disconnect the fuel line from the filter and extend it into an approved container large enough to contain the remaining gas. Then, bypass the fuel pump relay and let the pump empty the tank for you.

When siphoning, try not to use your mouth. There are tools available online and at places like Walmart for siphoning. Use one of these if you plan to siphon the fuel, but make sure the hose reaches the bottom of the tank.

When siphoning, try not to use your mouth. There are tools available online and at places like Walmart for siphoning. Use one of these if you plan to siphon the fuel, but make sure the hose reaches the bottom of the tank.

Richard McCuistian, ASE Certified Master Automobile Technician
, Useful Tips on How To Clean a Gas Tank

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: The problem with siphoning is that most newer cars have an anti-siphon blocker, so you may not be able to get a hose into the tank through the filler unless you disconnect the filler hose from the tank, which you have to do anyway if you plan to remove the tank. But on vehicles with a fuel pump access panel under the seat or in the trunk, you can remove the fuel pump and directly siphon the gas out that way using your siphoning tool.

Keep in mind: siphoning is something you must do at your own risk. That’s about the size of it.

Removing the Gas Tank

Once you empty the tank, it’s time to get it out from under there. The process of removing the fuel tank varies depending on the vehicle’s engine type, so you’ll have to check how to remove yours. If you aren’t 100% sure, you can always ask a mechanic for help.

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There are straps to hold the tank, the filler hose to disconnect, and there are wires and hoses connected to the top of the tank, including hose connections for the evaporative system, and many of these are brittle plastic; break a hose nipple off a plastic tank and you’re going to need a new gas tank. Make absolutely sure everything is disconnected from the tank before lowering it.

Cleaning the Fuel Tank’s Exterior

image of an automotive gas tank
Trying to figure out how to clean rust out of a gas tank? If the rust is bad enough, just replace the tank. They don’t cost that much. The 91 Chevy gas tank (see photo) is available at CarParts.com for less than $200 and comes with tank straps. | Image Source: Richard McCuistian

There are actually several methods you can try to clean the tank’s exterior. Scrubbing the rust away with abrasive materials like aquarium gravel might work. If you have vinegar and baking soda at home, you can use them to wash your fuel tank too. The only problem with these methods is that you can’t access the entire interior of the gas tank by hand.

You can take the tank to the local car wash and blast the inside of it out with the high pressure wash wand. You can usually hit most of the inside of it this way, but you’ll need to position the tank so that it dries completely out, possibly with a small fan blowing into the tank after you wash it, or maybe a hair dryer or heat gun.

Removing the Fuel Pump

In most vehicles, you’ll find the fuel pump inside the gas tank. Remove it first before you clean your fuel tank.

, Useful Tips on How To Clean a Gas Tank

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: Even if the tank doesn’t have an internal fuel pump, it will have a fuel sending unit that should be removed before cleaning.

Swirling the Gas Tank

After removing the fuel pump, consider swirling the gas tank in a circular motion. This helps get rid of any leftover fuel or debris that’s still stuck inside.

Cleaning the Inside of the Tank

To give the inside of the tank a thorough cleaning, consider using a high-quality fuel tank cleaner. Make sure to follow the instructions printed on the packaging, including how much you should use.

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Fuel sludge and other debris usually build up at the bottom of the tank, so be extra thorough when cleaning that area.

Drying the Tank

Now that your gas tank is clean, you’re probably excited to reattach it back to your vehicle. Unfortunately, you’ll have to wait a while before you can do so. The fuel tank has to be completely dry before you refill it with gas.

Again, you can use a fan or a hair dryer or a heat gun to blow air into the tank and you can put the tank in the hot sun. Check regularly with a flashlight to see if there is still moisture in the tank. If you can get your hand in there with an absorbent towel, dry out any standing water.

Letting it dry for at least 30 minutes should do the trick.

Replacing the Fuel Filter and Pump

Replace your old fuel filter, too. If you haven’t replaced your fuel filter in a while, then now would be a great time to do so. And go ahead with a new pump if you can afford it. You won’t be sorry.

Refilling the Tank

When refilling your fuel tank, consider using fresh fuel instead of the fuel you drained out, particularly if the old fuel was contaminated.

Why Should You Clean Your Fuel Tank?

Cleaning your gas tank might seem like a lot of trouble, but it’s not something you can just put off forever. Sooner or later, a dirty fuel tank is going to cause problems for you and your vehicle. Here are a few examples:

Fuel Pump Failure

sample image of a dirty fuel tank
A dirty fuel tank (particularly if the vehicle has been parked for a long time) is one of the most common causes of fuel pump failure. The fuel pump in the photo is from a 1996 Mazda 626 that had been parked in a barn for a couple of years. | Image Source: Richard McCuistian

Poor Engine Performance

Notice any issues with your vehicle’s engine performance recently? It might be because of rust and other debris circulating in the fuel system, which may cause your engine to suffer from inconsistent fuel flow. You’ll experience acceleration and other performance issues. But remember to check everything else first.

Clogged Fuel Filter

A rusty fuel tank is likely to clog the fuel filter faster, causing pressure buildup, engine performance issues, and fuel leaks.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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