How To Fix Gas Leak In A Car?

If you have been searching on the internet for ways, how to fix a leaking gas tank, chances are, you might be dealing with one. Whether you are dealing with a leaking gas tank or you are just trying to learn how it’s done, it is important that as soon as you notice a gas leak on your vehicle, you need to get it done immediately.

Knowing how to fix a leaking gas tank can help you get an idea of what needs to be done to stop the leaking. It usually involves draining the tank, locating the leak, cleaning the tank, covering or patching small leaks with a gas tank sealer, or welding the larger ones.

However, there is much more than this process of patching and welding. There are things that you need to do to ensure that you are doing it properly. It can be risky. You can either take your vehicle to a repair shop and have the gas tank fixed or fix it yourself and save some bucks.

You need to know how to fix a leaking gas tank the right way and the safe way. You also need to know what causes it, how to spot a leaking gas tank, and everything you need to know!

How To Fix Gas Leak In A Car

3 Common Symptoms of a Car Gas Leak

The fuel tanks of most cars are strong enough to withstand varying temperatures, pressures, and most road elements. But like other parts of a car, it’s going to wear out over time. Once that happens, it could spring a leak.

If you think your car’s fuel tank is the problem, the best person to consult is your mechanic. You should also look for these signs of a car gas leak:

1. Slight Sweet Smell

Gasoline has a naturally sweet smell. According to the United States Agency for Toxic Substances and Disease Registry (ATSDR), benzene is the substance responsible for its distinct smell, which helps boost your car’s performance and gas mileage.

You may sometimes catch a whiff of gasoline when you’re driving or when your car’s idling. However, the smell should immediately disperse as it evaporates or ignites in the engine. If the smell lingers or becomes stronger, pay closer attention to other symptoms of a leaking fuel tank.

2. A Big Drop in the Fuel Gauge

Checking your fuel gauge levels is perhaps one of the simplest ways to know if you have a leaking problem. However, it’s not a foolproof method. Your car needs to lose large amounts of fuel for you to be able to tell that there’s a leak.

First, you need to note where the needle is pointing on the fuel gauge while your car is parked (with the engine off). Then, start your car again. The fuel level on the gauge should be the same as when your car wasn’t running. But if there’s a leak, it could show that you’re running low on fuel.

Other Things to Watch out For

  • The level of gasoline in your tank slightly or significantly falls even when your car hasn’t used that respective amount of gasoline.
  • The gauge shows that you’re still running low on gasoline after refilling your tank.
  • You keep refilling your gas tank to move your car at the same distance and speed.

3. Puddle Under Your Car

Get your car’s user manual to check the exact location of its fuel tank (if you still don’t know yet). Once you know that, pay attention to the spot directly underneath the fuel tank to look for wet spots.

If you parked your car on a paved or gravel road for a long period, you’d usually notice a small puddle of gasoline that’s brown or orange in color. If you parked it on or near grass—which you should avoid—the fuel leak could cause the grass to discolor and die fast.

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6 Possible Causes for Gas Leaks in Your Car

There are many reasons why gas leaks from your car, ranging from minor to major issues, which you need to fix immediately. To give you some ideas, below are a few common reasons for gas leaks in cars

1. Worn Out Fuel Tank

During the entire service life of your car, you might need to replace some major parts of the fuel injection system, like the fuel filter and fuel supply pump. The fuel tank rarely needs replacement—that is, if you take good care of it.

However, your fuel tank may rot and fail over time because of moisture or natural wear and tear. It can also develop leaks because of road debris, such as road salt. If that happens, you might need to replace the entire tank.

So, how long do fuel tanks usually last? If it’s made of steel or aluminum, it will last for a minimum of ten years. A new fuel tank could cost between $1,094 and $1,160, excluding the cost of labor.

2. Leaking Fuel Lines and Hoses

The function of the fuel lines is to deliver fuel from the fuel tank to the engine to make your car actually run. These lines can normally handle a lot of pressure and last anywhere from 50,000 to 75,000 miles. But oftentimes, leaks develop in such areas, especially the hoses.

Leaks happen in the lines because of different reasons. It could be due to a damaged hose, which frequently results from improperly sealed mounting points. Other reasons could be rust and wear. That’s why it’s important to have your fuel lines, particularly the fuel vent hose, regularly checked.

Unfortunately, once a fuel line leaks, it can’t be repaired. Thus, you need to replace it.

Signs That You Need to Replace Your Fuel Lines

Here are three signs you need to watch out for to know if your fuel lines need replacing:

  • A noticeable gas odor will come from your car.
  • Your car may turn on but it will immediately stall because of the low fuel level.
  • Your car will not turn on because there’s not enough fuel in the combustion chamber.

3. Using Fuel Additives

Many of the fuel additives on the market are harmless. In fact, they can help plug small engine leaks (at least temporarily) and maximize your car’s fuel efficiency.

While they’re generally safe, some additives can damage the fuel supply system of your car, one of which is acetone. Apparently, some people add 1 to 3 ounces of acetone per 10 gallons of gasoline to boost their car’s mileage by as much as 25%.

Using acetone to increase gas mileage doesn’t work at all. Worse, this corrosive substance could damage your engine and other major components of your fuel supply system (e.g., gaskets and O-rings). This would eventually cause leaks. That’s why car manufacturers strongly warn against the use of acetone in your fuel system.

4. Damaged Gas Cap

The gas cap isn’t just for preventing fuel from coming out of the tank. It also serves other essential functions, such as:

  • Maintaining the correct pressure inside the fuel tank, and
  • Preventing gas fumes from escaping from the tank.

In most cases, a cracked, damaged, or missing gas cap is the reason for the leaking and smell of gas in your car. So, you might want to consider buying a new one to ensure your car’s fuel supply system works as intended.

5. Damaged O-Ring or Rubber Seal

Leaking doesn’t always occur in the fuel injector. But if it does occur there, the most likely culprit is defective O-rings. Because these gaskets are exposed to the engine’s heat all the time, they could become hard and brittle. This prevents the fuel injector from staying tight against the engine to prevent leaking.

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To determine if this is the problem, inspect the area around the oil filler cap. If you notice any debris or oil residue on the valve cover, check the O-ring for any signs of damage. If it’s cracked or brittle, get your mechanic to replace it and other damaged components.

6. Excessive Vibration

It’s not unusual for your car to vibrate when you’re driving because of its various moving parts, such as:

  • Crankshaft,
  • Engine,
  • Suspension, and
  • The transmission gears slightly.

But if the vibration is excessive, it could damage your fuel tank and put a lot of stress on your car’s structural parts, causing them to fail after many cycles.

Again, what causes a gas leak? Gas leaks usually result from a problematic vent hose connected to your car’s fuel tank. When not detected, it can cause a fire.

How Do You Fix a Leak in A Metal Gas Tank?

Knowing how to fix a leaking gas tank can come in handy when you have to deal with one in the future. There are several methods you can use to fix a leaking gas tank. What method you choose really depends on how big the hole in your tank is that causes it to leak.

For small leaks or holes, you can use an epoxy putty or a gas tank sealer. Gas tanks that are leaking caused by big holes might need to be welded to be fixed.

How To Fix Small Holes Using a Gas Tank Sealer or An Epoxy Putty.

A leaky gas tank can not only cost you a lot of money in wasted fuel, but it can also be very dangerous and result in a potentially deadly fire or explosion. So, fixing a leaky gas tank needs to be done as soon as the leak is noticed.

You can take it to a repair shop and spend a lot of money, or you can do it yourself and save yourself about $100. Here is a quick guide on how to easily repair a leaking gas tank on your vehicle.

What You Will Need

  • Gas tank repair epoxy putty compound
  • Car jack
  • Jack Stands
  • Sandpaper
  • Rubbing Alcohol or another degreaser
  • Clean towel or rag
  • Vinyl or kitchen gloves
  • Safety Glasses
  • Filtration mask

Step 1 – Jack up the Vehicle

Jack up the car to a height where you can place the jack stands underneath the vehicle. Once the jack stands are underneath the vehicle, lower the jack to a height so that the vehicle rests safely on the jack stands while you are working underneath the car.

Step 2 – Find the Leak or Hole in the Gas Tank

Crawl under the vehicle and inspect the gas tank. Find the area where the tank is leaking or where there is an obvious small hole where the gasoline drips or leaks out.

Step 3 – Sand the Leaky Area of the Tank

Use the sandpaper to sand the area where the tank is leaking. Sand an area approximately 1 1/2 inches to 2 inches in diameter surrounding the hole or leak in the gas tank.

Step 4 – Clean the Surface

Use the towel and alcohol, or another degreaser, to thoroughly clean the area that has been sanded. Make sure to remove any dirt, grease, or grime that will prohibit the epoxy from being applied or curing correctly.

Step 5 – Mix the Epoxy

Follow the manufacturer’s instructions for mixing the epoxy compound. You may have to mix the compound from two different tubes together for a couple of minutes and be sure to use it before it dries. Follow the instructions on the packet exactly for mixing the compound.

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Step 6 – Shape and Apply the Epoxy

Next, cut off a piece of the compound that is about 1 to 1 1/2 inches long. Then shape the epoxy compound into a small cone shape with a tip at the top and a wider or broader base at the bottom.

Step 7 – Insert the Epoxy in the Hole

Once you have correctly shaped the epoxy compound into the shape of a cone, you will need to insert the tip of the cone-shaped epoxy into the hole in the gas tank. Insert the epoxy compound as far as it will go into the hole and press and smooth the remaining compound into the area that has been sanded. You can use a couple of drops of water to make the smoothing process easier and help it blend better into the sanded material.

Step 8 – Fill the Tank with Gas

After the epoxy compound has dried and cured, you can fill your car’s gas tank as you normally would. Once you fill the tank, make sure to check the tank again for leaks. However, if you have followed the directions above, the leak should now be sealed and the epoxy should hold for many years to come.

How To Fix Larger Gas Tank Leaks or Holes?

  1. Just like the process of fixing small holes using a sealer, fixing larger gas tank leaks also requires you to drain the gas from your tank and make sure that it has been cooled down to room temperature.
  2. Jack up your vehicle so you can remove your gas tank. You can use a ratchet wrench to pull the fuel hoses off, then you can unscrew the bolts on the straps that hold the tank to the underside of the vehicle to disconnect the gas tank from it. Once done, gently lower the gas tank while squeezing the electrical wires’ wire clips to disconnect them.
  3. You need to clean the gas tank thoroughly to make sure that all the fuel has been flushed out. Welding a gas tank with fuel in it is extremely dangerous. This is the main reason why you need to learn how to fix a leaking gas tank the right way. The welding torch can ignite the gas fumes that could result in an explosion. To make sure that all the fuel and the fume has been flushed out, you can flush it out with hot water, scrub it off, dump the water, and allow the tank to dry in a sunny area that has a good air circulation. You can flush it out with water several times until it no longer smells like gas.
  4. You can then proceed to weld your gas tank to fix the leak. You can either get a plastic or a metal welder depending on what type of gas tank you are welding. Make sure that you are wearing protective gears like a welding mask and heat-resistant gloves. Work outdoors if possible so you can get proper ventilation while working. Keep children or pets away out of the area until you’re done welding.

When you know how to fix a leaking gas tank and understand the process, you can save some money by fixing it yourself instead of going to a repair shop. However, you also need to understand that it can be risky since you will be dealing with a leaking fuel that is known to be flammable. You need to make sure that every precautionary measure has been done before you proceed to fix your leaking gas tank.