How to Identify and Fix a Gas Leak in Your Car

Learn the symptoms of a gas leak in your car, possible causes, and estimated repair costs.

IMPORTANT: A gas leak is very dangerous for you and those around you because gasoline is highly flammable and can easily lead to explosions.

The safest thing you can do if you suspect a gas leak is to turn the engine off and get it towed to a mechanic.

If you suspect this issue, it’s important to get this fixed as soon as possible.

Just because your engine will still start and run without a problem, doesn’t mean that you’re safe.

Your car’s fuel can easily leak into the hot components of your vehicle—like the exhaust or engine—and ignite. 

Symptoms of a Gas Leak in Your Car

Look for the following signs that your gas may be leaking:

  1. You smell gas.
  2. You notice a drop in fuel/poor fuel economy.
  3. You see puddles of clear liquid under your car.

    1. You Smell Fuel

    A telltale sign of a leak is smelling gasoline when you are in and around your car, whether you are parked, idling, or driving.

    If you’re not sure what to smell for, many people describe it as smelling sweet. You’ve probably smelled it while filling up at the gas station.

    When you don’t have a leak, your car’s combustion chamber quickly burns the gasoline, causing it to evaporate. If you’re noticing a lingering gas smell, this indicates the fuel is leaking or escaping into the air. 

    2. You Notice a Drop in Fuel or Poor Fuel Economy

    Another common sign that you have a gas leak is a large drop in your fuel gauge.

    Sometimes, drivers may mistake this as poor fuel economy.

    As you know, your vehicle is going to naturally consume gas as you drive.

    However, if you’re noticing a sudden dip, this is a sign that you’re losing more than the normal amount of gas.

    This can happen both when you are driving or when you are parked. It will likely be accompanied by the smell of gas.

    3. You See Puddles of Fuel Under Your Vehicle

    Look carefully for puddles of gas underneath your car. Unlike oil and other car fluids, gas dries fast.

    It may be hard to catch gas puddles unless the leak is severe.

    If you notice a puddle, you can smell it to determine if it is gas.

    Keep reading to learn more about the different potential causes of gas leaking from the bottom of your car.

    Common Causes of Fuel Leak 

    These are the most common causes of fuel leaking out of your car.

    Leaking Fuel Hoses or Lines

    Your car has fuel pumps that move gas from the tank to the gas lines.

    When faulty – whether rusted, improperly fitted, or just run down – they will leak.

    In this case, you’ll notice the leak coming from the bottom of your car.

    Bad Rubber Seals 

    O-rings are seals placed on your car’s injectors to prevent unwanted liquids, like oil, from leaking into the combustion chamber.

    Because these seals are frequently exposed to high heat, they can wear down over time.

    This is another problem that could cause gas to leak underneath your car.

    Leak in the Fuel Tank 

    This one is pretty straightforward, yet it is one of the most common causes of gas leaking from the bottom of your car.

    Ideally, when you gas up your car, the fuel is held by the gas tank.

    If that tank is damaged or leaking for any reason, this is a huge threat to the safety of the vehicle. 

    Bad Gas Cap

    The gas cap that you remove to refuel your car is an important tool to prevent fumes from entering the air and the gas from leaking.

    If your cap is faulty, you may be noticing your gas leak.

    Even if this isn’t causing a leak, it is still dangerous because you’re allowing the fumes of the fuel to escape the chamber. 

    Estimated Cost to Repair a Car’s Gas Leak

    As with many other car issues, the cost of repair is totally dependent on what the problem is.

    A gas leak can cost anywhere from $150 to $1,500 to repair.

    You can discover what to expect by getting a quote from your mechanic upfront once they’ve had a chance to diagnose the issue.

    Is it safe to drive if your car is leaking gas?

    No. If you suspect your vehicle is leaking fuel, you should not drive it.

    Get it professionally repaired as soon as possible.

    Can I fix a gas leak by myself?

    Because of the dangerous nature of gas leaks, it is best to get a professional to diagnose and fix the problem.

    If necessary, they will identify and fix or replace the damaged car part and very carefully drain the system.

    We recommend getting a quote before the mechanic starts work on repairing your car’s gas leak because the price of a fix will vary quite significantly depending on what the problem is.