Car Smells Like Gas? (5 Causes and the Seriousness of Each)

Last Updated on October 8, 2021

When you’re driving down the road, the last thing you want to deal with is a strong gas smell. But not only is it inconvenient, but it can be extremely dangerous.

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But is it always serious? Here we look at the five most common reasons your car might smell like gasoline and how serious each issue may be.

Related: Engine Oil Smells Like Gas?

Causes of a Fuel Smell From Your Vehicle

There are various causes of gas smells coming from your vehicle, and they range in seriousness. Some problems you can ignore until the new parts come in, and others you shouldn’t even drive to the repair shop. We’ll break down everything you need to know here.

#1 – Loose, Missing, or Damaged Gas Cap

inspect fuel cap

One of the most common causes of a fuel smell in your vehicle is a loose or damaged fuel cap. If you just filled up, go and double-check that the fuel cap is tight (and actually there). From there, take a look at the gasket and seal. If everything looks good, then this isn’t the cause.

However, if the cap has a torn gasket or cracked, this is likely where the smell is coming from. As a final note, if you did just fill up, give it a few miles before diving into anything too far. Fuel vapors can travel while filling up, and this can lead to a temporary smell inside your vehicle.

Seriousness: LOW

While this isn’t an extremely serious issue, it’s incredibly affordable to fix. Because of this, there’s no reason not to get a new gas cap on order and replace it as soon as you can.

#2 – Leak in the Fuel System

fuel filter replacement interval

There are tons of components in your fuel system, and over time they can break down in various ways. Fuel lines are notorious for rusting, while dented fuel tanks can crack and lead to leaks too. Moreover, gaskets and seals can give way, all of which can lead to a fuel leak.

If you have a fuel smell, finding a fuel leak is relatively straightforward. Just follow the smell, and it should lead you straight to the leak!

Seriousness: HIGH

This is the most serious cause of a fuel smell in your vehicle. Leaking fuel is extremely dangerous, and you should not drive your vehicle if you suspect or find a fuel leak.

#3 – Loose or Damaged Spark Plugs

Your combustion chamber is where the fuel mixes with air, and the spark plug ignites the entire mixture.

While this usually is a flawless process, if the mechanic didn’t torque the spark plugs correctly when installing them or if the spark plugs have a broken seal, the ignition can send fumes straight out the opening and create a fuel smell.

If you suspect this is the problem, you should replace all of your spark plugs. The good news is that this isn’t extremely expensive, so you won’t have to break the bank to fix the problem.

Related: How to Check Spark Plug Condition

Seriousness: MEDIUM

While the likelihood of anything serious happening is low, a loose or damaged spark plug can lead to serious problems.

That’s because you have all the conditions to ignite the fuel and air mixture, but it’s not all fully contained in the combustion chamber. Repair the problem as soon as you get a chance.

#4 – Engine Running Rich

engine running rich symptoms

There is a correct fuel to air ratio to get maximum performance, but when things aren’t running the way they should, that ratio can be a little off. If the ratio is running rich, that means there’s too much fuel in the combustion chamber.

Your vehicle won’t be able to burn it all off, so fuel vapors will escape through the exhaust. This leads to a strong fuel smell right outside your car, especially right when you start your car.

Seriousness: MEDIUM

Outside of significantly reduced fuel economy, there aren’t a ton of short-term concerns with an engine that is running rich.

However, if you leave the problem for an extended period, engine damage can result from the excessive force the extra fuel causes.

#5 – Faulty Charcoal Canister

bad charcoal canister symptoms

Your vehicle charcoal canister is a critical part of the EVAP system. It collects fuel vapors from the exhaust and forces them back into the combustion chamber to burn again.

This is great for the environment because by double burning the fuel, it generates fewer harmful emissions. However, if the charcoal canister is cracked or faulty, all the fuel vapors it’s collecting will escape and generate a fuel smell.

Seriousness: LOW

While having a faulty charcoal canister is bad for the environment, it’s not a huge deal when it comes to performance or safety. As long as the vapors stay on the outside of your vehicle, it’s not a huge concern.

What To Do if You Smell Gas in Your Car

burning smell

Inside the Vehicle

There’s a big difference between smelling gas around your car and smelling gas in your vehicle. While both can be extremely serious, it can quickly turn deadly if you’re smelling gas inside your car.

Getting a fuel smell inside your car is especially common when the heat is on, as it brings in whatever smells are inside the engine bay. So, if you have a fuel smell inside your car, it’s best if you turn both the heat and A/C off and track down and repair the problem immediately.

Outside the Vehicle

Meanwhile, if the smell is exclusively on the outside of your vehicle, you’ll still need to track down the cause of the smell as soon as possible. Start by checking the fuel cap since it’s extremely easy and quick to check.

But if that’s not the problem, see if you can’t track down the source of the smell by simply following the smell. This usually will lead you straight to the problem. If not, you need to give the entire fuel system a thorough check.

This means checking the fuel tank and all the fuel lines to ensure they don’t have any leaks. If there are no leaks in the fuel system, you might have a faulty charcoal canister or an engine that is running rich.

An engine running rich will have a fuel smell coming from the exhaust, while a faulty charcoal canister will have the smell coming from the engine bay. If you can’t track down the problem yourself, you need to have a professional take a look at it.

Trust your nose because an undiagnosed fuel leak can lead to an extremely dangerous situation.

 

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