Car Smells Like Gas When A/C Is On

Your car should feel like a safe place to be, and a strange smell coming from the vents can catch many drivers off guard. In particular, smelling gasoline coming from your air conditioning vents raises many alarms for the average driver. Let’s see if we can see why smells come through our air conditioning and what they can mean. 

Common Smells That Come From A/C Vents 


A very distinct smell you will notice coming from your air conditioning vents is the smell of gasoline. Depending on the root cause of the issue, this could be a very minor or very serious problem., Because gasoline is such a strong and potent smell, you can recognize it immediately if it is coming inside your car. 

Many smells of gas are just from leftover gas from filling up the car, but there are more serious issues that can also cause the smell to emanate. Anything from a gas leak to an engine issue can cause the smell of gas to come through the air conditioning vents. 


Nothing smells quite as distinct or unpleasant as mold within your a/c vents. When your car ages and more air has gone through the air system, the likelihood of some form of mold growing in the system increases with time. To cool down the air in the vents, water is used and can cause mold as it drips over time. 

To prevent mold from forming, make sure you are not always blasting your cool a/c so less water is being produced. Additionally, you should also get the a/c system inspected to check for leaks and other issues. 


Dirt and unpleasant smells can come into your car if you neglect to clean out your a/c system. Unlike mold that forms from within the a/c system, dirt and dust that smells bad is something that comes into the car from the outside. As your car takes air in to cool your down, more dirt and small particles have the chance to get into your car. 

Sweet Smells

Despite sweeter smells not being as bad as issues like dirt and mold, this can be a warning sign that should not be ignored. In many cases, this sweeter smell is caused by an issue with the car’s cooling system that uses antifreeze and coolant. This coolant has a powerful and sweet-smelling odor that can be toxic and should be addressed quickly. 

Reasons You Might Smell Gas When You Turn On Your AC

Engine Running Condition 

Every engine seems to have it’s own personality and way of taking in fuel. Because of this, some engines can run rich as they add too much fuel to the engine. This is not a serious issue that can’t be driven with, but it will produce a strong gasoline smell and should be looked into ASAP. 

Fueling Issues

Even though filling up a car seems easy enough, even something like a single drop of gas missing the tank can emit a powerful smell. Tanks can overflow if you are not monitoring how much fuel you are putting in and some excess gas can drip out as you remove the pump from your car. 

Additionally, not putting your gas cap back on your car can cause you some serious pain in the long run. If you want to prevent these simple issues, make sure you are pumping gas yourself and not leaving the pump unattended and that your gas cap is free of cracks or holes. 

Gas Leak 

One of the most serious issues that can cause you to smell gas from your a/c is a gas leak. Gas leaks are a serious issue that you want to address as soon as possible. Gasoline leaks are dangerous because they can start serious fires and will cause your engine to have a bad day.

To spot a leak, you can look under the car and see if any fluids are coming out of the car. If you can’t see leaking fluid but still smell gas, you should stop the car and call a mechanic.

What To Do If You Smell Gas In Your Car

Stop The Car

The first thing you can do if you smell gas and are worried it could be an issue is to simply pull over and stop the car somewhere safe. Leaving the engine running and trying to drive if an issue is present is a recipe for disaster and will only worsen the bad condition. 

Once your car is stopped, you can let it sit for a while and see if the smell goes away. If you are worried about the issue, don’t start driving again until it is resolved. 

Look For Common Issues 

When a car smells like gas when ac is on, you can do a few things to try and diagnose the issue. If you can see under the car when it is stopped, look to see if any fluids are leaking. This is a sign that a fuel line is damaged and needs to be repaired. If this is the case, do not start or drive the car. 

If there are no leaks, open the fuel door and see if the fuel cap is properly screwed down. This is also a good time to make sure the cap is free of cracks or holes. 

Call A Mechanic 

When you just can’t figure out what is wrong, call for a mechanic. These people are specially trained to understand what is wrong with cars and can sometimes figure out the cause of a problem over the phone. 

In worse cases, the mechanic can come and take your car away to be looked at. This way, they can do a deep dive into the engine and gas system to see if there are any issues. This is also a great time to have them look at your a/c system to see if any mold or debris is in there that we mentioned earlier.