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Car Smells Like Gas When AC Is On – Here’s What You Need To Know

Car Smells Like Gas When AC Is On – Here’s What You Need To Know

Many people might wonder why their car smells like gas when they turn on their air conditioning, and for a good reason. This can be a sign of something serious and detrimental to your car’ sheath that you need to check out right away. If you have the same question as millions of other car owners, you might need to find out why your car smells like gas when the AC is on, what needs to be repaired, the potential reasons this is happening, and how to fix the vehicle.

Auto Repairs Are EXPENSIVE

Car Smells Like Gas – Why?


Let’s start by finding out some of the potential reasons why your car smells like gas when the ac is o


  • Gas Cap 



When you find out that your car smells like gas when the ac is on, it is very crucial to check the car’s gas cap first and foremost, sometimes the check engine light or the car smelling like a gas can be due to a serious problem. This problem could be the car’s mass airflow sensor not working correctly, or something inexpensive and less severe, like the fuel cap being loose after filling up your tank. 


You can figure out if the gas cap and the gas tank are the main issues of the car smelling like gas when the ac is on by opening the tank and checking the gas cap. If you find that the gas cap is loose or it can easily twist loose during driving, then the gas cap is your culprit. Additionally, you need to also inspect the longevity and the health of the gas cap to make sure there are no cracks or damaged parts that can turn on the check engine light or cause your car to smell like gas when the ac is on.


A broken or damaged gas cap can leak the fumes from the fuel tank into the car’s cabin, resulting in the car smelling like gas when the ac is on. However, it is fairly easy to make sure that the gas cap is not the culprit and keep the cabin passengers safe, by the check engine indicator that shows any leaks within the engine and fuel tank


  • Gas Exposure



If you are wondering why you smell the fumes and the fuel, but you do not notice any leaks in your car, this could be your answer. The main reason why a car smells like gas when the ac is on, but there are no leaks is the presence of gas exposure. Sometimes, the fumes from the gas tank from the pumps of gas stations can permeate the cabin of your car if you leave the windows or doors open, causing the smell to leak into the vehicle.


In order to get rid of this problem of the car smelling like gas when the ac is on, you need to just air out your car by rolling down the windows and driving your car for a few minutes, letting your car get some fresh air into the cabin. If the gas odor doesn’t come back after you try this solution, then you have successfully fixed the problem, and you do not have to worry about the car smelling like gas when the ac is on. However, if the odor still remains in the vehicle, then you need to continue looking for the main cause of the car smelling like gas. 


  • Broken Canister



The canister is the main mechanism connected to the fuel tank to catch excess vapor, toxic fumes, and charcoal coming from the fuel tank. This process minimizes the emission and harmful toxins that leave the system, helping to filter out the products. If the canister has worn down over time, broken due to prolonged use, or faulty due to improper installation, this can cause the gas fumes to come through the damaged vents or seals, leading to the car smelling gas when the ac is on. 


  • Gas Leaks



Another potential reason for the car smelling like gas when the ac is on is gas leaks inside of your vehicle. You can check for gas leaks and harmful fluids leaking in your car by inspecting your car’s underside. The easy way to do this and see if a liquid is leaking under your car is to check where your car has been parked for multiple hours or overnight, seeing if a puddle has accumulated beneath the vehicle. If the car has formed black puddles, then there are several things that you need to analyze to see why the car smells like gas when the ac is on.

Fuel tank

When looking for the car smelling like a gas while the ac is on, the gas leaks are the main reason why this smell enters the cabin. One of the conditions that can lead to gas leaks is the fuel tank being damaged. Punctured or broken fuel tanks can cause gas leaks, especially if they have worn down over time. The best way to fix this issue is to remove the old tank from your car, so the mechanic can inspect the fuel tank, repair any faulty parts, or do a complete replacement of the fuel tank. 


Furthermore, the leak in the fuel tank can cause the unburnt gas to emit from the fuel system and change into a vapor. To prevent this unseen vapor from entering your cabin and harming the passengers, you need to bring your car to a local auto body shop to fix the fuel tank’s gas leaks. 



The injector leaks that can cause gas to flow from your car can be caused by leaks from the o-ring seal or the rubber. Every type of injector has a rubber seal positioned at the bottom and the o-ring positioned at the top, with these components being key mechanisms to keeping the seal formed. 


Unfortunately, because the o-ring and the seal are so imperative to the injector’s proper sealing, they are also susceptible to wear and tear and are especially prone to damage. To Fix the problem of excess dryness, you need to replace the damaged o-ring and seal. Your mechanic can determine the overall health and function of the hte injetor condition by opening the hood and checking the fuel injector. Turn the engine on and find out if this is the reason why your car smells like gas when the ac is on. 

Fuel – Injection Line


Finding a leak in the fuel line can be a key reason why your car smells like gas when the ac is on. This leak can cause a very strong fuel odor once you stop your vehicle and park the car. The fuel injection line is usually in charge of containing a higher pressure in the lines, with the pressure in modern cars ranging from 60 psi to 125 psi. If you notice any fuel injection issue, like a weak fitting, the fuel will reduce the internal pressure. 


Finding any leak within the fuel injection line is crucial to the passengers’ safety in your vehicle and to find out why the car smells like gas when the ac is on. If the leak is located near the exhaust or the engine, the leak can cause a potential fire or excess friction. Furthermore, the gas mist is very dangerous for health, since breathing in toxic fumes can harm your airway and mental capacity. 

Fuel Line


Lastly, the final part of your fuel system that can cause gas leaks is the fuel line itself. This part connects the fuel tank and engine, but over time, debris and contaminants gather with the fuel lines or crush them. If the fuel lines cannot transport fuel between the tank and the engine, the car will smell like gas when the ac is on. 


  • Bad Fuel Pressure



A further reason why your car might smell like gas when the ac is on is due to a damaged or broken-down pressure regulator. The failed pressure regulator can cause your vehicle to burn excess fuel, causing the air to fuel mixture to become too rich or too thin to run properly. Burning excess fuel can cause gas fumes to accumulate inside of the exhaust system, with the gas fumes entering the vehicle if the leak crosses the ventilation. If this is the case, the smell, loss of power, and reduced fuel economy will alert you to a failed pressure regulator.


  • Old Cars



Another reason why your car might smell like gas when the ac is on is due to the production year of the vehicle you are driving. Along with the make and model of your car, the vehicles made in the early 1980s or the 1990s have different fuel systems than the modern vehicles. This causes the older cars to release the smell of the gasoline after the car is turned off.


The gasoline smell happens due to the afterboil of the fuel, meaning that it continues to burn after the engine has been shut off. If you notice the car smells like gas when the ac is on only after shutting the car off, then this is normal. However, if the fuel odor remains after the car has turned off and does not go away over time; this is a problem. 


  • Mold and Bacteria



One of the main reasons why there might be a distinctive fuel smell coming from your car when the air conditioner is running is due to the growth and accumulation of mold and bacteria within the vents. The smell of mold in your car might be caused by excess bacteria remaining in the fuel lines. 


Once your car becomes older, or if you have already purchased a used car or early-model car, fungi and mold can begin to grow within the fuel lines and the fuel system. This bacteria’s growth is usually located on the evaporator, which is directly connected to your car’s ac. This causes the car smelling like gas when the ac is on. 


By turning on the air conditioning system, you can sometimes encourage bacteria growth. If you frequently turn your ac system on to the highest setting, this can cause excess water to accumulate within your unit. 


To find the mold growth within the fuel system, you or a mechanic need to find the drain tube in the ac unit. Make sure that the drain unit does not have any damage, such as cracks or tears. Use the anti-bacterial treatment in your vehicle to get rid of the bacteria that has formed behind the dash panel or the evaporator. By injecting this fluid, you can reduce the car smelling like gas when the ac is on. 


  • Dirty Air Filters



An additional reason why your car might smell like gas when the ac is on is due to a damaged, debris-filled, or broken air filter. If the air filters are not cleaned between uses and at regular intervals, the air filter can collect contaminants and harmful pollutants that can harm the air quality in your car and the smell in your cabin. 


  • Antifreeze



If the cooling system smells sweet and less like gas, when the car’s ac is on, then this can be a reason to check your filtering unit, air system, and fuel system as soon as possible. The sweet smell when the ac is on is usually caused by the release of toxic liquids in the fuel system, like ethylene glycol. The smell of antifreeze and the sweet odor is the result of a leak, and can become especially prevalent when the ac unit is on. 

What is the cost of the AC antibacterial treatment?


To fix your car smelling like gas when the ac is on, you might need to undergo certain procedures in your vehicle, like paying for an antibacterial treatment. There are certain kinds of antibacterial cleaners that you can use periodically to prevent mold buildup, or cleaning your AC once a month to ensure filtered air. The cost of these products generally costs around $15 per bottle, with more extensive combination products ranging between $45 and $100. 


A fuel injector o-ring is another part that might need to be replaced in order to fix the fuel injection system. The average cost of the o-ring will cost about $15 for a complete set, while the typical run-of-the-mill choice you can get from an auto body shop will range between $13 and $15. 


If the problem of the car smelling like ac when the gas is on has become worse over time and the new o-ring and liquid does not fix the fuel system, then you might need to install a new car filter every 5-10k miles. These car filters generally range between $40 and $200 for the new parts to prevent the car smelling like gas when the ac is on.