What Are The Reasons Why My Car AC Stinks Badly?

Are you experiencing stinky smells from the AC in your car, when you switch it on? It seems so because your complaint is my car ac air stinks. That must be disgusting and unbearable, right? This is of course an indication that something is up with your car’s AC. This article tries to explain the several reasons why your car’s AC stinks and how to solve the issue. So read on!

My Car AC air Stinks: Why Is That?

Your car AC may send out pungent smells due to a variety of reasons. You should have the basic knowledge to be able to identify which smells indicate what the issue is. This section will let you give that basic knowledge to be more specific in your complaint, my car ac air stinks. So the common reasons why your car AC stinks so bad are

1. Mold And Bacteria

Are you identifying a mushy old smell from your car’s AC vents? If so, it indicates that mold and bacteria are breeding inside your AC system! This is one of the most common reasons that cause the complaint, my car ac air stinks. 

As your car gets older, bacteria, mold, fungi, and other microorganisms find your car, especially the AC vents, a perfect breeding place. Behind the dash of your evaporator is a place in your car that bacteria find very convenient to grow and breed. This causes a very unpleasant smell from your AC unit. The AC vents of your car have the perfect atmosphere for all the organisms to live and breed. Furthermore, keeping your car unused for a while will encourage these organisms to grow and breed in these places. 

Using your car’s air conditioner at maximum is also another reason for bacterial growth. This will result in the formation of excessive bacteria dripping in your unit. 

How To Fix?

You need to locate the drain tube in your AC unit first to try and fix this issue. Make sure that it is working well and not dripping excessively. The pungent smell now may be severe and this is a clear indication that there is bacterial growth in those vents. Use an antibacterial treatment that is capable of destroying the bacterial growth behind the dash panel. Inject the anti-bacterial treatment solution in the air conditioner case. It is then advised to turn off your car’s air conditioner for a while then. Let the fan alone run for a few minutes. This will help in evaporating the water on the coils of the unit. 

How Much Would An Anti-Bacterial treatment Cost?

A lot of anti-bacterial cleaners are available in the market. Once you get one, you can pretty much do all the cleaning on your own. The average cost of a normal anti-bacterial cleaner will be around $15 per bottle. They can quite last a long time too, so it’s worth a buy. 

2. Gas Leak

Does your AC smell like gas, every time you switch it on? Then your car may have a gas leak. When you switch on your AC the gas smell is being sucked into the fresh air that your air conditioner is taking. 

How To Fix?

Repairing the leak is of course the only fix in this situation. Gas leaks are also not something to be taken lightly and you have to get your trusted mechanic to fix them as soon as you notice a leak. If you can’t locate where the leak is, there are a few places you can check. Inspect the fuel pressure regulator of your engine for any noticeable links. 

There is the fuel injector “O” rings in the engine compartment that you can check for any possible leaks. It is also recommended to check your exhaust pipes and muffler for the presence of any holes that can cause leaks. 

3. Dirty Air Filters

Another something that can cause the complaint, my car AC air stinks are dirty air filters. The air filters are responsible for cleaning the air coming from outside before cooling it and sending it through our air conditioner. If these air filters are not cleaned regularly, dust and dirt will pile up along with stagnant water, dust mites, and other harmful pollutants. This of course will bring out a bad smell, every time you switch your AC on. 

How To Fix?

Fixing this problem is relatively easy. You can fix it by getting the air filter thoroughly cleaned by an experienced mechanic. Otherwise, just replace the old filter with a new better one. Make it a habit to clean your air filter regularly once you get a new air filter for your ac to avoid such an issue happening again. 

How Much Does A New Air Filter Cost?

The price range of air filers varies according to the quality. Ordinary air filters that are made of paper are quite cheap and costs around $20-$45. These are made to be disposed of after use, so it is not recommended for your car. There are also washable and reusable air filters which cost around $40-$200. These would be more perfect for your car’s ac system. 

4. Antifreeze

Is the cooling system of your car letting out a sweet smell? Then you may have to get your unit checked immediately. The sweet smell is often caused by a toxic liquid of ethylene glycol which is otherwise known as antifreeze. There may be a leak in the cooling system which could be the reason why the smell is coming out of your AC. The leak can come from the heater core, pipe or hose, coolant housing unit, or the radiator.

How To Fix?

You have to get your car checked immediately by your trusted mechanic in such a situation. The smell may be quite good to enjoy, but it is not something to be ignored. If ignored, the leak can increase which can cause serious damage to your car. 


Having to drive your car with pungent smells that are coming from your car’s ac is not at all desirable. This is not a matter that must be ignored either. Identify, detect and find what the smell is and its cause is to remove the smell forever from your air conditioner system. Hope this article will help you through the process!

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