Are you noticing a weird smell in your car? And does that smell appear out of nowhere when you turn on the AC? You do not need to be a rocket scientist to figure out, that the weird smell is coming from the AC.
If you are asking the question ‘ why does my car AC smell?’, there are actually a lot of potential causes. And the smell might vary from cause to cause.
If you do not know this already, your car doesn’t generate cold air or warm air. On a hot summer day, if you reduce the temperature of your AC, the system takes the atmospheric air and takes all the moisture out of it.
The AC coils inside, remove the moisture as well as the heat and send cold air into the cabin.
On the other hand, if you crank up the heat in winter, then the AC cannot take the air outside and do the process that is mentioned above. But again, it does take the air from the environment.
To heat it up, the AC uses the heat generated by the engine. And thus, hot air is pumped into the cabin.
But it is not the heater that causes your AC to smell. If you are wondering why does my car AC smell, it mainly happens when you are trying to drop the temperature inside the cabin.
As the air inside your AC unit is colder, it can cause the surrounding air to condense. Therefore, the stagnant water could cause havoc inside the unit. Another component is the drain pipe.
If the water doesn’t find its way through the drain pipe and out of your AC, it could also cause bad smells. Ultimately, every single component in your AC system should work in sync to keep the AC in your functioning.
And whenever a component fails, you might notice the result as bad smells coming through the vents.
There are different types of smells that you can encounter. If you are asking the question, why does my car AC smell, you need to find a solution to resolve the problem.
Correctly identifying the type of smell emitted from your car is crucial when it comes to fixing the problem. Depending on the smell, you could determine the cause of the smell and deal with it accordingly.
We don’t have to work hard to explain to you how rotten eggs smell. It is a pungent smell, that you will surely notice. If you are looking for a more scientific description of the smell, it smells like hydrogen sulfide. Actually, hydrogen sulfide is also present in rotten eggs.
Usually, sulfur is found in decomposing biomatter. So, it is not only present in rotten eggs. You will find it in dead animals, rotten food, sewers, etc…
You might be wondering, how is this connected to my car. Don’t worry, there are no dead animals inside your dash. Sulfur is present in car batteries as well as the gas you pump. This sulfur turns into hydrogen sulfide and smells like rotten eggs.
There can be many reasons why your AC might smell like rotten eggs. Most of the cases revolve around the battery, gas, and exhaust system.
The prime suspect would be a battery leak. Every car contains a battery. So this can happen to any car. The battery contains lead and battery acid. Battery acid is actually sulfuric acid. This acid produces a chemical reaction in your battery which produces electricity.
If your battery is damaged, it will start to leak contents from the inside. This includes the sulfuric acid in it. This could smell like rotten eggs.
This is smell caused by fuel is rare. If your fuel contains a higher concentration of sulfur when it ignites it will produce a rotten eggs smell. As long as you do not get your fuel pumped in shady places, you should be fine.
Another reason could be the catalytic converter. The catalytic converter is supposed to remove harmful particles exiting your exhaust system. A busted catalytic converter will not be able to keep up with the task. So you would start to smell some weird smells inside your cabin.
Again, this is also not a smell that needs to be explained. Burning rubber smell is one of the worst things you could run into. First off, you have to understand the health risks that come with inhaling burning rubber.
Keep in mind the burning rubber smell is actually caused by burning rubber, and not imitated by another compound.
Inhaling burnt rubber poses a serious risk for your safety as it could cause cancer. So you should not continue to inhale the air in your cabin if it smells like burning rubber.
As you might have already figured out, it is caused when rubber components in your engine ignite. But do you know that burning motor oil could also emit a similar odor?
Though different motor oil emits different smells when they burn, there is a good chance for them to smell like burning rubber. This is more evident in synthetic engine oils.
The best-case scenario is when it is caused by melting rubber. There aren’t many sources of rubber in your engine. But almost all the hoses in your engine are made out of material that is part rubber. So, a burning hose could emit this smell.
Another piece of rubber in your engine is the drive belt. This could also melt when your engine overheats. Other than the fact that it emits a burning rubber smell, there is a risk that it might snap as you are driving.
One of the causes would be motor oil finding its way into the ignition chamber. There are many ways that it could find its way inside the ignition chamber. Usually, it is by worn seals or a blown head gasket. Either way, you have a huge repair on your hands.
This problem is directly associated with the AC unit in your car. You might notice that your AC smells like a sweaty gym shirt that has been in your bag for a while.
So, why does your AC smell like sweat? Have you ever wondered why sweat smells so pungent? It is because of the mold and bacteria that are in it. The reason why your AC smell that way is also due to the same reason. It is also caused by fungus buildup in your system.
Your AC provides a perfect environment for microorganisms to build up. When left unchecked and uncleaned, microorganisms can form inside your AC. This will not only smell unpleasant, but it is also hazardous to your health.
This is often caused because your air intake is filthy. Dirt and debris could build up along your intake vents. There is no way to stop this. So you need to check it regularly and clean it if necessary.
If the debris sits for a long period, it will trap moisture. This provides the perfect environment for bacteria and fungus. All kinds of microorganisms, germs, and mold can originate in damp wet places.
A clogged AC drain hole could also be the reason. When the AC cools, it condenses the water vapor surrounding the area.
This condensed water is sent out of the car through the AC drain hole. This is the water that you observe dripping under your car when the car is running and the AC is working.
If you do not see water dripping under your car when your car is running, that could indicate that your AC drain hole is clogged. When this happens, the water that condenses cannot exist in the system. So it could be lodged in some part of your car.
Again, this would create a dark and damp space ideal for microorganisms. This will also emit a sweaty or moldy smell from your AC.
Obviously, exhaust gases are not supposed to enter your cabin. Air pollution is one of the rising issues we as humans face globally. No matter where you live, you probably have experienced breathing in polluted air.
Though you might not have directly smelled the gases that exit through your exhaust pipes, it basically smells like smoke. These exhaust gases play a major role in air pollution. So if you’ve inhaled polluted air in a crowded city, that is how this smells.
The AC unit does not run is powered by the engine. So you might wonder why does your AC smell like exhaust fumes. The AC units use a few different types of fluids. When these fluids are heated, they emit a smell similar to the smell of exhaust gases.
The fluid that causes this smell is the refrigerant. Sometimes these fluids tend to give out a sweet smell rather than an exhaust smell. So if your AC blows air that is sweet or smells like maple syrup, you have the exact same cause.
So, why do these liquids heat up? Is it normal? No, it is not normal for your AC to smell like exhaust gases. If your AC smells like exhaust gases, it is most likely caused by a leaking refrigerant line.
The refrigerant is the fluid that cools down the air temperature. Thus refrigerant is necessary for your AC to blow cold air. So, when your refrigerant is leaking, you might also notice that your AC has also lost its ability to cool the cabin efficiently.
Some old cars use a refrigerant called Freon. This is a chlorofluorocarbon. This is a highly threatening substance to the environment and it is being slowly phased out of modern cars.
Freon is capable of absorbing the heat from the air, thus it is one of the most effective substances that can be used in cooling. This is one of the reasons that this was widely used in the past. This is the same substance that was used in refrigerators in the past.
Rather than calling this a smell, it is best to consider this as your AC blowing dust. Chocking dust coming through your vents can be irritating. The AC is opposed to making your drive more comfortable. When it starts blowing dust at you, it will make driving much harder.
As you might have already figured out, this is caused by dust. If your car has bitting sitting around for a long time, the ventilation system could have accumulated some dust. So once you turn the AC on, the dust will be blown out. If this were the case, it should settle after a while.
Another cause could be the air filter. Generally, your air filter lasts around 10,000 to 15,000 miles. So you need to replace your air filter at least every 15,000 miles. If it is not replaced, it won’t be able to filter the dust particles that are blown by the AC.
This is a tough question to answer. Almost all the smells that you could encounter are bad for your health or the environment. But this is not a serious enough issue for you to pull over and call a tow truck.
Usually, when the smell is bad the first thing to do is to switch off the AC. Open up your windows. This will allow atmospheric air to circulate the cabin.
Though trace amounts of those toxic gases might enter the cabin, as long as your windows are rolled down, that ventilation should be enough.
You cannot live without the AC forever. If you are asking the question, why does my car AC smell, now you know that it is caused by a piece of faulty equipment in your car.
And even though you might be able to drive without an AC, something else in your car is also malfunctioning. So you need to get your car checked and fixed soon.
But if you smell burning rubber when you turn on the AC, the situation is completely different. Obviously, something in your car is burning. Thus it is just a matter of time before you run into a major hurdle. So, you need to visit a professional to solve the issue.
Because of health-related issues, you should not use the AC if you smell unusual odors. You cannot accurately identify the substance that is causing the smell. It is not worth risking your lungs just to get some cold air.
If you assessed the causes of all these different types of smells, you might have noticed that through proper maintenance, you can avoid a lot of these problems.
Maintaining your AC system properly will ensure that you do not run into unwanted stenches, and keep your AC working efficiently.
So how do you maintain your AC? The first thing to do is to regularly change the air filter. It is a good practice to change your air filter every 6 months. A clogged air filter will put extra strain on your blowers.
This will reduce its life span as well as efficiency. Even if you do not replace it, at least clean it every 6 months.
You can get rid of a lot of moisture by running the defrost system in your AC unit. Keep it on for about 15 minutes regularly. This will reduce the chances of the build-up of mold.
Make sure that the coolant is circulating at the appropriate pressure. The coolant runs through hoses. Leaks in these hoses could cause the coolant to run out. Without coolant, you cannot expect your AC to function.
The hoses could also get clogged. This will increase the pressure of the coolant which is also bad.
Check the state of the evaporation coil during routine maintenance. Replace damaged evaporator coils, this will ensure that your AC unit operates efficiently.
Finally, if you suspect that your AC is not working properly, check the evaporator fins. You might notice that the condenser fins are bent. Straighten those out so that your AC works properly.
By properly maintaining your AC, you could drastically reduce the chances of running into issues. This means you won’t have to wonder, why does my car AC smell?
Without understanding the type of smell or the cause, there is not a lot you can do. The easiest way to deal with a smelly AC is to take your car to a mechanic.
But this would be costly. Without knowing what component is damaged, you won’t be able to estimate the repair costs either. There are a few things that you can try out yourself before going further.
First, remove the air filter. Clean the dirt away and wash it with soapy water. This would solve the issue if it is caused by a dirty air filter. If the filter is damaged, you should replace it.
If the cause moisture, you need to dry the evaporator core. Keep the AC on for about an hour, it should dry it out. If the issue is at its early stage, this would work.
The most probable cause is the lack of refrigerant. Maybe there is a leak that is causing your refrigerant to drain out. Without refrigerant, your AC will not be able to blow cold air.
Another possible cause is a dirty air filter. If the air filter clogs up the airflow, it will lessen the cooling capability of the AC.
Ever since scientists found out that Freon is causing the ozone layer to deplete, the use of Freon in cars has been reduced. But it is still present and used in older cars.
Sulfuric acid is a highly corrosive chemical. It could cause extreme pores and skin burns. It can irritate the nostrils and throat and can cause irreversible damage to the respiratory system. It would also irritate the eyes.
If you are smelling rotten eggs when you turn on the AC, there is a good chance that it is caused by battery acid or sulfuric acid leak.
If there is moisture present, it could allow mold to grow inside. This fungus can produce mycotoxins. Mycotoxins contain ammonium. Urine also happens to contain ammonium. So you will smell a similar smell to urine due to the ammonium present in the mycotoxins that are blown through the vents.
Buy a disinfectant spray that removes mold. Now get inside the car and switch off the AC. Now all you have to do is spray the disinfectant spray through every vent in your car. This includes the vent in your dash, the vents near your feet, and the vents in the back seat.
There are many types of smells that you can run into when your AC unit is malfunctioning. Different smells are caused by different errors in the system. So by noticing the exact type of smell you are encountering, you can choose your next step accordingly.
If you are asking, why does my car AC smell, chances are you are smelling trouble. Almost all smells are bad for your car. Further, some are hazardous to your health as well as the environment.
Due to these reasons, when you notice an unusual smell from your AC, you should diagnose and find the cause immediately. And once you find the cause, you need to get it fixed without further damaging your car.
Most issues occur due to the lack of maintenance. So, the best way to avoid these problems is to spend some time properly maintaining your AC unit.
