Why Your Car AC Smells Musty & What to Do About It

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car ac smells

Sure, it’s great to have a full-blast air conditioner in your car on a hot day. However, that chilly breeze from the AC vents might rapidly become nasty if it’s spewing musty odors! Is it just you, or is there a severe problem with your vehicle?

Your car’s air conditioning system is critical to a comfortable driving experience, particularly throughout the summertime. There is no more superb driving experience than regulating your car’s air conditioner throughout the heat.

However, excessive usage of the vehicle’s air conditioning system can wreak havoc on its system and result in a terrible car smell emanating from the vehicle’s air conditioning. If you’ve ever put on your car’s air conditioning on full blast on a sweltering day and noticed that your car AC smells bad, you’ll understand what we’re talking about here.

These car odors may manifest themselves in various ways, including mildew, musty smell, rotten fruit, smelly socks, to name some – and it may even be associated with nausea and headache. You might not want to go through such an ordeal.

Let’s discuss why this unpleasant car smell originates and how to get mildew smell out of your car.

What Causes Car Odors To Develop?

car smells

If your car’s drainage system is clogged or damaged or you often operate your air conditioning system, the system is prone to remain damp at most times, creating an ideal environment for mold and germs to thrive.

The airflow within your evaporator and the mold growth on the component will convey the bad odor into your automobile through your AC vents. Mildew or mold is the most prevalent cause of unpleasant odors emanating from your car AC system.

Bacteria, mildew, and other undesirable microorganisms might increase as car ages. Whenever your AC system isn’t operated often enough or is operated excessively, this may also promote the development of these bacteria within your AC system and its ventilation system.

The mold that produces odors like to live in your car AC system because it is constantly damp and dark – ideal conditions for mold to thrive. Another cause of the odor coming from your AC vents might be anything carried inside the vehicle, such as food, wet floor mats, children’s messes, cigarettes, sweaty clothes, or pets.

As air is cycled throughout the cabin, particles contributing to the initial odors get trapped within the cabin air filter and accumulate over time. Cigarette smoke, in particular, permeates the inside and is famously challenging to remove.

And it’s not surprising that throughout time, with the smoke smell being recirculated and pushed back through the air from seat cushions and other secondary factors inside the car – it could begin to pile up significantly in your cabin air filter.

How to Remove Unwanted Car Odors

The most effective method of eliminating unwanted odors from your car interior is to clean the whole cabin thoroughly. Foul odors might move from locations such as the ventilation system that blows air throughout the interior of your vehicle.

Replacing the ventilation filters or even spraying an air freshener alone might not solve the issue. Additionally, you must clean your vents to restore the fresh and new car smell; however, how do you accomplish that? Is rinsing and scrubbing sufficient? Generally, this isn’t enough. Consider the following recommendations while tidying the interior of your vehicle.

Vacuum First All Car Surfaces

Vacuum ultimately all inside surfaces, even the door panels, before you proceed on steaming. Utilize a car vacuum that lets detailing to get into cracks, holes, and gaps to remove odor-causing trash, decomposing food, and cigarette ash. And besides, if all causes of odor are not eliminated, odors might soon resurface.

Use Baking Soda

Baking soda is one of the various fantastic substances that works quite well as a deodorizer. And not only is baking soda effective in eliminating smells, but it is also excellent at clearing tough stains and soapy residue. Sprinkle baking soda over your door’s surface, floor mats or carpets, chairs, or anyplace else in your cabin which has an odd stench. Let at least 15 minutes for the baking soda to rest. For persistent odors, such as smoke, pour baking soda over the afflicted areas and leave overnight.

Utilize A Powerful Steam Cleaner

Steaming is by far one of the efficient cleaning methods and deodorizing any interior automobile surface. Commercial-grade steam cleaners are capable of thoroughly cleaning, sanitizing, and protecting every square inch of your vehicle’s cabin.

Steam cleaners operate at high pressure, blasting away dirt, debris, and unwanted tiny particles such as dust, mildew, mold, germs, etc. These devices not only cleanse but also disinfect your vehicle’s interior components, leaving them smelling fresh.

Additionally, steamers are all-in-one equipment. Detailers get a powerful steaming device in addition to a shampooer for cleaning the seats, upholstery leather, and carpet fabric. Also, these industrial steamers have a comprehensive tool kit that enables detailers to access hard-to-reach spots where unpleasant smells tend to lurk.

Detailers often have to use it to remove mildew smells and other unwanted vehicle odors. On the other hand, specific filthy car interiors may require additional consideration with organic spray products. In such instances, you have several different options.

Apply Mild Detergent

One alternative is to combine a moderate conventional detergent with natural ingredients with steaming. Certain commercial detergents for automobiles include additional odor-eliminating compounds that make the vehicle’s cabin feel better.

Always use the mildest spray cleanser that would work since many modern clients choose environmentally friendly cleansing and deodorizing procedures. While removing cigarette or smoke odors from a vehicle, be sure to thoroughly clean its headliner since it absorbs all odors contained within the materials.

Apply Distilled White Vinegar

Rub the surface using distilled white vinegar, a cheap but effective odor neutralizer. Use vinegar sparingly since too much may cause the sour scent to persist for a couple of days up to weeks, particularly with the vehicle windows shut. Always mix vinegar with around 50% water and spray it over the region with the most stench to resolve this problem.

Redo Cleaning

Certain spots may require multiple runs with the steamer and the shampooer to eliminate the odor. Make multiple runs if necessary, as this will ensure that your vehicle detailing task is thorough.

Don’t Forget Your Engine Bay

Occasionally, foul odors may arise from your engine; as a result, it is why your car AC smells bad due to dirt and filth accumulation. These odors could penetrate your cabin via the dash vents. Cleaning your engine using a steam cleaner, degreaser, and freshwater rinse might help prevent the possibility of unpleasant odors landing on interior surfaces. Wipe the entire surface using a microfiber cloth to finalize.

Utilize An Ozone Generator

Consider adding an ozone generator to your armory if you don’t have one. After a thorough cleaning, you might notice a faint chemical odor that can be readily eradicated using an ozone generator application. The ozone cycle typically takes 15 to 30 minutes to accomplish, and the car must be vented with doors open afterward. This last touch ensures that the inside of the automobile is odor-free.

Apply Essential Oils

If you’ve explored all other options and a lingering foul odor persists, a couple of droplets of essential oil could help. Although essential oils will not eliminate odors, they will hide them for extended periods and function as excellent air fresheners.

Essential oils are available in a various scents, including mixes. But, you should be careful that if you employ an excessive amount of aroma, essential oils might become overwhelming. Simply sprinkle a couple of droplets on a cloth and stash it in the back seat or glove compartment.

Some Common Car Odors And Their Causes

Whenever your car emits a bad smell or nauseating odor rather than the recognizable new car smell, you should follow your nose to the origin of the odor. Bad odors might result in costly fixes or health risks and should not be disregarded.


If switching on your AC produces a musty smell, mildew or mold has most likely grown in the system. Excess moisture or water leaks gathers naturally on the cold AC evaporator, which may house mold. By turning the fan on at high speed without turning on the AC, you might dry your evaporator and remove the mildew and odor.


Coolant features a sweet, sugary aroma, and smelling it within a vehicle usually indicates a cooling system or coolant leak. The origins may be obscure. For instance, the leak might be caused by a rusted heat exchanger located behind your dashboard.


Oil may be spilling onto a hot component of your engine or into the exhaust. Additionally, it might be caused by burnt rotors or brake pads— whether due to hard braking, brake pads that do not return when the brake pedal is released, or the emergency brake having left while driving.

Rotten Eggs

Whenever you detect rotten egg odor, the catalytic converter may have failed. A rotten egg odor might result from an emissions system or engine malfunction that caused your converter to overheat.


A burnt rubber smell might indicate a sliding auxiliary drive belt or perhaps a belt being eaten up by a damaged pulley or hose grinding against a running component. Additionally, an overworked clutch plate might emit an odor similar to burnt rubber.


Are your nostrils filled with the smell of burnt toast? This might result from a short circuit within the electrical component or very hot insulation. Electrical smells should be taken seriously since overheated parts and short circuits often cause fires.


It is common for a small amount of gas to be detected whenever a cold engine starts.  If, however, you smell petrol fumes after your engine has warmed up, the fuel cap might be loose, or the EVAP (evaporative emissions control system) — which is designed to collect and recycle gasoline vapors — might be leaking or blocked. Worst-case scenario, gasoline may be leaking from your tank or another component of your fuel system, like the fuel line.


Indeed, our sense of smell is a masterpiece, allowing us to perceive the aroma of anything and sometimes even hazards. Car odors may be pleasant or unpleasant, but with the correct products, proper cleaning, and maintenance, you can eradicate musty odors and prevent mildew and other unwanted odors from lingering or returning!


Will mildew smell go away in the car?

Use an anti-mildew product, enzyme cleaning, or odor absorbers to the surface after it’s totally dry. Additionally, you might pour baking soda over the upholstery and let it sit for a day or two before vacuuming. By that time, the odor should have subsided.

Why does my AC smell weird?

A musty odor signifies bacterial development build-up on your car drain, drip pan, or evaporator coil of your AC. Because the evaporator coil is a darkened and damp region, it is ideal for mildew and mold growth, which results in a musty odor.

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