Why Does My Car Smell Like Vinegar And What Can I Do About It?

Have you ever gotten in your car only to be overwhelmed with a strong vinegar smell the minute you turn it on? At best, it could be an unpleasant smell you have to endure while on your commute. At worst, it’s an indicator of something greater that could be affecting the performance of your AC as well as your health and the health of your passengers.

To fix this issue before it gets worse, let’s take a look at what could be the most common issues causing a strong vinegar odor in your car.

Mold and Mildew Is Usually The Culprit!

There could be a variety of reasons as to why your car smells like vinegar. But the most common reason for a vinegar-like smell is the growth of mold and mildew in the air vents of your air conditioning system, caused by excess moisture.

If the smell of vinegar occurs only when the car’s air conditioner (AC) is on, this is a strong indicator that mold is the culprit. To test this, drive a few blocks without turning on the AC and check whether the sour smell is less noticeable without the air conditioning.

When running, air conditioners can produce a great deal of condensation which leads to water dripping in the unit. That’s because outside air entering your car is moist and warm and must be cooled down by the evaporator coil before circulating cold air through your car.

When moisture accumulates inside the dashboard and fails to dry completely, the damp and humid environment becomes the perfect breeding ground for bacterial growth and mold in the AC unit.

And when unmaintained, what you are inhaling every time you turn on your AC is mold.

Additionally, leaves, dirt, pollen, and other organic materials can accumulate in and around your AC. When these substances decay, they can emit a bad smell similar to vinegar.

Faulty Drainage System = Excessive Moisture

While hot weather and high humidity can lead to the growth of bacteria and mold in a normally functioning car, the presence of mold could signal a fault in the car.

That’s because a car already has a component designed to remove excessive condensation – the drain tube.

If the drainage system is not functioning properly, water drippings will overflow the condensate drain line and the air conditioner will spread moisture throughout the system and even the interior cabin of the car.

Don’t Rule Out A Dirty Cabin filter

It may also be that your cabin air filter is in need of cleaning or replacement.

Air filters block out pollution, car exhaust fumes, dust, dirt, and a variety of other nasty toxins that come into the interior through the heating, ventilation and air-conditioning system.

A dirty or clogged air filter will fail to do its job properly and contribute to lingering smells and health concerns.

Less Likely Causes Of A Vinegary Smell

While the presence of mold is the most common reason for a vinegary smell in the car, there could be other causes.

A battery acid leak is a common source of an unpleasant odor in the car. While the sulfur fumes it creates is normally described as a rotten egg smell, it could be perceived as vinegary.

The car’s electric air conditioner motor could also be emitting ozone. This can have a sour smell, even more so when combined with any mold that is already present.

Finally, it could just be general filth and stains on upholstery. This could be from sweat or eating and spilling drinks in the car, for example. Of course, this should be fairly obvious to the owner, but it’s worth checking hidden areas to be sure.

The Dangers of untreated mold and bacteria infestation

The presence of mold, mildew, and decaying organic matter can certainly lead to a persistent and annoying sour and musty smell, but the effects of mold can be especially concerning to your health.

People exposed to even a small amount of mold can experience coughing, stuffy nose, itchy eyes, sore throat, fatigue, and skin irritation. Prolonged exposure could worsen asthma and allergies and lead to serious lung infections with people with preexisting immune disorders and lung conditions.

Without treating the issue, the smell of vinegar emanating from your car can detrimentally affect your car’s performance as well as your health. So, what can you do about it today?

How can you eliminate the smell of vinegar in your car?

Now that we’ve discussed some of the causes of a persistent vinegar smell, it’s time to turn to what you can do about it. Typically, mold growth does not happen overnight. Long term and quality maintenance of your car will be the best preventative care for your car.

Do the following:

1. Clean out the AC vents

Grab a cleaning brush, and deeply scrub your AC vents. Use an anti-bacterial spray to deep clean the ducts. Some people may recommend Lysol or another antiseptic product. However, these products are more likely to mask the bad smells than prevent them from forming. Consider buying an AC interior cleaner that has the cyclodextrin enzymes that will actually neutralize and eliminate the source of the problem.

2. Maintain excellent AC habits

To avoid excess condensation, take some small steps each time you use your AC. Before turning your car’s engine off, turn off the AC, but leave the fan to blow for a few minutes. This step will help the AC system dry out thus preventing further condensation from accumulating and therefore reducing mold growth.

Furthermore, when the AC is in use, avoid using the recirculate setting too often and avoid using the AC at the highest setting as both of these will only exacerbate the issue of too much condensation. The fresh air mode, which uses air from outside the vehicle, will be more efficient in maintaining a clean and nontoxic environment in your car.

3. Replace the cabin air filter

Your cabin air filter is one of the few components of your car that is responsible for maintaining the air quality of your car. When it fails to do its job, old and dirty air filters can impede airflow of the AC. This causes clogs and helps moisture to remain inside and cause the odor. Make sure to clean and replace filters regularly. Always refer to manufacturer recommendations when cleaning or replacing your car’s air filters.

4. Regularly clean your car

From dust and dirt to fast food crumbs and pet hair, your car more so than any other space can become a dumping ground for smelly and unpleasant debris. While it may be impossible to catch every last accident, it is especially important to clean up any liquid spills. Since mold thrives on moisture, quickly and thoroughly cleaning any kind of spill that occurs in your car is essential to maintaining a clean and dry and, therefore, mold-free environment. Beyond catching minor spills, take it a step further and schedule time on your calendar to deep clean your car. Shampoo the mats, use baking soda, vacuum between the seats, and scrub the interiors. These steps will ensure a clean and hygienic area and repel the nasty odors.

5. Consult an expert

If you have followed the above tips and considerations, and the smell of vinegar still persists, your best bet is to take your car to a repair shop. More complicated issues, like a damaged drain tube, battery leak or ozone emissions are best left to a licensed mechanic who can rule out causes and eliminate the guess work to diagnose and resolve the problem.


Unless you’ve recently spilled a gallon of it while on your way back from the grocery store, there’s no reason that your car should smell like vinegar.

As we’ve learned, the smell of vinegar could mean a variety of things: a poorly utilized AC system, the presence of organic matter that has no place being in your car, an air filter in need of replacement, and more.

Take our recommended steps to investigate the cause of the bad odor and get your car back in tip top shape!