Last Updated: 24.03.2022

An unpleasant odor inside the car is annoying. It can be uncomfortable, especially when you are driving. Not to mention, you are constantly thinking about the potential cause and whether or not it can result in serious damage. 

If you are wondering, why does my car smell like vinegar, we got you! Read on as we walk you through some of the potential causes, and more importantly, the most effective fixes. 

Why Does My Car Smell Like Vinegar? 

When you smell vinegar in your car, look around. It can be because you have spoilt food or any decaying material. Otherwise, it can be a problem with your car’s components, such as the battery, catalytic converter, and filters. Below, we’ll take a closer look at some of the most common suspects. 

Mold and Mildew Buildup

mold and mildew on car seats

The most common culprits for foul odor in your car are mold and mildew. They can result in an unpleasant smell, including one that will remind you of vinegar. Not to mention, they can also lead to respiratory allergies, so you must address them accordingly. 

As your car ages and gets more exposure to elements like moisture and humidity, mold and mildew will be apparent. Bacteria grow in the air conditioning system, especially the evaporator. It will have a pungent smell, which is most apparent when you turn the AC on. 

Keeping your car too long in the garage is a common reason for mold and mildew. The coil and fins become a breeding place for bacteria. Aside from the vinegar-like smell, another common indication of this problem is the frequent AC breakdown. 

Climatic factors are also to blame for mold and mildew. If you are from a location that experiences heavy humidity and rainfall, your car is more prone to getting moldy. To add, poor maintenance can also contribute to the problem. 

Presence of Decaying Material

couple eating inside the car

Mold and mildew are not the only decaying materials that can leave a vinegar-like smell in your car. The same foul odor can be present with a pile of natural decaying material around the AC. Animal or plant matter, for instance, can decompose if you do not remove them immediately. It can turn sour and will be evident when the AC blasts air. 

The stench can also come inside the car, especially if you have decaying food. For those who often eat while inside the car, food crumbs can fall on the floor or the crevices of the seat. Leaving it untouched will result in a decaying odor. 

Old Transmission Fluid

mechanic and dripping old transmission fluid

The transmission fluid is one of the most important liquids for the peak performance of your car. Over time, with exposure to heat, the fluid can break down. It does not only compromise power, but as it goes stale, it can also result in other problems. Among others, it can create a foul vinegar smell. 

This is a problem that is more common in fuel-fed manual vehicles. If you skip a transmission flush, there is a high likelihood that the transmission fluid will leak. You will know when this happens since you will notice the smell of vinegar or rotten egg. 

Battery Leak

car battery with pole corrosion

Your car’s battery has chemicals, including sulfuric acid. They are vital for supplying the power that you need. Nonetheless, with frequent vibrations and damages over time, the battery can leak. The chemicals can spill, which will have the smell of a rotten egg. In some instances, this odor can also be reminiscent of vinegar. 

A common reason for a leaking battery is overcharging. The electrolyte boils, creating steam. It will pool on the surface, which looks like it is sweating. More so, leaks can also happen when you overfill the chambers. Additionally, plate expansion, cracks, and exposure to extreme weather conditions can also contribute to the problem. 

Excessive Condensation

The condensation pan of your car may overfill and leak, which is another reason for having a vinegar smell. This can be a result of the improper functioning of the cooling system. Water can drip on the pan and moisture will form inside the vehicle. 

It is also possible that there is a clog in the condensate pan. The latter catches condensate that forms from the warm air that passes through the evaporating coils. Cracks, corrosion, and blocks in the pan can also lead to excess condensation. 

Faulty Drainage System 

Like in your house, the drainage system in your car can be problematic. The failure to address this immediately will result in having a pool of water, which can eventually smell like vinegar. This is related to how mold and mildew can be present. This is especially common in areas where it often rains, especially if you park your car outside most of the time. 

Most of the drain holes in a car are found at the bottom of the door. The clogs in the hole will prevent water from flowing freely. Instead, it will accumulate at the bottom, which can potentially spill on the floor. As it dries, it can develop a stink that is similar to vinegar. 

Gas Leak 

It is not only the transmission fluid and battery that can leak. The same thing can happen to gas, which is another reason why you might notice a vinegar-like odor. However, this is not just a result of the gas itself. It has methyl mercaptan, which is an additive that can spill into the AC and will smell like vinegar. It is not only repulsive but also dangerous, so make sure to address the problem immediately. 

The longer you wait to fix a gas leak, the more hazardous it becomes. It is especially risky in an enclosed space. If you cannot fix it as you are still driving, at least, open the window. Adequate ventilation will minimize the extent of the problem. 

Broken Catalytic Converter 

A catalytic converter has a catalyst that converts hazardous fumes into safe gases. It is a must-have for minimizing the emissions of your car, which also means that you are minimizing your contributions to air pollution. Like other parts of your car, it can suffer from wear over time. Once it breaks, it will have a sulfur-like smell that is reminiscent of vinegar or rotten eggs. 

Aside from the foul odor, there are other symptoms to watch out for to know if the catalytic converter has a problem. For instance, the check engine light will turn on and your car will also suffer from poor mileage. Not to mention, it will also have inferior performance and rattling sound. 

In case it is clogged, here are the steps you can take to unclog a catalytic converter

Old Fuel Filter 

Because of its small size, a lot of car owners often ignore the fuel filter despite its importance. It is a crucial component of the fuel delivery system. It traps dirt, rust, scale, and other impurities that can mix with the fuel and make it ineffective. It develops problems as time progresses. Among others, one of its effects is having the smell of vinegar.

When the fuel filter is in its peak condition, it assists the catalytic converter in turning hydrogen sulfide into odorless and harmless steam. On the other hand, as it wears out, the fuel filter can result in an influx of sulfur accumulation in the fuel system, which is what contributes to the foul odor. 

Defective AC Components 

The stench often comes from the AC ducts or vents, which often happens when you have issues with the components of your car’s cooling system. From normal wear to dirt accumulation, these parts diminish over time, and if you fail to fix them, they can contribute to rancid odor. 

Among others, one of the parts to look at is the cabin filter since it can trigger mold formation. As a result, the air that goes into the vents will have a foul smell. Burnt compressor and compressor clutch can also be the issue. Find out how to tell if your car has a bad AC compressor

How to Get Rid of the Smell of Vinegar in Your Car 

Many of the solutions are basic and you won’t need to pay a mechanic to do the job. Below are some of the tricks that will help you target the source and remove the pungent odor in your car. 

Remove Mold and Mildew 

As earlier mentioned, mold and mildew are two of the most common reasons for your car smelling like vinegar. One of the best solutions is to vacuum the car for removing loose particles and following it up by sprinkling baking soda. It can also act as a natural air freshener. 

While it might sound odd, you can also use vinegar. It is a powerful disinfectant that can kill mold. Don’t forget to wipe the surfaces and let it air out before using the car. Otherwise, you will end up stuck with the same smell that you are trying to get rid of. 

Maintain the Battery 

Another culprit that we have earlier talked about is a battery leak. Proper battery maintenance will minimize the chances of this happening. One of the most important things to do is to position it securely. If it wobbles a lot, especially if you often drive on rough terrains, it can be more prone to damage. This will increase the likelihood of leaking. 

Inspect the battery regularly. Watch out for leaks, dents, rust, corrosion, and other physical damages. Replacing it when necessary is a must. Otherwise, it will leak. 

Use Natural Odor Removers 

Cleaning your car may not be enough. If the stench persists, you might want to explore using natural odor removers. While you can use air fresheners in aerosol sprays, they may contain harmful chemicals, so it is best to resort to natural but equally effective alternatives instead. 

One of the best for natural odor removal is baking soda. Sprinkle and leave it for a few hours. It will absorb the odor and make your car smell fresh after hours. You can also leave a chunk of charcoal. 

Change the Filters 

From air to fuel filters, any problem with the filtration system in your car can contribute to the pungent vinegar-like smell. Regular cleaning will help prevent dirt and debris deposits. Not to mention, it will also make the cooling system more effective, making you more comfortable throughout your ride. 

Hire a Professional 

If all else fails, then your last resort is to go to a professional car cleaning company. This might be the most expensive solution, but it can also be the most effective. From vacuum to steam, they have the most innovative approaches using state-of-the-art equipment. They have experts who can figure out the root of the problem and make sure that it won’t bother you. 


If you’re wondering why your car smells like vinegar, some of the potential culprits are mold and mildew, decaying matter, stale transmission fluid, battery leak, excessive condensation, and faulty drainage, among other things. Keep your car smelling fresh by paying attention to regular cleaning and maintenance.