Informational Guide

Why Does My Car Smell Like Vinegar?

Why does my car smell like vinegar? In this guide, we discuss common causes of this smell in cars & how to get rid of it for good.

Very few people enjoy the smell of vinegar, especially in a car. That’s why you might be trying to figure out - why does my car smell like vinegar?  

In this guide, we help you hunt down the cause of the vinegar smell and get rid of it once and for all.  

1. Excessive Condensation 

Condensation can occur anywhere in the vehicle where water is running, especially with the air conditioning system. If a drain is clogged or condensation occurs, you might also notice a faint vinegar smell.  

2. Bacteria Grown In the Heater Box 

Why does my car AC smell like vinegar? It could be the growth of bacteria occurring in the system’s heater box. With condensation building up in the system, the equipment is always damp, creating a superior breeding ground for bacteria.  

3. Defective AC Components 

Why does my car aircon smell like vinegar? If water has been sitting in the AC components, they might have gone bad. Otherwise, a burning plastic smell indicates an electrical problem that should also be addressed immediately.  

4. Moldy Evaporator Coil and Fins 

Why does my car air smell like vinegar? If you aren't using the AC system at all, many of the moving parts sit dormant. As dust, dirt, and contaminants build up, mold can start to grow on the fins and coils of the evaporator. Not only can this create a vinegar smell, but it can also lead to a breakdown of the AC system.  

5. Leaking Battery Acid

If the battery is leaking acid, the smell can come through the air conditioning vents into the cabin of your vehicle. Not only is this annoying, but the leaking battery can be dangerous, so you want to deal with the issue right away.  

6. Dirty or Clogged Air Filter 

When the cabin air filter becomes dirty and soiled, you end up with a musty and dingy smell in the vehicle. Replacing the cabin air filter should be part of a regular automotive tune-up. However, some can be cleaned out, but for the price, it really isn’t worth it.  

7. Dingy Air Vents Or Ductwork 

Mold growth isn’t going to occur overnight, but it does happen. As the mildew builds in the air vents and ductwork, you are going to smell it in the cabin. You might notice the smell more prevalent when you first turn on the air conditioning system after it has been sitting.  

8. Gas Leak 

Some fuels can contain methyl mercaptan. This likely has no relevance to you unless there is a fuel leak. As the gas leaks, the smell of this additive can infiltrate the air, creating a vinegar or skunk-like smell. Even if you could deal with the smell, you should never ignore the dangers of a gas leak.  

9. Broken Catalytic Converter 

If the car has a weird odor that is reminiscent of vinegar but slightly different, it could be due to a faulty catalytic converter. There is a chemical reaction occurring within this vital part, so when it is defective, you will start to smell rotten eggs and other noxious fumes.  

10. Faulty Fuel Pressure Sensor 

The fuel pressure sensor is in charge of regulating fuel use to prevent the catalytic converter from getting clogged and overheating. When the sensor fails, byproducts can’t be processed correctly, leaving behind a rotten egg or vinegar-type smell.  

11. Organic Material Build-Up 

If you have been off-road, there could be stuck-on debris and dirt that is rotting on the vehicle. Otherwise, you might find a dead animal, such as a mouse, decomposing in the system. As the animal continues to rot, the smell might lessen, but you should remove the carcass as soon as you can.  

12. Worn Fuel Filter 

The fuel filter keeps dirt and debris from infiltrating the system. When it becomes clogged, it can no longer do its job, which puts strain on the entire fuel system. As sulfur deposits built up in the catalytic converter, you might notice an odd smell.  

13. Old Transmission Fluid 

Your transmission fluid needs to be regularly flushed to ensure it remains in good condition. No matter what kind of transmission you have, stale fluid can lead to a flurry of smells. If you ignore regular transmission maintenance, you may end up needing a new one in the future.  

14. Ozone Emitting Electric Motor 

As cars continue to become greener, there are more electric-powered models on the road. However, all electric motors that require outside air to be used can bring the ozone into the cabin, which sometimes produces a vinegary smell.  

Man Looking Under Car Hood

How Do I Get The Vinegar Smell Out Of My Car? 

Considering the vinegar smell is likely caused by some form of mold or mildew, here are the steps you need to take. 

  1. 1
    Clean out the vehicle. Learn how to detail a vehicle and clean the car windows for a fresh start.
  2. 2
    Get rid of moisture in the car. When you are done running the air, allow the fan to run for another mile to remove the moisture. You can also add a car dehumidifier to get rid of excessive moisture.  
  3. 3
    Replace the cabin air filter. These only cost a few dollars and are simple to change. 
  4. 4
    Use a car vent cleaning kit to remove dirt and debris from the system.  
man washing a car dashboard

Fixing The Issue Permanently: What Should You Do? 

If you are doing everything you can to reduce the smell, but it keeps coming back, there could be something mechanically wrong with your vehicle. Try and troubleshoot some of the ideas we gave you or take your car to an auto mechanic for a complete diagnostic workup.  

Once the issue is discovered and repaired, you should no longer have to deal with that noxious vinegar smell.  

People Also Ask (FAQs)

How do dealers make used cars smell new? 

The new car smell is always there but becomes obscured by mold, pets, stinky feet, spilled drinks, and bad breath. The trick to making it smell good again is to get rid of all the dingy smells with degreasers, ArmorAll, and Windex. After it's been parked in the sun for a few days, the new car smell returns.  

What is the best odor eliminator for cars? 

The Zero Odor Multi-Purpose Household Odor Eliminator is a popular choice, but other people fall back on using the Chemical Guys New Car Scent as a fall-back option.  

Why does my car have a chemical smell? 

A chemical smell can be caused by a seeping heating system or an antifreeze leak. You don't want to expose yourself to chemical smells and leaks, or you could face larger health issues.  

What does a coolant leak smell like

Antifreeze contains a distinct sweet smell. Some people compare it with maple syrup, while others say it smells like sweet fruit or candy. A coolant leak should always be dealt with promptly.  

Why does my AC smell when I first turn it on? 

If the AC system has been dormant for a few days or longer, dirt and mildew might have built up in the vents or hoses. Running it for a few minutes might resolve the problem, or you might need to replace defective parts.  


Why does my car smell like vinegar? In many cases, it’s nothing severe, but you should always have it looked at if you can’t resolve the problem on your own. Prompt attention today might save you from a hefty repair bill later.