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Why Do Car AC Smells Like Dead Animal? Causes and Solutions

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Car AC Smells Like Dead Animal

Any foul smell in a car can make the whole driving experience unbearable. The worst odor is the smell of a dead animal which is hard to diagnose and even harder to get rid of.

But why does a car ac smell like a dead animal? Most times, there is a dead animal in your vehicle’s air conditioning system. Small animals can find their way into the car for comfort or for food and later be trapped inside and die. Mice and rats are among the rodents capable of fitting in the Ac system. Also, mold and mildew are known to cause the dead animal smell.

So, having a stinky car can be challenging, especially if you don’t know the source. Read on to learn the possible causes of the smell and how to clear it from the air conditioning system.

Why Does Car AC Smell Like a Dead animal?

A dead animal smell in the Ac system is common in vehicles parked for a long time. This odor is like that of a carcass, but sometimes people describe it as that of rotten eggs.

Car AC Smells Like Dead Animal

The smell can have various causes, including

1. Dead animal

A dead animal is often the cause of the smell from the air conditioning system. Small animals like mice, rats, squirrels, and possums are known to get into vehicles for warmth and food.

If you leave foodstuffs in the car, they can find their way into the car and then to the Ac system. Most times, the mice will get into the ductwork or cabin air filter, where they chew and use the filter as a nest.

For one reason or the other, the small animal can be trapped inside and die there. The animals can also give birth in the car, and the babies die, resulting in the smell.

Why Does Car AC Smell Like a Dead animal

2. Mold and Mildew

Mold can be another cause for the foul odor from your car’s air conditioning system. The smell is musty but can get worse, like a carcass, if not dealt with soon.

Mold grows due to moisture in your vehicle, which is common in the evaporator and air conditioning duct. Most of the time, these parts are warm, humid, and moist. And that makes them a perfect spot for mold to grow.

Mold and Mildew

A contaminated catalytic converter can also be the cause of the foul smell. However, the catalytic converter smell is more like that of a rotten egg. Thus, the above causes must be diagnosed and solved as soon as they’re noticed. 

How to Identify the source and clean it?

The dead animal can bring insects and cause leakages if not discarded on time. Mold can also cause allergies and asthma in people prone to allergies. Follow these steps to identify the source and take action accordingly. 

How to Identify the source and clean it

Step 1. Check the air filter, often located in the glove compartment, because rodents damage it to make a nest. 

Step 2. If there is a dead rodent in your air filter, wear some gloves before handling it. 

Most people with the dead animal smell problem on Reddit found a dead animal in the cabin air filter. Also, mice can crawl into the blower assembly in the dash and die. 

Step 3. Check the cabin filter and the blower assembly before proceeding to other parts.

Step 4. Take the blower motor out and use a shop VAC to suck the debris out. You can also call an expert to assist in tracing and removing the animal.

Step 5. If you suspect the cause is the mold, use a disinfectant spray to clean through the car’s plenum. This part is below the wipers and contains vents where the air goes through.

How Do You Get Rid Of the Dead Animal Smell?

How Do You Get Rid Of the Dead Animal Smell

Removing the dead animal doesn’t completely solve the problem and you should clean more. If the air filter is affected, it must be replaced with a new one. However, you can try DIY by following up the steps below. 

Step 1. You can use cleaners or homemade solutions, like vinegar and water to clean. 

Step 2. Spray the cleaner on the air conditioning system, especially on the affected parts. Some professionals suggest using a deodorizing agent first, followed by antimicrobial treatment.

Step 3. After applying the cleaning solution, turn on the heater and roll down the windows for a few minutes. The fresh air and warmth should clear any remaining moisture and smell.

Step 4. This solution is not permanent and for some cars, the drivers must spray again after a few months. Mercedes cars had that problem which led to the court granting HVAC settlements to reimburse people and help with repairs.  

Tips to Avoid Dead animal Smell in Your AC system

Tips to Avoid Dead animal Smell in Your AC system

Diagnosing and fixing a car with a dead animal odor is costly and takes time. Luckily, you can save yourself from this ordeal using the tips shared below.

Park Inside

Avoid parking your car in the open, especially if it will remain there for some time. Rodents can get in from under to seek shelter and warmth.

Park Inside Your Car

Avoid Food Stuff

Avoid parking near a food source, including pet food, as rodents can hoard the food in your car. Also, avoid leaving foodstuffs inside the vehicle because they also attract animals.

Dry The Car

Turn off the AC minutes before parking the car to give the evaporator plenum time to dry out. Getting rid of moisture discourages mold from growing.

Use Bait

Place bait under the car when parking for some time to discourage or trap rodents.                                                                                           

Air Out The Car

Park the car under direct sunlight with doors open after every few days to evaporate moisture. This practice is necessary during days when it’s humid or in winter. 

If you’re dealing with a dead animal smell coming from your car’s AC, you may also be interested in our article on car air conditioner smells like chemicals which covers other possible causes of bad odors from your car’s AC system. Additionally, if you’re experiencing a musty or mildew-like smell after rain, you might want to check out our article on car smells like mildew after rain to learn more about the potential causes and solutions.


Following are some frequently asked questions you can take a look at for further knowledge on this issue.

Q: How much does it Cost to Fix a Car that Smells Like Dead Animals?

Diagnosis and repairing an air-con system with a dead animal smell costs between $200 and $500 in various repair shops. However, if you diagnose and fix the problem yourself, it will cost you much less.

Q: Can Vinegar and Lime Get Rid of the Dead Animal smell?

Yes. Vinegar has a strong smell and if used to clean or placed near the affected area, it can remove the odor. Lime can also absorb the smell when used in a contaminated area.

Q: Can a Dead Animal Smell Cause a Health Issue?

No. Other than making you feel nauseous, the smell of a dead rodent cannot make you sick. However, if the smell is related to mold, it can trigger allergies in some people.


The interior smell of the car matters, a reason people use air fresheners to enhance it. However, sometimes this smell is compromised by other foul odors, including the dead animal smell. Dead rodents and mold are among the common causes of foul odor.

Diagnosing and fixing the problem can cause you time and money. Though you can do it on your own, it’s often better to be guided by a professional. Also, by observing the tips in the article, you can avoid this problem.

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