Car AC Smells Like Poop – 100% Get Rid Of Smell – 2024

An air conditioner in my car has been emitting an unpleasant odor resembling excrement, making long drives uncomfortable and embarrassing for me and my passengers. This raises the question: Why does my AC smell like poop in my car?

If your drain line is damaged or you frequently use your AC system, the unit is likely to stay damp all the time, which creates a breeding ground for mold and bacteriaThe air that passes through the evaporator and the units’ mold build-up will carry the foul smell inside of your car through your dash vents,

In this post, we’ll delve into the unpleasant issue of bad smell in car air conditioner and offer practical fixes to eliminate the odor, ensuring a more comfortable and pleasant driving experience for you and your passengers.

Why Does The Air Conditioner In My Car Smell Like Manure or Poop?

Having experienced the unpleasant odor firsthand, I delved into investigating the root causes behind why my car’s air conditioner emits a foul smell reminiscent of manure or poop. After thorough research and personal experience, I uncovered several factors that contribute to this issue.

Also Read: Why Does My Car AC Only Work In The Morning

1. Clogged Drain Line:

Why does the air smell like poop? The AC drain line takes this moisture outside the car and lets it go. But if dirt, leaves, or other things get stuck in the drain line, it can stop the condensation from moving out of the AC unit.

Clogged Drain Line
source:Kia Soul Forums

As a result, moisture may build up, providing the perfect conditions for bacteria, fungi, and other germs to thrive and emit a poop-like scent.

2. Garbage Or Food:

Why does my car ac smells like manure? If trash or food that has gone bad has been left in the car, it can smell bad. It can happen if garbage or food is not thrown away correctly and is left to rot in a warm, tight space.

Also Read: Is It Ok To Run Car AC While Parked

3. Sewage Leak:

Why car ac smells like sewage? A sewage leak is one of the most frequent causes of a car’s air conditioner smelling like manure or poop. It can happen if your sewer line is clogged or the seals around your pipes are broken. Because of this, sewage fumes can leak into your car and make it smell bad.

 Sewage Leak
source:AC leaks water

4. Mould Or Mildew:

Why does my ac smell like poop? The culprit: mold. Mold or mildew growing in your car’s air conditioning system can make it smell musty and bad, like poop. It can occur when the AC system has too much moisture, making it the ideal environment for mold growth.

The mold smell inside your car is carried through your dash vents by the air passing through the evaporator, which has accumulated mold build-up. Mold is frequently responsible for the unpleasant odors emanating from your car’s AC system.

5. Chemicals Or Vapours:

Some materials or parts of your car can give off chemicals or fumes that can make the inside of your car smell bad. For example, the glue used in car seats or the plastic parts of the dashboard can give off strong, unpleasant smells.

Chemicals Or Vapours
source:car problems

Also Read: Can Air Conditioning Affect Transmission

6. Dirty Air Vents:

Air vent smells like poop? Over time, dirt, dust, and other particles can build up in your car’s air vents. It can make your AC smell musty or bad when you turn it on.

7. Stale Air:

The air inside your car could be stale and stinky if you haven’t used the air conditioner in a while. It may occur if the car is left standing for an extended period or if the air conditioner isn’t utilized often.

Stale Air
source:ultra fresh

How Do I Fix Car AC Smells Like Poop?

After encountering the unpleasant odor emanating from my car’s air conditioner, I embarked on a mission to eliminate the foul smell. Drawing from personal experience and insights gathered from various sources, here are some effective solutions to address the issue:

1. Unclogged Drain Line:

How to remove smell from car ac? You need to clear out the debris from the AC drain line. It can do this with a wet/dry cleaner or a can of compressed air. You can also take your car to a skilled mechanic who can clean and flush the drain line for the air conditioner.

Unclogged Drain Line
source:hydraulic suspension

Moreover, you should also replace your cabin air filter, which can get dirty and add to the smell.

Also Read: Can I Sleep In My Car With The AC Running

2. Clean The Car:

if your car air conditioner smells like garbage, To eliminate the smell, eliminate any trash or food that might be causing it. The remainder of the inside of the automobile, including the seats, carpets, and air vents, should be cleaned. You can also hide the smell with an odor-remover spray or an air freshener.

Clean The Car

To keep this from happening again, throw away trash and food correctly and often clean the car’s interior.

3. Repair Sewage Leak:

You should call a plumber immediately if there is a sewage leak. They can find out where the leak comes from and fix or replace the broken pipes. Also, you can avoid sewage leaks in the future by getting rid of the trash correctly and keeping your car’s lines and sewage system in good shape.

4. Get Rid Of Mould Or Mildew:

Car ac smells like feet? To get rid of mold or mildew, a professional should clean the AC system in your car. It can mean removing and cleaning the evaporator core, a part of the air conditioner that can collect dust and wetness. Changing your car’s cabin air filter helps prevent mold and mildew from growing.

Get Rid Of Mould Or Mildew
source:fortador USA

Also Read: White Smoke From Car AC Vent

5. Clean Air vents:

You can use a special cleaner or a vacuum with a brush attachment to clean the air vents to eliminate the smell. You can also have a professional clean your car’s AC system, which can help eliminate any dirt and odor.

Clean Air vents

7. Remove Stale Air Smell:

To get rid of the musty odor in the car, turn on the air conditioner and prop open the windows for a while. It can assist in circulating clean air and eliminating odor. Frequently running the air conditioner in your car can also prevent the air from becoming too stale.

Remove Stale Air Smell

Car Air Conditioner Smells Strange:

When dust and debris accumulate in the under-hood air intake, moisture can become trapped on the evaporator unit and within the evaporator case.

This trapped moisture provides an ideal environment for mold and germs to proliferate. Consequently, when you activate the AC, you may detect a musty odor emanating from the system.

Also Read: Car Temperature Gauge Stays On Cold And AC Not Working

Why Does My Car Air Conditioner Smell Like Chemicals?

A pungent chemical smell with hints of moldiness often indicates a refrigerant leak from the AC evaporator. If you notice the blower fan operating loudly but little to no airflow from the vents, it’s likely that your car’s refrigerant has leaked onto the evaporator fins.

Why Does My Ac Smell Like Sewer?

The scent of raw sewage emanating from an AC vent is concerning and may suggest a backed-up sewer line or a ruptured sewer vent pipe near the ductwork. Even a small amount of methane from the backup can permeate your surroundings with an unpleasant odor.

Quick Steps To Get Rid Of Bad AC Smell:

  1. Turn off the AC 2-5 minutes before turning off your vehicle while keeping the fan on. This allows the entire AC unit to dry thoroughly after each use.
  2. Regularly clean or replace your AC filters. Dirty air filters reduce airflow through the AC system, which can trap moisture inside. Be sure to follow the manufacturer’s recommendations for filter replacement.
  3. Use an antiseptic spray in the exterior air vents, where your car draws in outside air. Ensure that your AC is set to the mode that pulls in air from the outside. This allows the spray to enter the ventilation system and effectively combat mold and bacteria.

Also Read: AC Blows Warm At Highway Speeds

How Ultra-Fresh Can Help To Prevent Bad AC Smell:

  • Ultra-Fresh is an antimicrobial agent incorporated into various components of the car’s AC system, such as foam, filters, rubber, and adhesives.
  • It inhibits mold growth, preventing musty odors from developing in the first place.
  • This technology is used by automotive and aerospace manufacturers to address mold and odor problems in vehicle AC systems.

1. How Can I Tell If My Car’s AC Drain Line Is Clogged?

If your car’s AC drain line is stuck, you can check to see if water is building up on the floor mat on the passenger side. A musty smell or a wet couch are also signed. You can also look at the drain line or use compressed air to blow out blockages or trash.

2. Can You Spray Lysol In Your Car Vents?

If the air conditioner in your automobile has an unpleasant odor, it can be dirty. But instead of spending a lot of money to have your AC system cleaned, you can do it yourself with a can of Lysol disinfectant spray.

3. How Can I Tell If My Car’s AC Drain Line Is Clogged?

To prevent your car’s AC from smelling like poop, run it regularly to prevent mold and mildew buildup, use an AC cleaner to eliminate bacteria and fungus, and clean or replace the cabin air filter.

4. How Do I Get The Rotten Smell Out Of My Car Ac?

To remove the rotten smell from your car AC, you can try cleaning the evaporator coil and air ducts with a specialized cleaner, replacing the cabin air filter, and using an odor eliminator or air freshener designed for automotive use.

5. Why Does My Car Ac Smell Like A Dirty Diaper?

A dirty diaper-like smell in your car AC could indicate the presence of mold or bacteria in the system, often caused by moisture buildup. Cleaning the evaporator coil, replacing the cabin air filter, and using an air purifier can help eliminate the odor.

6. Why Does My Car Air Conditioner Smell Like Something Dead?

If your car’s AC smells like something dead, it could be from a decomposing animal trapped in the air ducts. To remove the smell, thoroughly clean the system with detergent and hot water, and replace the cabin air filter.

7. How Do I Get Rid Of Rat Smell In My Car Ac?

To remove the rat smell from your car’s AC, disassemble and clean the affected areas with detergent powder and crystal salt. Flush with hot water and repeat if needed until the odor is gone.

8. What Does Freon Leak In Car Smell Like?

A Freon leak in your car’s AC may produce a faint chloroform-like or sweet odor similar to car coolant. If you suspect a Freon leak, it’s essential to have the system inspected and repaired by a professional to prevent further issues.

9. Why Does My Ac Drain Line Smell Bad?

To combat the musty smell in your car’s AC during the summer months, try using a dehumidifier, running the fan mode after AC use, and consider adding air purifiers or natural odor absorbers to keep your car smelling fresh.

10. How Do I Get My Ac To Stop Smelling?

To prevent your AC from smelling, ensure proper drainage of condensate, clean the evaporator coil and air ducts regularly, replace the cabin air filter, and use air purifiers or odor absorbers to maintain fresh air quality.


Ultimately, an air conditioner that smells like poop can be stressful and unpleasant, making driving less fun. Many things could cause this smell, such as clogged drain lines, sewage leaks, mold and mildew, air vents, and stale air. Though it’s essential to do so, there are several things you may do to get rid of the smell and keep it from returning.


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