Why Does My Car Smell Like Ammonia – Latest Findings 2023

Have you ever noticed a peculiar smell resembling ammonia in your car’s interior or emanating from the exhaust? If so, you’re not alone. Many vehicle owners have encountered this perplexing issue and are eager to uncover its origins. 

The smell of ammonia in cars can be attributed to various factors, such as black mold growth on the AC evaporator coil or a rich running engine causing the catalytic converter to emit strong odors. 

These components, integral to your vehicle’s performance, are responsible for reducing harmful emissions. Understanding the implications of an ammonia-like smell is crucial for both your car’s well-being and your own safety. 

In this article, we will delve into the potential causes of this issue and provide you with valuable insights and solutions, ensuring a pleasant driving experience and peace of mind for our readers.

Do Not Forget to Read About: Best and Latest Air Purifiers

Why Does My Car Smell Like Ammonia

Why Does My Car Smell Like Ammonia

One crucial component that often goes unnoticed but plays a vital role in ensuring our safety and the environment’s well-being is the car exhaust system. 

Now, I will delve into the definition and function of car exhaust, the components of the exhaust system, the role of the catalytic converter, and the reasons why car exhaust sometimes emits a pungent ammonia-like smell.

Understanding Car Exhaust

The car exhaust system serves as the mechanism that removes poisonous gases generated by the engine during the combustion process. 

It is responsible for expelling these harmful gases, such as carbon monoxide, nitrogen dioxide, hydrocarbons, and other pollutants, through the tailpipe, thus preventing their escape into the atmosphere.

Components of the Exhaust System

Engine: The exhaust system begins with the engine itself. During operation, the engine generates heat and pressure, leading to the formation of gases.

Exhaust Manifold: The gases produced by the engine are directed into the exhaust manifold, a component designed to collect and channel them.

Catalytic Converter: The gases from the manifold then pass through the catalytic converter. This crucial component plays a significant role in reducing the harmful pollutants emitted by the engine. It employs a chemical reaction to burn off pollutants and convert them into less harmful substances before they exit the exhaust system.

Muffler: After passing through the catalytic converter, the remaining gases travel through the muffler. The muffler’s primary function is to slow down and cool the gases, reducing noise levels and providing further emission control.

Tailpipe: Finally, the gases exit the exhaust system through the tailpipe, releasing them away from the vehicle’s occupants and the environment.

Role of the Catalytic Converter

The catalytic converter stands as a crucial component in the exhaust system, playing a pivotal role in reducing harmful emissions. 

It employs a catalyst, typically consisting of platinum, palladium, and rhodium, to facilitate chemical reactions that transform toxic gases into less harmful substances. 

Through a process called oxidation, the catalytic converter converts carbon monoxide into carbon dioxide and converts nitrogen dioxide into nitrogen and oxygen. 

It also assists in reducing hydrocarbon emissions. This chemical wizardry helps protect the environment and contributes to cleaner air quality.

Reasons Why Car Exhaust Smells Like Ammonia

Occasionally, you may encounter a rather unpleasant odor emanating from your car’s exhaust, resembling that of ammonia. Several factors can contribute to this phenomenon:

Clogged Fuel Injection System: A clogged or malfunctioning fuel injection system can lead to incomplete combustion, resulting in unburned fuel escaping through the exhaust. This unburned fuel may contain traces of ammonia, causing the exhaust to emit an ammonia-like smell.

Leak in the Fuel System: A leak in the fuel system, such as a hole in the exhaust manifold, can allow gases to escape before undergoing proper combustion. These gases may contain hydrogen sulfide, which, when released, produces a rotten egg-like odor resembling ammonia.

Faulty Catalytic Converter: A malfunctioning or damaged catalytic converter may fail to convert pollutants effectively, leading to the release of various compounds, including ammonia, sulfur dioxide, or other pollutants. This can result in the exhaust emitting an ammonia-like smell.

9 Common Reasons Why Does My Car Smell Like Ammonia

Now, we will explore these reasons and discuss potential solutions to address the issue effectively.

Exhaust System Leak:

One of the primary causes of an ammonia smell in a car’s exhaust is a leak in the exhaust system. When there are holes or cracks in the manifold or other exhaust components, gases escape, resulting in the distinctive smell. The leaked gas contains hydrogen sulfide, which is responsible for the ammonia-like odor.

Hydrogen Sulfide: The Culprit:

Hydrogen sulfide, a poisonous gas commonly found in natural gas and known for its rotten egg smell, is a component of the leaked gas. 

When hydrogen sulfide mixes with the exhaust gases, it gives rise to the ammonia-like smell that can be detected from the car’s exhaust.

Potential Dangers:

Breathing in hydrogen sulfide can be hazardous to health. Therefore, it is crucial to take immediate action if you smell this noxious odor. If you notice an ammonia-like smell in your car’s exhaust, it is advised to exit the vehicle and seek assistance from a professional mechanic.

Faulty Catalytic Converter:

Another possible reason for the ammonia smell in the exhaust is a faulty catalytic converter. The catalytic converter plays a vital role in converting harmful gases into harmless substances. 

However, when it malfunctions, the conversion process is compromised, leading to the release of pollutants such as ammonia and sulfur dioxide, which contribute to the unpleasant odor.

Resolving Catalytic Converter Issues:

To address a faulty catalytic converter, it may be necessary to replace it entirely. Alternatively, using a catalytic converter cleaner can help eliminate deposits and improve its performance, effectively reducing the ammonia smell from the exhaust.

Fuel Injection System Problems:

Issues with the fuel injection system can also be responsible for the ammonia smell in the exhaust. This can occur due to a faulty fuel injector or an air leak within the system. 

If you suspect problems with the fuel injection system, it is advisable to have your car undergo a diagnostic test to identify and resolve the underlying issues.

Dirty or Clogged Fuel Injectors:

Dirty or clogged fuel injectors can disrupt the proper mixing of fuel with the necessary air for combustion. This imbalance in the fuel-to-air mixture can result in an increased presence of ammonia molecules in the exhaust. 

Regular cleaning and maintenance of the fuel injection system can help prevent such issues and minimize the ammonia smell.

Coolant Leakage:

Ammonia smell from the exhaust can also be attributed to coolant leakage within the vehicle. When coolant leaks and mixes with the exhaust gases, it can emit an ammonia-like odor. 

Identifying and repairing coolant leaks promptly is essential to eliminate this particular cause of the smell.

Paint Thinner Residue:

In some cases, an ammonia odor may be present in the exhaust due to the presence of hydrocarbons from paint thinner. If the car has recently been painted, residual paint thinner can release hydrocarbons into the exhaust, resulting in the ammonia smell. 

Unfortunately, there is no immediate solution to remove the smell, and it may gradually fade over time. Using an air freshener can help mask the odor temporarily.

How to Get Rid of Ammonia Like Smell From Your Car

From inspecting the catalytic converter to using environmentally friendly fuels and practicing regular maintenance, we will explore effective ways to eliminate the unpleasant odor and ensure a safe and odor-free driving experience.

Inspect and Replace the Catalytic Converter:

If your car exhaust emits an ammonia smell, start by inspecting the catalytic converter. Consider replacing it if necessary, as a faulty converter can lead to the presence of odorous gases.

Clean the Emission System:

Clogs in the emission system can contribute to the ammonia smell. Cleaning the system or seeking professional repairs can address these clogs and improve the overall performance of the vehicle.

Consider Environmentally Friendly Fuels:

Reducing the emission of pollutants can be achieved by using biodiesel or other eco-friendly fuel options. Making this switch can help minimize the ammonia-like odor in your car’s exhaust.

Utilize Vehicle-Specific Air Fresheners:

After cleaning your car, use air fresheners specifically designed for vehicles. These air fresheners effectively mask odors, especially when applied to upholstery, mats, and carpets.

Allow for Proper Ventilation:

Drive with all windows open for at least 30 minutes to allow the car to circulate air. This practice helps disperse contaminants and trapped odors, ensuring a fresher interior environment.

Apply Aerosol Fragrances:

To cover the smell of paint thinner or other strong odors, use aerosol fragrances such as pine or apple. These scents provide a pleasant aroma and effectively mask unwanted smells.

Seal Leaks and Improve Airflow:

Identify and seal any leaks in the vehicle using duct tape or caulk. Additionally, cover floorboard holes with plywood if necessary. Enhance airflow by installing vents or using air filters to promote better air circulation within the car.

Prioritize Regular Maintenance:

If the ammonia smell persists, it is advisable to consult a professional repair shop. They can identify and address any faulty components that may be causing the odor. Regular inspection and maintenance of the vehicle are crucial for both safety and longevity.

Remove Paint Thinner Smell:

To eliminate the smell of paint thinner from your car, use aerosol scents such as pine or apple, which effectively cover up the odor. Vacuum the car and apply air fresheners, being cautious not to spray near vents.

Deep Clean Upholstery and Carpets:

Use a mixture of water and detergent in a spray bottle to remove stains and odors from upholstery and carpets. For stubborn stains or stronger odors, wash affected areas with soap before spraying the mixture.

Neutralize Odors on Skin and Clothes:

If exposed to emissions resulting in a paint thinner smell on your skin or clothes, wash them with baking soda for approximately 30 minutes. Alternatively, apply a small amount of baby oil to remove the paint thinner odor from your hands.

Further Information: Best Air Purifier for Car

Final Words

The presence of an ammonia-like smell in your car can be concerning and may indicate underlying issues that require attention. 

Understanding the causes of this odor, such as a clogged fuel injection system, a leak in the fuel system, or a faulty catalytic converter, is crucial for addressing the problem effectively. 

Taking immediate action and seeking professional assistance is essential to ensure your safety and the well-being of your vehicle. 

By inspecting and replacing the catalytic converter, cleaning the emission system, using environmentally friendly fuels, and practicing regular maintenance, you can eliminate the unpleasant odor and enjoy a safe and odor-free driving experience.

Remember to prioritize proper ventilation, utilize vehicle-specific air fresheners, and address any leaks or airflow issues to maintain a fresh interior environment. 

By following these steps, you can resolve the ammonia-like smell in your car and ensure a pleasant driving experience and peace of mind.

Frequently Asked Questions

How can I get the smell of paint thinner out of my car?

To get rid of the smell of paint thinner in your car, you can try the following steps:

Open all the windows and doors of your car to allow fresh air to circulate.

Vacuum the interior of your car to remove any residual paint or thinner particles.

Clean the affected surfaces using a mixture of warm water and mild detergent or an upholstery cleaner.

Place bowls of activated charcoal, coffee grounds, or baking soda in your car overnight to absorb the odor.

Use an odor-neutralizing spray specifically designed for automotive interiors.

If the smell persists, you may consider using an ozone generator or seeking professional cleaning services.

How can I tell if my car is polluting?

There are a few signs that can indicate if your car is polluting excessively:

Dark or thick smoke coming from the exhaust pipe, especially if it has a strong, unpleasant odor.

Soot or black residue on the rear bumper or around the exhaust pipe.

Unusual or strong smells coming from the exhaust, such as a sulfuric or rotten egg smell.

Decreased fuel efficiency, requiring more frequent refueling than usual.

Increased emissions-related warning lights on the dashboard, such as the “Check Engine” light.

Why does my car exhaust smell so strong?

A strong smell from your car exhaust could indicate several potential issues, including:

Rich fuel mixture: If the fuel-to-air ratio is too high, it can result in incomplete combustion and produce a strong smell. This could be caused by a faulty oxygen sensor, a clogged air filter, or a malfunctioning fuel injector.

Burning oil: If your car is burning oil, it can create a distinct odor. This might be due to a leaking gasket, worn piston rings, or other engine problems.

Catalytic converter issues: A failing catalytic converter may lead to a sulfuric or rotten egg smell.

What are the signs of a blown head gasket?

The following signs may indicate a blown head gasket in your car:

Overheating engine: If your engine frequently overheats or experiences sudden temperature spikes, it could be a sign of a blown head gasket.

White or milky substance in the oil or coolant: A blown head gasket can cause coolant and oil to mix, resulting in a creamy or milky appearance.

Continuous coolant loss: If you notice a constant need to refill the coolant without any apparent leaks, it could be due to a blown head gasket.

White smoke from the exhaust pipe: A blown head gasket can cause coolant to enter the combustion chamber, resulting in white smoke coming from the exhaust.

Engine misfires or poor performance: A blown head gasket can lead to compression loss, causing the engine to misfire, run poorly, or experience a loss of power.

How does burning transmission fluid smell?

Burning transmission fluid can produce a distinct and unpleasant odor. It is often described as a burnt or acrid smell, similar to that of overheated or burning oil. The smell may become more noticeable when the transmission is under heavy load or during prolonged driving. If you detect a strong burning smell resembling transmission fluid, it could indicate an issue with your transmission, such as overheating, low fluid levels, or worn-out components. It is advisable to have your vehicle inspected by a qualified mechanic to diagnose and address any potential problems with the transmission.

How can I stop exhaust fumes from entering my car?

To prevent exhaust fumes from entering your car’s interior, consider the following measures:

Ensure the windows and sunroof are properly closed while driving.

Check the weather-stripping around the doors and windows for any signs of wear or damage. Replace or repair as necessary to maintain a proper seal.

Regularly inspect the exhaust system for leaks, including the exhaust manifold, gaskets, and joints. Have any leaks repaired promptly by a professional.

Avoid idling your car in enclosed spaces, such as garages, for prolonged periods.

Keep the ventilation system in your car well-maintained and ensure the cabin air filters are clean and functional.

Kristen Park - Specialised Content Writer for Caresh Fresh


My name is Kristen Park and I am a senior writer specialising in how-to guides and home cleaning information at Cares Fresh. As a researcher, I take pride in digging deep to find every small detail on a topic and explaining it in a way that is easy for the reader to understand.