Are you tired of the car smells like rotten eggs when getting into it? If yes, then you are not alone, as there are many car drivers who are going through the same issue. A sulphurous odor in your car can be caused by a variety of factors, and it’s not always easy to determine the source. Also, servicing the car or washing it properly could let you find its reasons to some extent, but there are other factors too that you are unaware of.
But don’t worry, this article delves into the reasons why your car is smelling like rotten eggs and how you can fix it so that you can drive odor-free.
Most Common Reasons of Why Car Smells Like Rotten Eggs
A fresh smell and a peaceful environment in the car are very necessary to drive efficiently and effectively. However, when a car smells like rotten eggs while starting, it can affect driving capability, so knowing the reasons mentioned below is necessary for driving properly.
1. Catalytic Converter Issues
The catalytic converter is a very crucial element of your car’s exhaust system. This is responsible for converting harmful pollutants in the exhaust gases into harmless carbon dioxide and water vapor. But if the catalytic converter becomes clogged or damaged, it can cause a buildup of sulphur dioxide in the exhaust system, further creating a rotten egg smell in car.
2. Faulty Fuel Pressure Sensor
Fuel injectors are generally responsible for spraying fuel into the engine’s cylinders, where it’s mixed with air and ignited to produce power. However, a faulty fuel pressure sensor due to dirt or clogging causes engines to run rich and thus leads to the buildup of unburned fuel in the exhaust system. This can cause a car smell like eggs, especially if the fuel contains high levels of sulphur.
3. Old Transmission Fluid
When your car smells like rotten eggs and won’t start, old transmission fluid might be another reason because of the breakdown of the fluid’s additives and the formation of sulphur compounds. This happens as transmission fluid ages; it can become contaminated with debris and particles that can cause the fluid to degrade and break down, causing a foul smell when you enter the car.
4. Forgotten Food or Groceries
The forgotten food or groceries remaining within the car seat, covers, or nearby clutch areas might cause the car smells like rotten eggs when starting. This happens because the rotten food items create sulphur gas, and thus it smells badly if not uncleared.
5. Dead Animals
The dead animals, like rats, lizards, or others, are another cause for a rotten egg-like smell within the car. These are nesting in your car’s engine compartment or trunk, and they can leave behind droppings and urine that contain high levels of sulphur.
6. Battery & Electrical Issues
If your car’s battery is old or failing, it can cause a buildup of hydrogen sulfide gas, which has a strong, sulphurous odor. This is especially common in cars with older batteries or those that are not properly maintained. Also, electrical issues, such as a faulty alternator or a short circuit, can cause a buildup of sulphur dioxide in the exhaust system, leading to a rotten egg smell.
Also Read: Why Does My Car Air Conditioning Smell?
Things To Do When Your Car Smells Like Rotten Eggs

As you discover the most common causes of rotten egg smell in the car, let’s talk about how you can remove it effectively.
1. Check the Fuel
If you suspect that the fuel is the source of the odor, try switching to a different brand or type of fuel. You can also try adding a fuel additive to help reduce the sulphur content, or get car service Perth by experts if unable to detect the fuel capacity on your own.
2. Inspect the Catalytic Converter
If you suspect that the catalytic converter is the source of the odor, have it inspected by an auto mechanic, and if it’s clogged or damaged, it may need to be replaced with a new one.
3. Clean the Fuel Inspectors
If you suspect that the fuel injectors are the source of the odor, try cleaning them with a fuel injector cleaner. You can also try replacing the fuel filter to ensure that the fuel injectors are getting clean fuel. Alternatively, look for a car workshop near me to ease the process.
4. Check the Battery
If you suspect that the battery is the source of the odor, have it inspected by a mechanic near me. If it’s old or failing, it may need to be replaced.
5. See the electrical issue
If you suspect that an electrical issue is the source of the odor, have it inspected by a mobile car care service provider. If there’s a short circuit or other electrical issue, it will need to be repaired to prevent further damage.
6. Check the Cooling System
If you suspect that the cooling system is the source of the odor, have it inspected by a mechanic. If there’s a leak, it will need to be repaired to prevent further damage.
7. Check for rodents
If you suspect that rodents are the source of the odor, try setting traps or using repellents to get rid of them. You should either do deep cleaning by washing your car properly both internally as well as externally, or call on a car cleaning services provider to do the same.
Looking For A Reliable Mobile Auto Mechanic?

Everyone wants to drive a fresh-smelling car. However, if it smells like rotten eggs, the above can be major reasons. But as every problem has a solution, these smells can be wiped off if you reach a professional car cleaning Perth.
At SAI Auto Care, you get the best car wash in Perth, and ensure that you take back home a refreshed car. We have skilled mechanics who work professionally to wash, repair, and refit to look like new.
FAQs
1. How can I fix the rotten egg smell in my car?
Answer 1:
You can easily fix the rotten egg smell in your car by checking for fuel, battery, electrical issues, rodents, or any dead animals. However, if unable to unlock the secrets, the professionals will help you to make your four-wheeler smell refreshed again.
2. Is a car AC causing the rotten egg smell?
Answer 2:
Yes, an air conditioner (AC) fixed in a car may cause a rotten egg smell because the growth of mold and bacteria in the AC system produces a strong, sulphurous odor. Also, if the AC system is not properly maintained, it can cause the refrigerant to leak, leading to the formation of sulphur compounds that can also contribute to the rotten egg smell.
3. Can a bad alternator smell like rotten eggs?
Answer 3:
Of course, a bad alternator can smell like rotten eggs. A failing alternator can cause the battery to overcharge, leading to the production of hydrogen sulfide gas, which has a strong, sulphurous odor similar to rotten eggs.
4. How do I fix stinky car air?
Answer 4:
If you want to fix stinky car air, you can follow the given steps-
1] Check and replace the air filter,
2] Vacuum the interior and trunk,
3] Use a deodorizing spray or essential oils,
4] Check for mold and mildew in the AC system, and
5] Have your car’s electrical system checked for any issues that may be causing the odor.
5. How to get rid of rotten smell in car fast?
Answer 5:
If you want to get rid of the rotten smell in your car fast, you must consult the best car wash in Perth, where a professional mechanic washes your car properly and deeply.