Are you noticing some weird smell in your car, something like a rotten egg? You probably have asked yourself why does my car smell like rotten eggs? If that is the case, you shouldn’t worry because we are going to dissect everything in detail and share the ways you can fix this problem permanently.
Troubleshooting is key when it comes to these situations where you have problems like this. For starters, learning which components could fail and start to produce this smell is an excellent way to start your mechanical endeavors. Also knowing this will help you save some money in the long run. But why I’m saying this?
I’m saying this because out there are a lot of incompetent mechanics that will often misdiagnose your problems. So, you need to be a step ahead of them and don’t let them misdiagnose issues on your car. Doing this will save you thousands of dollars on possible repairs.
Some of them are just greedy and will ask you to replace a ton of parts and waste money before they find the real reason behind this. That’s why you shouldn’t be a naive person and learn more about what could go wrong.
That’s why in this article we are going to learn everything when it comes to rotten egg smell. We will learn what is this smell and should you be worried. Then we will cover why does my car smell like rotten eggs and we will discuss the reasons behind this smell. Later we will see how you can fix this and the costs to do so. So, let’s begin.
What Is A Rotten Egg Smell In Your Car?
If you never smelled a rotten egg, you probably are not familiar with this disgusting smell that will make you sick in a couple of seconds. Rotten eggs smell disgusting and for a reason. They start to decompose and the bacteria that are inside start to develop this smell.
More precisely the hydrogen sulfide, also known as sulfur. There is a slight amount of this chemical in the eggs and causes this smell to appear when the egg goes bad. And it’s one of the prime suspects of a lot of gut issues for a lot of people out there.
But what is also neat is that this hydrogen sulfide is found in a lot of other states. You will find this smell in sewer water, swamps, and other nasty places that you could imagine. But why is this the case? This is the case because there is a decomposition process, and the byproduct is the gas that is created when things start to decompose.
But, sulfur can also find its way into the automotive world. More precisely in car batteries and also in gas. So, you can expect this smell to appear from some of these components as well. When asked why does my car smell like rotten eggs? This might be the answer for you.
But you shouldn’t worry because we are going to further dissect this problem into smaller chunks and see if you should be worried and also the possible reasons behind this problem. When knowing the reasons why does my car smell like rotten eggs will help you solve the problem much quicker than you expected.
Should You Be Worried About The Rotten Egg Smell?
This is a good question and it deserves an elaborate answer. The answer is that, yes, you should be worried and take some action into solving this problem. Because anything that is not normal can indicate an issue that could potentially harm your vehicle’s performance and also harm your health.
Imagine breathing this rotten egg smell on a daily basis. This could affect your health greatly. That’s why driving with a rotten egg smell isn’t recommended for you as a driver and also it is not recommended for your occupants.
If you are a cab driver or an Uber driver let’s say, no passenger will want to ride with you because if you work in a small place. They will instantly know that your car has issues and will walk off after a mile or so.
Or if you take your friends on a Saturday night out, they will have a lot of comments for sure on what is causing this funky smell in your car and will possibly even mock you. That’s why if you notice a rotten egg smell in your car, you should be worried and take some steps into solving this problem.
Not to forget the mechanical problems that could come up if you don’t fix this problem sooner. The more you delay the solution for the problem. The more the problem gets bigger and bigger. And could cost you even thousands of dollars to fix. Later on, we are going to explain to you why this would be the case.
But first, you need to learn the reasons why does my car smell like rotten eggs and that we are going to cover in the following chapters.
Reasons Why Does My Car Smell Like Rotten Eggs?
Now we came to the important bit. And that is the possible reason behind this problem. Everything happens for a reason and you need to learn what are the possibilities when it comes to this problem. So, if you are interested, buckle up because we have a lot to cover.
1. Battery Leakage
The first reason why this problem happens is because of battery leakage. Every car has a battery that helps you start the car in the morning. Without it, you will not be able to start the car or use accessories like the dome lights, radio, infotainment, and other systems that are necessary for your vehicle to work properly.
Batteries are composed out of lead and acid. More precisely, sulfuric acid. This acid provokes a chemical reaction with the lead and produces electricity. We will not go into detail about this process since this isn’t the topic for today.
But the important thing is that these batteries are full of sulfuric acid. They can leak, either from the terminals or from the plastic housing if the housing has a defect. This will result in a rotten egg smell because of the sulfuric acid that is inside of the battery.
You can easily tell if the smell comes from your battery. Open up the hood and see the condition of the terminals. If there is rust buildup, it is obvious that there is a problem and this means that the acid goes out of the battery. Resulting in a rotten egg smell. So, when you are asking yourself why does my car smell like rotten eggs. It is quite useful first to check out the battery and see if it corroded and has leaks.
This problem can be patched in a few ways. But the best way to solve this issue is to replace the battery with a new one. A new battery will cost you around $100. Make sure that you get a quality battery that will last for a couple of years.
2. Transmission Fluid Leaks
Transmission fluid is also known to leak from the transmission pan. This is often caused by a bad transmission pan gasket that allows the transmission fluid to sip out bit by bit and when this fluid comes in contact with the hot components it tends to burn.
This burning fluid smell can also resemble a rotten egg smell and cause you to ask yourself why does my car smell like rotten eggs.
It is unfortunate that you cannot check this from the top of the car and you will need to find a place that you can access the car from underneath. In this situation, you will need a lift or jack stand on which you will be able to jack up the car in the air and inspect it.
If there is fluid around the oil pan. This is a clear sign that there is something wrong with it. The solution for this problem would be draining the transmission fluid and then replacing the fluid as well as the gasket material that is located on the transmission oil pan.
This will hopefully solve your problem and you will not experience this smell again. If you do this by yourself it’s going to cost you less than $100. But if you do this at a shop, it is highly likely that you will have to pay between $250 to $500. Depending on where you take your car for repair.
3. Fuel With Too Much Sulfur
Bad fuel can also cause this rotten egg smell. Every fuel has a certain amount of sulfur inside and if this sulfur has too much consistency. The catalytic converter will not be able to burn off this harmful gas.
So, the sulfur dioxide will escape from the catalytic converter that is located in your exhaust system. Causing rotten egg smell and making you ask yourself why does my car smell like rotten eggs. And you clearly don’t want that to happen to you.
If you notice a rotten egg smell coming inside of the cabin, you should crank open your windows and let this gas escape. This way, you will be sure that it will not harm your health.
The next thing to do is probably to change your gas station. Find another gas station and pour new fuel in. This fuel will mix with the old one and the smell will probably disappear. This can be one of the most basic reasons why you get a rotten egg smell. That’s why you should try it first and see if it works in solving your problem with this annoying smell.
4. Exhaust Leak
Exhaust leaks can also cause the engine to produce a rotten egg smell. As we know, there are a lot of emission devices from the engine to the rear of the car. Exhaust manifolds, O2 sensors, catalytic converters, and mufflers at the rear.
All these components have a crucial role in tackling emissions. So, if there is a leak in this system, there will be noises that will be heard as well as rotten egg smell. Instead of asking yourself why does my car smell like rotten eggs? It is useful to open up the hood and inspect the manifolds and also the manifold bolts.
Because there could be leaks in this system that will allow the gasses to escape before they reach the catalytic converter.
Having this problem will result in hissing noises as we mentioned above. In addition to this, a rotten egg smell could be present if you run a that is fuel-rich in sulfur. This could harm your health along the way.
Driving like this is not recommended and should be avoided at any cost. The best thing you can do is to drive with open windows to allow the air to circulate and clean off the cabin from the gasses. Then head up to the workshop and tell the mechanics to inspect the exhaust system.
Then they will do the repairs and replace the exhaust manifolds or the manifold bolts if some of them are broken. Even if you have holes in the exhaust they will patch them or replace the whole system. Or if you want to save some money, you can patch these holes on your own with clamps specific for exhaust leaks. Now let’s move on to the last possible cause.
5. Broken Catalytic Converter
The catalytic converter is crucial when it comes to destroying the harmful particles and if it doesn’t work properly. You will probably end up with problems. And one of the consequences will be the rotten egg smell that will be coming out from the exhaust. But why is this the case?
The catalytic converter has a special role in converting these harmful gasses and particles into something that isn’t so dangerous for us and the environment. And frankly, they are doing an excellent job when it comes to cleaning the pollution.
Without them, we were drowning in smog. If you take a look at pictures from New York or L.A from the ’60s or 50’s you would understand what I mean. The emission regulations from the ’70s made our lives better.
Nevertheless, these catalytic converters have a honeycomb structure on the inside (to find out more, check out our guide on what is a catalytic converter and what does it do). And they are made out of precious metals such as platinum, rhodium (to learn more, check out our guide on which catalytic converters have the most rhodium), and other metals. Making them quite expensive to purchase. That’s why they are the target of thefts. People just steal them and sell them for money in the junkyards.
That’s why you should pay attention to where you park your car overnight and stay away from some neighborhoods.
Also, when the catalytic converter as we mentioned when it gets clogged up or starts to disintegrate it will start to develop that rotten egg smell and will make you ask why does my car smell like rotten eggs? And the answer is simple, you either have to clean the catalytic converter or you will have to replace it if it is too far gone.
And in the following chapters, we are going to explain how you can fix it DIY.
How To Fix It DIY? – Why Does My Car Smell Like Rotten Eggs
Depending on how damaged is your catalytic converter will depend on how much it is going to cost you to fix it. Fixing it DIY will probably going to save you thousands of dollars and you will also learn something new along the way. Especially if you are not mechanically inclined this will be a good way to start your mechanical endeavors.
In the following chapters, we are going to explain how you can clean a clogged catalytic converter. So let’s begin.
1. Cleaning A Clogged Catalytic Converter By Running It On The Highway
Catalytic converters often clog up because people are driving the car a lot and are not aware that the catalytic converter has to be run at specific temperatures in order for it to work.
Running the car at short distances and in bumper-to-bumper traffic all the time will guarantee that the catalytic converter will get clogged up.
So, to avoid this happening to you, you will need to make sure that you drive your car every once in a while on the highway at higher RPM for a couple of minutes. This will make the catalytic converter heat up immensely and burn all of the debris that is located inside of the honeycomb (to learn more, check out our guide on how does a catalytic converter work and what is a catalytic converter as well as what does a catalytic converter look like) and is preventing the gas to escape and cause that rotten egg smell.
Sometimes a good thrashing is all your car needs to fix these problems. In addition to this, there are solutions like Cata Clean. This solution is poured into the gas tank and then you take your car for a ride on the highway. The high temperatures and this solution will make all the debris burn off and dissolve completely. So, you will have a properly working catalytic converter once again.
But sometimes, if the catalytic converter is too clogged. You will need to remove it and manually clean it. And how you can perform this work we are going to explain in the following chapter.
2. Manually Cleaning It If Your Car Still Smells Like Rotten Eggs
We have answered the question of why does my car smell like rotten eggs. Now let’s see how you can clean the catalytic converter manually.
There are a lot of companies that are cleaning diesel particulate filters and they could also clean a simple car catalytic converter as well. Since both of these components are pretty much the same. You will pay some penny for this service. But your catalytic converter will be good as new once they finish cleaning it.
Or you can even try and clean it by yourself. A lot of people claim that the lacquer cleaner method really works. You just place the catalytic converter into this solution and then clean it off with a high-pressure water hose. A good method to try, but it doesn’t always work, especially if the catalytic converter is too clogged up. The only solution for this problem is to replace it with a used one or a new one.
3. Replacing The Catalytic Converter
Replacing the catalytic converter should be your last resort. When replacing the catalytic converter, you should consider getting a used one. Because you can find a used catalytic converter for good money (you can learn more in our write-up on who buys used catalytic converters near me). Not crazy expensive as getting a brand new one.
If you have an older car, go to your local junkyard and try to harvest one from an old vehicle. It might be not in the best condition. But it will get the job done properly. Or go on the marketplace and look for people that sell used catalytic converters and you might get lucky and get a good deal. But either way, you can expect to pay a good penny for it.
Cost To Replace The Catalytic Converter
The cost to replace the catalytic converter can vary depending on what make and model you are running. Since not all makes are that affordable to own. Either way, the catalytic converters are quite expensive to buy.
Even a used catalytic converter is going to cost you at least $1,000 to purchase. New ones go from $1,500 and up to a few grand. Which is insane. But that is the price to pay when it comes to fixing this problem. It is not a favorite problem for a lot of people to solve. But it is what it is. In the end, you will not ask the question of why does my car smell like rotten eggs. Which will be a good thing.
Car Smells and Their Possible Causes: 6 Need-to-Know Facts
- A gas smell in your car may indicate gasoline on your clothing (you can learn more in our guide on how to get gasoline out of clothes), but if it lasts longer than a few hours, it could mean issues with your gas cap, fuel tank, or injector.
- Exhaust fumes inside your car indicate a leak in your car’s exhaust system or poor seals on windows and doors, which can be dangerous and should be taken to a technician immediately.
- A rotten egg smell could mean a malfunctioning part in the fuel system, such as a worn-out catalytic converter or fuel filter, which can be dangerous if left unaddressed.
- Burning rubber smells can be caused by a loose rubber hose or belt, an oil or fluid leak, or worn-out drive belts that need expert engine repair.
- Burning smells that don’t smell like rubber could mean several things, including burned-out electrical fuses, an overheating A/C compressor, or worn-out brake pads.
- Musty smells from the A/C vents may indicate mold or mildew in the system caused by excess moisture buildup (it helps if you figure out how to get mildew smell out of car), which can be hazardous to your health and should be taken care of by a trained technician.
Conclusion – Why Does My Car Smell Like Rotten Eggs
In this article, we covered a lot when it comes to the rotten egg smell. We learned what this smell is and why does it appear. We learned all the possible reasons why does my car smell like rotten eggs.
And there were quite a few of them. Most notably, the bad car battery, exhaust leaks, and also the bad catalytic converter which is the most logical reason.
That’s why we devoted a few chapters on this reason and we elaborated in-depth on the ways that you can fix or replace a catalytic converter with a new one and on what cost would that be. As we noted, catalytic converters are not cheap and cost a good penny to purchase even used. Because they are made out of precious metals that cost a lot of money to get.