When you’ve had a car for a long time, it’s completely normal for problems to show up out of the blue. Things like a flat tire, an overheated engine, and worn-out brake pads are all annoying in their own ways, but nothing is more annoying than a strong smell.

Why is My Car Smelling Like Rotten Eggs?

Most of the time, sulfur is to blame for the smell of rotten eggs. If it comes from inside your car, it could be a big problem because fuel has sulfur in it, which is burned and then turned into a compound that doesn’t smell bad in your car’s emission system.

Even after you change the transmission oil if your car still smells like rotten eggs, here are some common things that could be wrong.

car smelling like rotten eggs

Waste build-up on the catalytic converter

A vehicle’s catalytic converter gets rid of emissions like hydrogen sulfide and smells that aren’t harmful. This keeps the air from getting dirty. If a lot of waste builds up on the catalytic converter, it will overheat and give off a rotten egg smell inside the car.

If it gets clogged, it won’t be able to neutralize sulfur gas, and dangerous, intense sulfur gas will leak out. The only way to fix this is to replace the whole thing.

Broken catalytic converter

The fuel pressure sensor controls the amount of fuel that goes into the engine. If the pressure sensor is broken, the catalytic converter will get too much oil. If the catalytic converter is broken, it will leak sulfuric gases, which will make your car smell like rotten eggs.

When you smell a smell in your car, the first thing you should do is check the fuel filters and sensors.

Transmission Fluid leak

Transmission fluid keeps the gears in a car running smoothly and should stay in the engine. If that’s no longer the case and there’s a leak, you might smell a strong smell. The problem should be fixed if you change the transmission fluid as often as the car’s maker suggests and clean up the puddles.

Other Typical Causes

There could be other smells coming from your car that could be scary. Sometimes the air conditioner vents smell like gas, and sometimes they smell musty. To figure out what’s wrong with the car and fix it, you need to know what smells it gives off.

It smells like gas.

If your car smells like gas, it could be because the gas cap, the fuel tank, or the injector is leaking. If the fuel tank leak isn’t found quickly, it can cause a lot of trouble.

The fumes from the car.

It’s dangerous that the car smells like exhaust fumes. If exhaust fumes get into the car, they can kill the people inside. If your car’s exhaust system is leaking, take it to a mechanic as soon as possible.

Smells like rubber.

If you don’t drive race cars, the smell of rubber in your car is a problem. Under the hood, the rubber hose or the belt sometimes comes off. If the rubber hose touches a hot part of the engine, it melts and gives off a foul smell.

The smell of water that is clogged.

If there is too much moisture in the car’s air filters or drain lines, it can smell musty.


If your car smells like rotten eggs, there might be a problem with the catalytic converter, the fuel pressure regulator, the fuel filter, or even the old transmission fluid. No matter what the cause is, if your car smells like rotten eggs, you should take it to a mechanic as soon as possible to fix the problem.

The mechanic will figure out which part is broken and fix or replace it before it gets worse and hurts other parts of the engine. If you don’t fix this problem, your car could stop working in the middle of the road.

Chris Miller

Chris Miller is an auto journalist who specializes in reviewing new cars and providing helpful advice on family vehicles. He has a passion for cars and enjoys sharing his knowledge and expertise with others.

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