Rotten Egg Smell in Car? Here's What Might Be Causing It

Ben Guess
· 4 min read
Drivers depend on their senses to navigate and guide them when they drive. We watch the road, we listen to the familiar
sounds the car makes
— and we notice when we hear something different.
Smelling something unusual, like rotten eggs, should also set off our sense alarms. If you smell anything like sulfur or rotten eggs, here’s why it might be happening, what you should do, and the kind of
car repair
your vehicle may need.
If you smell rotten eggs in your car, this might indicate a mechanical problem with your vehicle.

Why does my car reek of rotten eggs?

The smell of rotten eggs in your car is a sign that there might be a problem with your catalytic converter or your transmission fluid, according to
McSpadden's Tire & Automotive
. Your vehicle is designed to convert the sulfur found in fuel to a neutral-smelling compound during combustion. It is then further neutralized in the car's emissions system. 
However, if the converter is damaged or clogged — for example, if a faulty fuel pressure sensor or filter floods your converter with oil — sulfur gas can leak out into your car's cabin area. The unpleasant odor is a sign that you need to have your car checked, as
Motor Biscuit
notes that continuing to drive with a broken catalytic converter can overheat your exhaust system.
Transmission fluid
can also be responsible for the smell. If your transmission fluid leaks and comes into contact with the hot engine, or if it simply needs changing, it may start to produce a rotten egg odor.
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What should I do if I notice a smell in my car

It's smart to make an appointment with a trusted mechanic right away if you smell rotten eggs in your car. This odor usually means something is functionally wrong with your vehicle, and
a mechanic or auto shop
will have the tools to properly diagnose and fix the problem.
qualified mechanic
will take a look and determine which part of your car is the cause of the offensive smell. The catalytic converter might have to be replaced or repaired. If your car is a newer purchase, the work and parts might be covered under your
original warranty
Catching problems with fuel pressure sensors or filters early on makes them easier and less costly to fix.
If this is your first time seeing a mechanic in awhile, it might be a good idea to set up a
maintenance schedule
. Regular maintenance checks with your favorite automotive shop can help catch issues like these before they start affecting you or your car, so it’s always a good idea to take in your vehicle on a regular basis.

What other smells might be signs of car trouble?

There are several other odors drivers might encounter on their
morning commute
. If a gasoline smell lingers long after you fill the tank, it could simply be that you got some on your shoes or clothes. But it could also mean there is a leak in the car's fuel injection line or vent hose. This is a potentially dangerous issue requiring professional diagnosis and repair, according to
Fred Beans
A burning rubber smell often indicates that a belt or rubber hose has come loose or started wearing out and is touching the hot engine. Other burning smells could signal a burned-out electrical fuse or that your brake pads are worn down and in need of replacement.
A sweet, syrupy odor could indicate a leak in your vehicle's radiator or heating system. The smell of ethylene in the coolant is usually most discernible when the car is running or just turned off. It's a good idea to have it checked as soon as possible, since this leak can cause major systems to break down.

Regular car maintenance starts with good car insurance

Keeping your car in tip-top shape requires regular visits to a qualified automotive mechanic, but unexpected repairs can also be unexpectedly pricey. If you want to save a little extra money to fix any car issues you may run into, a good place to start is by reviewing your car insurance policy and ensuring that you’re getting the best deal on your coverage.
One good way to do this easily is with
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