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Why does my car smell like rotten eggs?

    Why does my car smell like rotten eggs

    If your car smells like rotten eggs, you will probably first check the inside of the car to see if there are any food leftovers or animal waste by chance. But, in most cases, if the car smells like rotten eggs or smells of sulfur, then the reason is mechanical problems in the car. Even the mechanical problem can be of many types, which results in a rotten egg smell. So, what are the different reasons, and why does my car smell like rotten eggs?

    There are three main reasons why your car smells like rotten eggs. It includes a failing catalytic converter, malfunctioned fuel pressure motor, old transmission fluid, or even leaking battery acid. Apart from these, any other cause is unlikely to make your car smell like rotten eggs. However, you also need to check for if there are actual rotten eggs. 

    Let’s get to know about how these reasons can result in cars smelling like rotten eggs. 

    Reasons Why does my car smell like rotten eggs?

    Sulfur is the element most usually linked with the odor of rotten eggs. Sulfur is transformed into odorless sulfur dioxide throughout the emission process. The presence of sulfur implies that something went wrong throughout this process.

    The sulfur wasn’t properly converted during the combustion process. So, this can happen due to following reasons:

    1) Malfunctioned Catalytic Converter

    Your vehicle’s catalytic converter is meant to convert pollutants like hydrogen sulfide into innocuous, odorless gasses that do not contribute to air pollution. A malfunctioning or clogged catalytic converter cannot process sulfur gasses effectively. 

    This will prevent the catalytic converter from properly processing the gasses, resulting in a rotten egg odor or smell of sulfur. 

    2) Failing Fuel Pressure Sensor

    The fuel pressure sensor controls your vehicle’s fuel consumption. The car’s system will change fuel amount and timing as it passes through the system and into the engine based on the sensor readings.

    Having a bad fuel filter or a bad fuel pressure sensor may cause the catalytic converter to flood with oil, preventing it from performing at its best. Sulfur is deposited in the catalytic converter when the fuel filter is worn down, causing it to decompose. This result gives the rotten eggs smell. 

    3) Old Transmission Fluid

    The transmission fluid in your vehicle is meant to lubricate the rotating gears inside the transmission system. As with any other fluid in your car, the transmission fluid must be replaced as part of routine maintenance. 

    However, when the transmission fluid is old, it will leak into other systems, resulting in a rotten egg odor.

    4) Battery Acid Leak

    This can also be the possible reason for that rotten egg smell from your car. The smell of rotten eggs emanating from your car’s battery can be an indicator that battery acid is leaking from the unit. Additionally, you may observe corroded terminal caps or bubbling liquid seeping from a vent cap. 

    If the battery acid leaks, the battery cell could rupture, or the battery could even explode. So check for yourself if this is the reason or not. 

    Why does my car smell like rotten eggs when I turn on the ac?

    It is most probably due to the battery acid leaking in the car. Yes, there are other reasons why cars smell like rotten eggs, but if you are experiencing it after turning on the AC, then it is due to battery acid leakage. 

    Battery acid has a foul smell, and when it gets poured on the heated elements in the engine, it smells like rotten eggs. 

    However, if this is not the reason, then check for any other reasons like a catalytic converter or failing fuel pressure sensor. 

    Why does my car smell like rotten eggs when I start it?

    If you are experiencing rotten eggs smell from the car, the time you start it, then it is most likely happening due to the following four reasons:

    • Malfunctioned Catalytic Converter
    • Failing Fuel Pressure Sensor
    • Old Transmission Fluid
    • Battery Acid Leak

    Your car probably has one of these issues if it smells like rotten eggs. So check at a good mechanic and get the issue resolved as soon as possible. 

    Is a rotten egg smell in car dangerous?

    Yes, the odor of rotting eggs in your car might be hazardous. As previously stated, the odor is caused by inhaled hydrogen sulfide or sulfur. This gas can have negative consequences on your body; therefore, you should avoid it at all costs.

    Drive your vehicle immediately to your recommended mechanic. The odor will not be eliminated unless the underlying cause is addressed.

    Bottom Line

    So now you know why does my car smell like eggs. Check for the root cause as soon as possible and get it repaired by the mechanic. Also, drive with your windows open until repair as this gas can be dangerous for your body. 

    We hope this article was helpful & informative. Please leave your valuable thoughts & suggestions in the comments below!

    Thank you for reading!

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