Why Does My Car Smell Sulfur: 7 Common Reasons

You just woke up in the morning to start your vehicle just for you to smell a strong sulfur smell oozing out.

There’s no need to fret, it might be a problem with the catalytic converter, and it could be that your car is excellent.

The sulfur smell is mainly caused by the inability of the fuel to convert hydrogen sulfide present in power into sulfur dioxide. 

When there’s a problem with the exhaust system, the conversion won’t take place effectively, leading to a rotten egg smell.

Dive in to discover the causes of sulfuric smell in vehicles and how to tackle it.

1. Faulty Catalytic Converter

A catalytic converter is a component of a vehicle’s emission system.

It helps in filtering and reducing the harmful substances that the internal combustion engine release into the atmosphere.

Hydrogen sulfide is one of the most harmful substances released as a by-product of gas-fueled vehicles.

This gas has a rotten egg-like smell. However, the platinum present in the catalytic converter detoxifies it and turns it into sulfur dioxide, which is an odorless gas.

When your catalytic converter is broken or not functioning correctly, it won’t be able to convert this gas into sulfur dioxide.

This leads to your vehicle with an irksome sulfuric smell.

A faulty catalytic converter can also lead to problems starting your car engine and excess gas consumption.

If you sense that your catalytic converter is faulty, hurriedly contact your mechanic, as a defective converter can cause high temperatures to fire accidents.

2. An Old Transmission Fluid

The transmission fluid helps lubricate the moving parts of a car, thus reducing friction and keeping the transmission cool.

Most older cars use a manual transmission with sulfur-based lubricants, which produces a potent sulfuric smell when they drip out.

Not flushing your transmission fluid can lead to an old dirty, and stinking transmission fluid.

If it gets worse, the liquid might leak into the hot engine, spoiling gaskets and gears, which can be an expensive repair.

You don’t have to change your transmission fluid every time you visit your mechanic for an oil service.

It would help if you gave your vehicle a transmission fluid flush every 60,000 miles or as suggested by your car manufacturer.

3. Worn Out Fuel Filter

A fuel filter helps filter out dirt and dust from the vehicle engine to ensure it runs smoothly and effectively.

When the filter starts wearing out, fuel rich in sulfur will be released into the catalytic converter burning it out and causing your vehicle to smell sulfur.

While changing your fuel filter won’t cost much, changing a faulty catalytic converter can cost hundreds of dollars. 

Thus, you must replace a faulty fuel filter immediately.

4. Faulty Fuel Pressure Sensor

The function of a fuel pressure sensor is to monitor your vehicle’s fuel pressure and consumption rate.

Once your fuel pressure sensor fails, more fuel will be heading toward the engine, thus putting more pressure on the catalytic converter to filter out harmful substances.

If this becomes more than what the catalytic converter can handle, it can lead to an influx of sulfur which will cause the smell of rotten eggs.

Other signs of faulty fuel pressure sensor include:

• Excess fuel consumption.
• Difficulty accelerating.
• Difficulty in starting your vehicle.
• Check engine light turning on.

You must see your mechanic once you notice these signs on your vehicle.

That way, you’ll be able to save yourself from investing in fuel pressure sensors and catalytic converters.

5. Bad Car Battery

Well, it might not be the catalytic converter; or battery battering.

A car battery contains sulfuric acid that’s confined in the battery case. This acid only leaks out when the battery is faulty, leading to an irritating rotten egg smell.

If your battery case is cracked and battery acids start leaking out, quickly contact your mechanic to have it fixed.

Avoid jump-starting a lousy car battery, as it can lead to a fire explosion.

6. Damaged Exhaust System

A damaged exhaust engine can lead to an exhaust leak causing harmful unfiltered exhaust fumes to leak out.

Too much leakage can lead to an awful, disgusting sulfuric smell.

Also, a bad oxygen sensor can accumulate too much fuel in the combustion chamber. This will choke your catalytic converter leading to a sulfur smell.

Avoid delay in fixing a damaged exhaust system as it can expose you to the deadly carbon monoxide.

Once you notice your exhaust sounds are becoming louder, quickly open windows to prevent harmful gases from accumulating and call your mechanic immediately.

7. An Actual Rotten Egg

Since hydrogen sulfide smells like rotten eggs, the cause of that sulfuric-like smell in your vehicle might be an egg!

This is especially if you allow eating in your car.

If the cause of the foul smell is an actual rotten egg, thank goodness your vehicle isn’t in trouble.

However, you’d need to clean it up to restore its fresh atmosphere thoroughly.

What’s the Solution to the Sulfur Smell in My Car?

The best way to eliminate the sulfur smell in your vehicle is to fix or replace the faulty part that’s causing it.

This could be a fuel pressure sensor, a dying battery, or a catalytic converter. Old transmission fluid or a leaky exhaust system can also cause a sulfur smell.

Once the root of the problem has been fixed, you should be able to get rid of the smell. Ensure you fix these problems early before they extend to other car parts.

But what if the smell has already penetrated the interior of your vehicle? We’ve some tips for you!

• Open all windows or doors and allow fresh air to circulate for some minutes.
• Clean all crevices of car seats and carpets.
• Rub the baking powder on the carpets, allow them to rest for some minutes then clean them thoroughly.
• Drop a piece of grilling charcoal in your vehicle and watch it absorb the smell away.
• To give your vehicle a more pleasant smell, consider dropping a bag of grounded coffee, soaked cotton balls of vanilla or mint extract, or use a car freshener.
• Contact professional car cleaners to clean your vehicle thoroughly.

What If It’s Not a Sulfur Smell?

There are several other smells that your vehicle can emit. A lingering gasoline smell after refilling your tank might indicate a leaky fuel system.

If your car smells burning rubber, it might be an indication that there’s a loose rubber that’s touching the hot engine. It might also indicate worn-out brakes.

On the other hand, if your vehicle smells musty whenever you are on the air conditioner, it might be signed molds are growing in the air conditioner.

The smell of clogged water can also signify excess moisture accumulating in the air filters or drain lines.

Final Thoughts

Your senses play a significant role in detecting problems in your vehicle.

Besides keeping an eye on parts that wear out, it’s also good to be alerted to any change of smell in your car.

A sulfur smell might result from a problem with the catalytic converter, fuel transmission, fuel pressure sensor, or a rotten egg.

Whatever the cause, ensure you contact your mechanic as soon as possible before the problem affects other parts.