Smells aren’t just bad for your nose; they could mean bad news for your car. Like tire tread, those car smells are trying to tell you something—and you should listen. But, which smells requirement immediate care?

Musty or Gym Socks

If you notice a musty or gym sock smell, especially while running the A/C or Heater, it’s probably mold. Mildew and mold grow in the water from the condensing process in your A/C evaporator.

Luckily, the fix and prevention is simple. About a mile from home, turn the fan onto high and the A/C off to dry out the system. If that doesn’t work, you may want to look into cleaning your A/C system as breathing in mold and mildew can have adverse health effects.

If you continue to smell the musty smell, check your door seals for leaks as your carpets could be getting wet.

Sweet or Maple Syrup

If your car smells like maple syrup and you haven’t been eating pancakes, you have a leaking antifreeze issue. The leak could be anywhere in your coolant system—radiator, heater hose, gaskets, etc.

The sweet smell is coming from the ethylene glycol, a toxic chemical. You will want to get this sweet scent checked out immediately.


A burning smell is never a good sign. But, what material is burning?

Burnt Oil

Burnt oil smell means an oil leak somewhere in your system. The oil from your engine is touching a hot part of your engine. Check your parking spot after idling for a few minutes to see if there is any oil left behind to determine the severity of the leak.

Burnt Carpet

Overheated brake pads and rotors will often smell similar to burning carpet. If you haven’t been driving steep mountain passes, it’s time to get your brakes checked.

Burnt Paper

An appropriate smell if you are sitting in stop-and-go traffic. The scent of burning paper means a worn clutch or overheated clutch plate from riding the clutch.

Burnt Rubber

Something is up with your hoses. Perhaps a belt is slipping. Or a belt is getting chewed or rubbing against a moving part.

Burnt Toast

This screams of electrical issues—which means a stop at the mechanic ASAP. Something has short-circuited or overheated.

Why the immediate inspection? Electrical issues are a huge fire hazard and a leading cause of car fires.

Rotten Eggs, Hell, and Sulfur

No. You aren’t in the worst part of Dante’s Inferno. However, something is wrong with your catalytic converter. Your vehicles catalytic converter is responsible for converting hydrogen sulfide in your exhaust to sulfur dioxide. For some reason, this sulfur dioxide is too potent, or it’s not being filtered out/removed correctly.


If your currently filling your tank, a gas smell is to be expected. In fact, if you can’t smell gas you may be doing it wrong.

It could be that your gas cap is too loose or missing. Perhaps, your evaporative emissions control system isn’t recirculating fuel vapors properly. Or worse, you have a leak in your fuel system. Like electrical issues, you will want to get to the bottom of the gas smell ASAP as it is a fire hazard.

Rotting Fruit

Luckily, these car smells are easy to identify—somewhere in your car fruit is rotting. Maybe you are missing a few bananas from last weeks shopping trip. Check under your seats.

In conclusion, from sweet to sulfur, car smells are trying to tell you something. Some may be simple fixes like removing rotting fruit, while others may be complex and urgent like electrical and gas leaks. All smells should be taken seriously. To schedule an inspection of your car smells, call Northwest Auto Center of Houston at 281.894.8880.