From Jalopnik · Chloe Clougher · · 1m 40s
Why Cars Smell Like Rotten Eggs
Catalytic converter failure, transmission leaks, and battery issues cause rotten egg smells in cars.
In brief
Catalytic converter failure, transmission leaks, and battery issues cause rotten egg smells in cars. Rotten egg smells in cars often indicate catalytic converter failure, transmission leaks, or battery leaks. Originally reported by Jalopnik.
Rotten Egg Smell in Cars
Cars can emit a rotten egg smell due to several possible causes including catalytic converter failure, transmission leaks, or battery issues.
Catalytic Converter Failure
A clogged catalytic converter can cause a rotten egg smell as it fails to convert hydrogen sulfide into odorless sulfur dioxide.
Catalytic Converter Costs
Replacing a universal-fit catalytic converter costs $200 to $300, while direct-fit replacements can exceed $2,000.
Check Engine Light
A failing catalytic converter often triggers a check engine light linked to a P0420 code.
Fuel Pressure Sensor
A faulty fuel pressure sensor can cause excess fuel to reach the catalytic converter, creating a rotten egg smell.
Fuel Pressure Sensor Costs
Replacing a faulty fuel pressure sensor costs $250 to $400, depending on the car and garage.
Transmission Fluid Leak
Leaky transmission fluid can emit a pungent, eggy odor due to sulfur content in some fluids.
Transmission Fluid Costs
Fixing a transmission fluid leak costs a few hundred dollars, much less than replacing a transmission.
Battery Leak
A leaking battery can emit a rotten egg smell from sulfuric acid.
Battery Costs
Replacing a standard battery costs up to $200, while premium AGM batteries can cost double.
Preventing Smells
Avoid long stationary periods, extreme temperatures, and keep batteries clean and secure to prevent sulfuric smells.
At a glance
Rotten egg smells in cars often indicate catalytic converter failure, transmission leaks, or battery leaks.
