Q: Is there a smell which develops in a car when the catalytic converter starts to go bad?

asked by on

About one week ago, a strong unpleasant odor developed in my car. It just started one day; nothing I can think of was the cause. I had my local tire shop put the car up on their rack to inspect the underside chassis for maybe a small animal nest. Found nothing inside or out. A gas station attendant I use on a regular basis thought the smell (rotten eggs) might be the start of trouble with the catalytic converter. Any truth to that claim?

My car has 147500 miles.
My car has an automatic transmission.

Hi there. If there is a rotten egg or sulfur type of smell then most of the time this is caused by a failure in the catalytic converter. When these fail and become too hot they will smell like this. It needs to be tested with a temperature gun or with a back pressure tester. Both of these will help to identify this as the problem. A cylinder misfire will also cause this to occur. If you want to have this exhaust smell diagnosed, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Is there a smell which develops in a car when the catalytic converter starts to go bad?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brake fluid replaced, now car will not stop unless brake pedal is nearly to the floor.

One of the most common causes of the brake pedal going to the floor is a loss of brake fluid. Generally, this is easy to detect due to the fact that there is usually brake fluid leaking on the ground...

Q: How can i recode my pontiac g6 2006 key lock cylinder to my key without the old ignition key lock

Hi Albert. I don't think it's possible to recode an ignition cylinder without the proper security software, which is only available through a dealer these days. You could replace the ignition cylinder and have a new key as an option....

Q: Engine occasionally misfires

Hi there, thanks for writing in. In most cases, if you have an error code show up, make the change of components and don't reset to the error code with a digital scanner, the issue will still continue. This is...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...