Q: What causes a catalytic converter to go bad?

asked by on February 28, 2017

Also what are some other things i should do to make sure my replacement catalytic convertor does not fail once again? In other words what do I need to do to my truck to make sure this doesnt happen again

My car has 60000 miles.
My car has a manual transmission.

Pursuant to Federal law, the Toyota warranty on the catalytic converter extends to 8 years or 80,000 miles. Therefore, you should contact Toyota for warranty service on your catalytic converter.


Converters fail due to mechanical impact damage, melting of the catalyst due to overheating, and/or contamination of the catalyst. The catalyst can become contaminated if the engine has internal oil leaks. The catalyst honeycomb structure can melt if the engine misfires consistently and unburned, raw hydrocarbons (gasoline) enter the converter and light off within the converter. The heat generated from such combustion well exceeds what the converter can withstand and the honeycomb melts.


In view of the causes, be sure your engine is not misfiring, that internal engine oil leaks (such as oil leaks past the valve stems) are minimized, and that your engine is generally in good running condition. If for any reason you have to replace the converter outside of warranty, Your Mechanic does offer that service, performed by a certified Mechanic, dispatched by YourMechanic right at your location. The service to request is exhaust system - catalytic converter replacement. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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

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

car shaking randomly at various times

Hi there. Typically when you don't have a fuel or ignition system component failure, a vacuum leak or loose motor mounts will be the source of this type of vibration. If you're having this vibration all the time, I would...

Windshied washer fluid

Hi there. The reason the windshield-washer fluid reservoir should not be filled with concentrates at full strength, is the concentrate is to thick and may plug the washer system. You can use de-icer fluids following installation instructions. These products should...

losing power

Hi there: In most cases acceleration issues are caused by restriction of fuel or air into the fuel injection system to be burned inside the combustion chamber. This could be the result of damaged mass air flow sensors, EGR valve,...

Related articles

A Buyer’s Guide to the 2013 Subaru BRZ
This This sports car for the everyday man or woman is an irresistible combination of style, handling, and just plain fun. The BRZ offers a respectably good time on the way to work or on the way around the race...
The Best Used Cars to Buy If You're a General Contractor
If If you're a general contractor, you probably aren’t in the market for a used car. More likely, you’re looking for a pickup truck, because you need to haul equipment and supplies to various job sites. Most contractors will likely...
The Best Used Cars to Buy If You’re a Painter
If If you’re a painter, and you work for someone else, chances are you don’t care all that much about what you drive, as long as it gets you to and from work reliably. On the other hand, if you...