Q: What causes a catalytic converter to go bad?

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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.

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