Catalytic Converter

I had my passenger side catalytic converter replaced at 71,000 miles last January while it was still under warranty. It was found to have an internal fault, probably from leaking valve cover gaskets, which were also replaced. Now, at 92,000 miles, my check engine light came on, and I have been told that the driver side catalytic converter needs to be replaced, and it is no longer under warranty (8 years or 80,000 miles). A mechanic told me that catalytic converters should always be replaced as a unit. If that is the case, should the dealer have replaced the driver side CC when the passenger side CC was installed? BTW, I have done all the recommended maintenance over the years.

You normal warranty is long over. Dealers (Honda, right?) are NOT required to replace any emissions parts failures unless and until the car fails a state mandated emissions test inside that 80,000 limit. They are NOT going to eat two converters unless they MUST under the law… Car companies don’t voluntarily install $1000 parts “because it’s the right thing to do”. They only do these emissions repairs because they are FORCED to to them by law, and they will follow the law to the letter…If one converter cured the previous problem, then one converter is all you get…

I suggest getting a second opinion from an independent mechanic. Too many catalytic converters are replaced when something else is the cause of the problem. Faulty O2 sensors come immediately to mind.

There are LOTS of cars out there with 150,000 to 200,000 miles still operating with their original catalytic converters. Yours should not need replacement at only 92K unless there is some other problem.

What is the Audi dealer claiming has caused the second failure?

If the trouble code said something like “Bank 1 (or 2) catalytic converter operating below threshold” it does NOT mean the cat is bad. There are other components which should be tested first to make sure they are not causing the converter to work below threshold.

Get another opinion before you buy an expensive cat.


Try as I might, I can’t make a connection between leaking valve cover gaskets and a catalytic converter. Leaking valve cover gaskets would allow oil to leak out of the engine, and that might make a mess, but it would not affect the cat.

You’d have to be leaking something INTO the engine to potentially affect the cat.