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I would like to ask about the expected life of a catalytic converter.

We had the one on our car replaced shortly after purchase (second hand) in 2007 due to a loud rattling noise. At the time we went for the cheaper after market option rather than the genuine part.

Almost two years later the rattle has returned and as they are not repairable we have been told the catalytic convertor needs to be replaced again.

We would like to explore with the service agent whether it is reasonable for a catalytic convertor to develop a fault after such a short time, but first we were curious to know if there is any benchmarking done of the expected life of automotive parts/items.

Nicci

From the "Ask Jack" archives - 27 January 2010

I have to say it is unusual for a catalytic convertor to be replaced (due to a genuine fault) from my experience, so to have one develop the same problem within such a short time is quite unusual.

Over the years many catalytic convertors have been replaced (or in many cases simply discarded) for the wrong reasons especially when garages are trying to sort out rough running or performance problems (and in some cases when stones get lodged around the heat shield and cause a rattle).

I can believe there is a considerable difference in price between genuine and after market but the risks are certainly greater with the cheaper option. Warranties can vary between 6 - 12 months with aftermarket parts and it can at times covers parts only.

Fitting genuine parts you have a much greater chance of some assistance from the distributor if the convertor was to fail or in this case develop another rattle.

I would be seeking another opinion as to the cause of the rattle as there are thousands of cars driving around NZ with their original catalytic convertors still fitted. It is certainly not a common practice to have them replaced on a regular basis.

I would expect a catalytic convertor to last for at least ten years or 150K plus.