The cat on my 89 CRX Si is still working because I'm still passing tailpipe emissions. What I'm wondering is if the flow through the cat is reduced with age? I know when they quit working they can break up and clog the exhaust but what happens as they get older? The car has 225,000 miles on the original cat and I'm willing to spend the money for a new one if need be, but at the same time if I'm not losing anything with the original I can spend the money elsewhere. So what do you think? TIA!

 

They will either clog or break up. It hasn't broken up. If it's clogged the power will be down and the engine can run hot.

 

Dave-

Cool, sounds like I'm in good shape for now. Thanks!