I have an old 2000 Honda CRV, where the 18 year old exhaust is on its last legs and in need of a full replacement. The B-pipe bolt mount on the catalytic converter has rusted off, and the cat heat shield has also rusted off. The B-pipe is currently directly welded to what remains of the old cat.
The vehicle otherwise runs fine, so I will probably get a new cat, heat shields, B-pipe, etc from some online place that sells inexpensive genuine Honda parts.
Apparently the A-pipe is not leaking so probably will keep that, as it costs nearly as much as the cat and it's just a short little stub of a pipe.
I see the oxygen sensors are about US$250 each and there are two of them, one on the A-pipe and one on the cat.
If the vehicle is running fine as it is now, and the check engine light is not on, is it necessary to replace the oxygen sensors with brand new as part of installing a new cat, or if they are working fine already, pull them out and reuse them?
I am aware the threads are likely seized and may strip trying to remove it, but seems worth trying, to save $250 vs a new O2 sensor.