Blocked by not running the car up to temp so the crap doesnt get burnt off over a period of time (going to the shops for a 2 min trip), blocked by the internal structure being old and crumbled etc
I can email you pics of several cats ive seen that are stuffed
- melt down, blown out etc.
This is from
www.surefloexhaust.com.au
"The ceramic biscuit has hundreds of long pin holes that the exhaust gas must pass through. The ceramic biscuit is coated with precious metals which heats up until it is red hot. This burns off all of the pollutants which are contained in exhaust gases.
Catalytic Converters eventually clog up, crack up and rattle, or melt down. They normally last for around 100 000km before they begin to effect the performance of your car."