How do you change a Volvo 240 catalytic converter?

Working on the exhaust system is a job best left to a professional. You will save very little by doing it yourself. Have the catalytic converter tested to be sure you need a new one. Catalytic Converters are very expensive so you do not want to replace a good one. If it is bad you need to find out why it went bad. Things like a miss on a cylinder from a bad plug or a defective O2 sensor will ruin the converter. Also a burnt exhaust valve will destroy the converter.