How do you change the o2 sensor in a Volvo 240 dl?

the o2 sensor is located in the exhaust system, protuding from the catalytic converter. to replace the sensor u need a sensor socket of the rite size (they usually all only come in one size). Its a socket with a slot cut out of it for the wires to fit by when loosening the sensor. Its prolly easier to remove the whole exhaust system out since its only held by elastic bands, but u can do it with it attached as well. Loosen sensor with sensor socket, remove and replace. Oh and one more thing, remember to do this when the car hasn't been started for at least an hour or two otherwise that exhaust will scold u bad.