I just bought a 2002 Saturn SC2. When I shut the engine off I hear this ticking noise from under the car. I was told that it is the catalytic converter. I was just wondering what I can do to get it to stop.

your exhaust gets really hot after driving for a while, so lots of things expand and contract while they change temps, i thought this was normal for all cars, unless its an excessive ticking noise, my 96 sc2 does it all the time, so does my moms jimmy.

will it happen when you don't use the A/C? if no, there is a kit for this, otherwise, torque the exhaust systems bolts/nuts to spec is all you can do.