How can I check if a catalytic converter is good or bad?

Question

I have a Geo 92 and didn't pass the smog inspection. the guy said that it didn't pass because it was getting hot and the emmisions were to high--the radiator fan didn't work and caused the overheating. He also said that the CAT converter could be bad... which can also cause high emmisions ...is there a way to check if it works or not,, how can you tell...?

Thanks

Answer 1

get under the car and TAP on the cat with a hamer, if you hear anything rattling, your cat is shot.

Answer 2

with a non-contact thermometer the outlet of the converter should be a minimum of 100 degrees [F] hotter than the inlet. also if you drop the head pipe temporarily and notice a large increase in power it is a pretty good sign that the converter is bad

Answer 3

Typically bad cat converters will make a rattling sound if you shake them, as all the material (ceramic) inside is broken up. You could remove it and shake it to see if it rattles or not.

Answer 4

drive the hell out of your car at night ,then look up under the car and see if the catalytic converter is red or glowing then you can tell

Answer 5

If your car has more than 100K miles than you should replace the converter... they usually last only 100K miles.

Answer 6

well, actually you did have it checked apparently, no there really is no way to test it, you can physically get down there and check it out.....just replace it, its not expensive