Rattling cat?

[arvy]

2002 Olds Silo (3.4 FWD). I noticed a rattline back in November just behind the area between driver & front passenger. I get a slight rattle when I tap the cat. Is my cat bad? If so, why has it not lit the check engine light? Thanks in advance for your advice.

[krugger]

2002 Olds Silo (3.4 FWD). I noticed a rattline back in November just behind the area between driver & front passenger. I get a slight rattle when I tap the cat. Is my cat bad? If so, why has it not lit the check engine light? Thanks in advance for your advice.

 

if there is a rattle in the cat, that means that the ceramic is already cracked, therefor you need to replace your cat, because if it starts to plug it can damage your engine. As for the light not coming on, I think it should but I am not sure why is not coming on.

[Chanks7]

I would say more than likely it is the heat shield around the cat or something stuck under the heat shield. If the cat was plugged or melted you would have a check engine light as long as the light works.

 

When you turn the key from off to on (not start) all the dash lights should prove out including the service engine light. Make sure it does.

 

I have had the ceramic in my cats crack before and they made no noise, did not hurt my performance or turn on a light. The only reason I knew it was cracked was when I removed them and shook them and a few chunks fell out.

[royg]

I had a 99 chevy truck that the ceramic broke i half and was restricting the exhaust. No SES light came on. The reason for the repair was that it had a lack of power and the cat was rattling.