Gsus

Hi Everybody,
I am having the noise of like a loose stone inside the catalytic converter when the car is in D gear and stopped... and a buzzing noise when accelerates. I have to say that I have no any code in the computer, (only those ugly noises), is there the possibility that I can take out the entire catalytic converter piece from flex pipe to the resonator so I can see if a ceramic piece is loose and take it out?
If anyone has changed the Catalytic converter could you tell me where can I buy it in a better price?

Thanks a lot for you help.

Radco

First thing I would check is the Heat shield on the converter. If a spot weld breaks the shield will buzz, rattle and I'm sure a few other noise's
Please keep us posted and I am sure the gear heads will chime in with better info

donbrew

I am going with the flex pipe is breaking. There is a bit of collar on the inside of the flex that is the first bit to break before the hole opens up. You seem to be describing both symptoms.

If that is the case then you can get a new flex section on Ebay or your favorite supplier. US they go for about $60 + an hour labor at your local welder/muffler guy.

Gsus

I have seen that there is excess of vibration in the emission system from the flex pipe to the muffler, I tried to immobilize it and the rattle noise is not present, any idea of why Im getting that vibration or is it normal?, What I can think is that it is due the spark plugs that I have changed recently, I put it at .044.

Laco

Even with the vibration, you should not be hearing the cat rattle. Apparently the cat converters, (at least some of them used on HHR's) tend to come apart internally. Just went through that within the past two weeks on my 2007, which only has 39,000 on it. Sounded terrible, and I'm pretty sure the flex pipe was leaking some. Fortunately there is a US federal mandated warranty of some emissions components, for 8 years or 80,000 miles, cat converter included, so mine was replace at zero cost to me. The car runs so much quieter now, which is why I'm convinced there probably was a leak, most likely in the flex pipe. If your cat is coming apart internally, you might be able to hear it, by banging on the cat, when the car is not running. Can't help with the vibration!

Radco

Gsus, did you find anything yet? Please update when you do? Thank's