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Problem with my cats. need good help...

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Old Mar 24, 2008 | 02:01 PM
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Default Problem with my cats. need good help...

my car has a very bad rattle whenever i hit a bump in the road/ when i start my car and let it idle. we put it on our lift the other day and started checking all the bolts and whatnot. we get to my cats and knock on them and it sounds like a baby rattle.

my mechanic said that they have probably expanded due to heat and wear.


i am getting a offroad y pipe with no cats and putting 2 cutouts on it this summer. but i have to keep the stock y pipe for smog checks. what can i do to get rid of this rattle for the time being?

thanks in advance
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Old Mar 24, 2008 | 02:20 PM
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They have fallen apart on the inside and thats the rattle you hear. Its all the honeycomb stuff bouncing around. Remove them is the easy fix, a shop wont do it for you unless you have a hook up somewhere. But if you cut them off you can remove all the comb in there and have them welded back in hollow.
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Old Mar 24, 2008 | 02:52 PM
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is this common on all 00+ camaros?
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Old Mar 24, 2008 | 03:38 PM
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GM extended the warranty on stock 00-02 F-body cats to 10yrs/120K, usually they'll throw the SES for P0420/P0430 inefficiency codes.
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Old Mar 24, 2008 | 04:15 PM
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i hope our local dealer can help me with this one because in the past, they havent really been helpful.
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Old Mar 24, 2008 | 04:28 PM
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yes it is the ceramic honeycomb inside...i had the same problem...mine was so bad that chunks broke off and flew back into my muffler,...so i had to gut the cats and take the muffler and pipes off to get the chunks out......if you are gonna bust up the insides..i highly suggest having a vaccum and face mask handy
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Old Mar 24, 2008 | 05:52 PM
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it sounds like a key chain being thrown around on mine.

so i just take my car to the local dealer and tell them to replace it?
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Old Mar 24, 2008 | 09:48 PM
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yeah if you just want them replaced,, if you have anything aftermarket on there i dont suggest going to the dealer......honestly i wouldnt go to the ealer at all. go to a specific race or muffler shop have them install high flow aftermarket cats, will prob still be cheaper then the dealer and better parts
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Old Mar 24, 2008 | 10:34 PM
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no my car is bone stock, besides rims and tires. will aftermarket cats still pass smog?
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Old Mar 25, 2008 | 06:54 PM
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if ur all stock i would check to see if ur cats are covered under warranty first,...if not then go the high flow route,...yes they should still be legal,,but b/c u are in CA I would double check I hear the CA laws are a bit extreme.......before you do anything check to see if the heat shield on either of your cats is coming off. They are just spot welded on and those welds break a lot and that can cause a rattle as well......make sure you check this b/c you can save a lot of time/money if its jst the shield....if so you can tack weld it back on if you have a welder,...but you dont really need the shield soo just use a flathead screw driver and a hammer to break the other welds and pry it off...just wear thick gloves you can cut your hands something nat on those cats edges
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Old Mar 25, 2008 | 07:28 PM
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thats what happened to my carsound cats i put on. They came apart inside and were rattling. Funny thing is it only came apart on the drivers side due to being the only cat banging the floorboard. It took maybe 2 weeks to come apart from the day i put it on. Id check the cats man
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Old Mar 26, 2008 | 12:08 AM
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well i went to the dealer today and my warranty expired december 10th of last year. and they told me new cats through them would be about 1 grand. freaking ridiculous.

any ballpark prices on hi flow cats?



i might just leave them how they are, because im going to be buying my new y pipe and cutouts soon. but i cannot stand that horrible rattle. to bad i cant gut them.
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Old Mar 26, 2008 | 04:15 PM
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A grand is ridiculous for a pair of cats, but thats a dealer for you. You can pick up a good pair of high flows for around $300 and have the local muffler shop install them.
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Old Mar 26, 2008 | 06:32 PM
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yeah i just put my head down and walked out. haha.

yeah im calling them as i type this. summer cant get here quicker.
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