Exhaust/Cat Removal Questions & Gaskets

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campbmic
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Exhaust/Cat Removal Questions & Gaskets

Postby campbmic » Tue Apr 02, 2019 5:43 am

I have a 2008 Pathfinder with 140k miles. Last month a CEL turned on and I took it to Autozone and they said a catalytic converter failed. I also noticed a loud rattling coming from the exhaust.

I took it to my mechanic and he said it was the driver side front cat that failed. Apparently when it failed pieces of the cat or something else got shot down the exhaust and are stuck in the muffler. This is creating the rattling noise that sounds similar to a busted bearing.

So I plan on disconnecting the exhaust from the headers, replacing the cat, and trying to knock out whatever is stuck in the muffler. Then reattaching the exhaust (with the new cat).

It seems pretty straight forward, just use a ratchet to disconnect the bolts. I wanted to see if there was anything I need to look out for or anything that could make this a lot harder?

Also, I received some gaskets with the new cat. However, I'll probably need to disconnect the muffler from the midpipe. Is there any gasket there? Can I use some all purpose gasket epoxy or what should I use?

Thanks!


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smj999smj
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Postby smj999smj » Tue Apr 02, 2019 9:55 am

Yes, there is a gasket there and you'll need to replace it. But, here's my issue with what the mechanic told you: if the front converter broke apart, debris would get stuck at the front of the downstream converter on that bank and wouldn't be able to get to the muffler, unless the downstream converter has previously been gutted or eliminated with a "test pipe" or a Doug Thorley mid-pipe or similar. If the rear converter is intact, than perhaps it's debris from the rear converter that has gotten into the muffler? You might need both converters on that bank.


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