Exhaust rattle

[Cruisineasy]

I have a 2011 31' Jayco Greyhawk Class C.
My catalytic converter was stolen so I made a straight pipe to replace it for the time being.(I have the new cat. but don't want to install it for fear of it being stolen again) All bolted up fine. Now I have a rattle at about 1500 RPM. its in the exhaust almost to the end. I checked the whole run and nothing is cracks or touching anything it shouldn't. Any suggestions??

[Gjac]

Cruisineasy wrote:

Gjac wrote:
Could also be a rusted/loose baffle inside of the muffler, at lower RPM it is more noticeable.

Must be this. Nothing else appears to be loose or cracked. It rattles at 1900 to 2100RPM only.

If you hit the muffler with a rubber mallet you should be able to hear the rattle.

[Cruisineasy]

Gjac wrote:
Could also be a rusted/loose baffle inside of the muffler, at lower RPM it is more noticeable.

Must be this. Nothing else appears to be loose or cracked. It rattles at 1900 to 2100RPM only.

[Gjac]

Could also be a rusted/loose baffle inside of the muffler, at lower RPM it is more noticeable.

[klutchdust]

My first thought was go and check what piping you replaced. Loosen and readjust the clamps and where the pipe goes into the manifold.
I had a hairline crack in a bracket that supported the exhaust up near the manifold.Rattled once it warmed up. Cross bracing on another vehicle.

[Grit_dog]

Doubt it has anything to do with removing the cat, unless you disturbed something else or are putting the exhaust under stress from being hooked back together in a different alignment.
Is it only under load or no load too? If no load, should be eas to find the rattle.
Crawl up under it while someone holds the rpms at rattle speed.

[jdc1]

After installing the new CAT, weld a few pieces of rebar crisscross to deter thieves.

[Cruisineasy]

No. Hayward Calif. Aww man. Checked everything I could find except the muffler heat shield. I'm bringing it home next weekend. Will check it then.. Hopefully it's not a Harmonic rattle.

[midnightsadie]

Hayward like in Wis? inlaw had a cabin on Teel lake loved fishing there. rattle see if theres a heat shield on the muffler ,might be loose.been 20yrs since I was there.

[MDKMDK]

Harmonic rattle. Probably due to missing catconv.