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Workhorse W22, Chevy 8.1l exhaust rattle/noise

V10guy
Explorer
Explorer
Good afternoon,

I went today and started my MH since it’s been in storage for several months and ran it. It’s a 2003 Windsong, Workhorse W22 chassis with the 8.1l vortec. Upon warming it up and driving it, after it was warmed up, I noticed a loud rattling noise at idle. I know the 8.1l have lifter noise, but this was coming out of the exhaust area...I couldn’t really hear it by the front of the engine or by the doghouse inside...but it was very loud out by the exhaust outlet. The only way to describe it is as a very loud rattle/vibration but at the cadence of the motor running. It did get slightly louder with increased RPM, sometime it would go away, then come back when you increase RPM.

It sounded like something is rattling in the muffler? Again, it’s very noticeable, I could notice it sitting inside as well.

Thoughts? I checked the engine oil, they’re where they should be. Could this be something internal to the engine and noise is coming out the exhaust?

Thanks,

Doug
Wife and I, 3 Kids(10, 9 & 6) 2003 Forest River Windsong 32' 8.1L Workhorse w/Allison. TOAD coming soon...
11 REPLIES 11

Chum_lee
Explorer
Explorer
With the exhaust system cold, slide under the MH and hit the catalytic converter with your hand or a block of wood. If it sounds like a can full of marbles, . . . . you need a new converter. If no noise, try the same thing with all the other components of the exhaust system. Eventually you will find the source of the rattle. Check all your exhaust hangers and heat shields too.

Chum lee

allbrandauto
Explorer
Explorer
my workhorse 8.1 had the same rattle was above the rear tailpipe heat shield at the end of the pipe

rgatijnet1
Explorer III
Explorer III
Just check there the exhaust pipe connects to the exhaust manifold. On each side there is a "donut" type gasket that is used for the seal. These are known to work loose and rattle. It is a simple and cheap fix IF you can get the bolts loose without breaking them. If you see any movement at this joint, spray penetrating oil on the bolts and let them sit overnight. Then you slowly try to get the bolts loose by turning them in each direction until they break free. Use more penetrating oil as needed. The gaskets should be available at any auto parts store.

V10guy
Explorer
Explorer
Thank you all
Wife and I, 3 Kids(10, 9 & 6) 2003 Forest River Windsong 32' 8.1L Workhorse w/Allison. TOAD coming soon...

Fulltimers
Explorer
Explorer
Shimmy underneath and start banging on things. I found my muffler sounded like a can full of marbles once. It didn’t make any other noise though. Maybe just slide under with it running and see if you can pinpoint the noise.
Fulltimers
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angler
Explorer
Explorer
Yes. Hopefully it's a shield. Known for exhaust manifold bolts breaking.
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Executive45
Explorer III
Explorer III
Remove the doghouse and check to see if it's coming from the engine compartment or underneath. If all is ok up top, stop by a muffler shop and have the exhaust system checked for leaks.....Dennis
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1968mooney
Explorer
Explorer
Could be a baffle in the muffler rusted loose over time.

V10guy
Explorer
Explorer
enblethen wrote:
Heat shield around catalytic converter?


Will definitely check. Thanks.
Wife and I, 3 Kids(10, 9 & 6) 2003 Forest River Windsong 32' 8.1L Workhorse w/Allison. TOAD coming soon...

camper_ron
Explorer
Explorer
Could be an exhaust leak they are known for that.

enblethen
Nomad
Nomad
Heat shield around catalytic converter?

Bud
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