Marbles...

chromeBuddha

Veteran Member
Joined
Jun 30, 2006
Location
Arlington, TX - DFW metroplex
TDI
2002 Golf TDI manual
Does anyone know what causes the exhaust to sound like their are loose marbles bouncing around in there?

A few months ago I was visiting NY and decided it was the perfect time to do a Diesel Purge treatment on my TDI. I spent most of the time with my head under the hood or sitting in the driver's seat revving through the RPM range. When I finished and cleaned up, a friend who had been working nearby commented that at points when the RPMs were high, the exhaust sounded like there were marbles bouncing around inside the metal... So here we are. Is this a sign that the catalytic is going?

What is the physical structure of the catalytic converter? I am somewhat familiar with those on gassers where there is a honeycomb that the exhaust gasses are pushed through. If there are fueling problems and you exhaust too much unburned fuel you can exceed the temp that the catayst can sustain and it can melt, closing portions of the honeycomb and restricting your exhaust usually leading to pretty clear performance issues.
 

Bran Diezel

Veteran Member
Joined
Jul 13, 2009
Location
Bristol, Va
TDI
On my 5th TDi - 2003 ALH 5spd Wagon
the brick in the converter can break apart and sound like a bunch of rocks in a tin can. also a loose heat shield can make a rattle sound. a broken hanger can make the exhaust hit the car and sound clunky. put it up in the air and bang on the pipe all up and down the exhaust to locate the noise. if you hit the converter with your fist and it doesn't sound solid then make sure if its inside or the outer shield.

this is for any car. i haven't paid attention to the exhaust on my tdi ;)
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Auburn, New York
TDI
2002 Jetta GLS TDI 5M
^^ x2. the cat internals is honeycomb "brick" structure. Possible that it could be broken up and rattling, but as above reply mentioned, get under and inspect the heat shield around cat and also hangars etc.
 
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