After she warms up it starts, sounds like a can of marbles. No CEL, no performance issue, nothing loose I can see, I checked all of the heat shields. Any thoughts, one I have is cat's but ... Anyone have a similar issue ?

__________________
Ron
2015 Porsche Cayman - Elizabeth
2011 Porsche Cayman - Bond,James Bond
Sadly MERCEDESLESS - ALways LOOKING !
99 E320 THE Queen Mary - SOLD
62 220b - Dolly - Finally my Finny! Sadly SOLD
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
19 BMW X5 - Heaven on Wheels
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84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
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Is it possible that the Cat's substrate has actually broken loose from the can? I bring this up because this happened recently on my dad's F-150 and it had exactly the same symptoms. We narrowed it down to the cat by listening carefully, but nothing we did would get it to stop. Was still under warranty, so had the dealer fix it.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

panda, our 1998 E320 had similar symptoms. The rattling noise is caused by loose elements in the catalytic converters. I replaced the right assembly first, then the left side about 18 months later. If you have ramps, or a lift, it's a straightforward DIY job as the catalytic converter assemblies simply unbolt. The left side is more difficult due to the steering mechanism. I bought replacement assemblies from our local MB dealer, and gave them the old assemblies in lieu of paying a core charge. Expect to pay around $350 for each catalytic converter assembly.

If you tap on the catalytic converter assemblies with a rubber mallet when the engine is cold you should be able to determine whether one, or both, have loose elements. Or, you might try a stethoscope.

__________________
Fred Hoelzle

Thanks,I am leaning to that as the issue, may use a mechanics stethoscope next time I get her up on ramps

__________________
Ron
2015 Porsche Cayman - Elizabeth
2011 Porsche Cayman - Bond,James Bond
Sadly MERCEDESLESS - ALways LOOKING !
99 E320 THE Queen Mary - SOLD
62 220b - Dolly - Finally my Finny! Sadly SOLD
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
19 BMW X5 - Heaven on Wheels
14 38HP John Deere 3038E Tractor -Mean Green
84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
81 380 SL - Rest in Peace

With the engine off, use a rubber hammer / board to hit the exhaust near the cats and listen for noise. Don't hit the heat shields directly as you don't want to crush them.

+1 Cats. This is the standard W210 death rattle. Hopefully, it's one and not both. And hopefully the O2 sensors come out without a problem. And hopefully the manifold bolts cooperate.