Recently my 300D started making this rattle only at idle or a few rpms above idle. When I rev the engine a little more it goes away and I hear the normal clatter of the diesel. Does anyone have any ideas? Could it be a stretched timing chain? The sound emanates from where the timing chain cover is when I listen with the stethescope.

I just eliminated a rattle yesterday but it was coming from the air cleaner assembly at idle. The bracket for the trans cable that bolts to the valve cover was hitting the side of the aircleaner. I slit a piece of vacumn hose and put it over the edge. Nice and quiet now just a thought HTH Mike

Chain rattle is not a known common on this engine as it would be on a V-8. Much more possible is the serpentine belt tensioner assembly. It bolts into the timing chain cover. If its cocked, replace it. The belt shock may need to be replaced - dealer shocks cost more but last noticably longer. Finally, if the tensioner screw works its way loose, it will tear up the timing cover and that's $$$ to fix.

HTH,

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Brian Toscano

I just finished chasing down a rattle in my 92 300D 2.5 it was the belt tensioner shock. It was quit loud up to about 1000 rpm then noraml engine sounds. I also replaced the belt. My rattled sounded like it was coming from near the power steering pump. Don't know if there are related but it is cheap to check. I removed the belt and started the car for just a little bit. The rattle was gone so I know it wasn't internal to the engine. Good luck