Its not the injectors(cracked them all to no avail) not the vacuum pump (replaced it) new filters, good oil pressure. not the timing chain tensioner(replaced). possibly the chain itself? the stretch was not off much doing the basic visual inspection using the marks. the tensioning rail has side to side play however. what do you guys think?

http://www.youtube.com/watch?v=nXgBsmmVJlI

Its a 1984 300sd with about 200 thousand on it. The sound is there at all speeds and never goes away

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1979 240D with a 617 turbo diesel.

Sounded like something in the valvetrain to me.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

How are the valve clearances? Check the condition of the cam lobes, too.

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

when i went to do the valves i discovered that they all where recently adjusted.
The cam lobes appear to look good, i will take a closer look tomorrow.

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1979 240D with a 617 turbo diesel.

sounded like the timing chain slapping the side of the block. Is the chain tensioner working correctly.

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http://i148.photobucket.com/albums/s...titled-1-3.jpg
1981 300d

while trying do diagnose the sound, i fired up the engine with the valve cover off for just a moment. I wanted to see if the tensioner was working.(oil went everywhere!) The tensioner did not appear to move. It stayed in the same position it did when the car was off. I wrote this off because the car was idling. i figured it would kick in while the car was revved up.
when i replaced the tensioner, the new one only came with the housing and gasket. i had to use the spring and half of the old one.
How does one diagnose a bad timing chain tensioner?

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1979 240D with a 617 turbo diesel.