I think checking for bent pistons or jumped chain is a little premature. Can you give more details on the exact sequence of events that lead up to the engine noise? Did it have oil pressure when it was making the noise? Did you check the oil when it started making the noise? Was it full? Where on the engine is the noise coming from/ Front? Back? High? Low? Can you post a video of the engine making the noise?

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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