ytech15, call Mike Strickland (Service Director at MB of West Chester) at 484-313-1111 and ask if there are any techs still working there that are intimately familiar with the M104 engines. My timing chain tensioner diagnosis was at least 12 years ago so those skilled techs may be retired now.

Our M104 engine had a "slapping sound" with a slight RPM increase above idle. The more I think about it, due to the timing chain tensioner not building up enough oil pressure to keep the timing chain taut.

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Fred Hoelzle