Hi,

I have noticed an odd noise coming from my 83 300D engine from time to time. Temperature does not seem to effect it, however, RPM does. I had a valve adjustment done, then drove the car to canada (~400 mi away), straight on the interstate. While up there it was nice so I had the windows down, and heard it for the first time. When passing through the 8-900 RPM range, through Id say apporoximately 1200, I hear this odd rattling noise, that sounds almost like when you shake a can of spraypaint. Almost as if there was a loose bolt rattling in my engine. However, I think it must be something else, as that would be a constant noise, and I think that this is something that vibrates at a critical frequency that is reached in that RPM range, then subsides at higher RPMs.
Any ideas what this may be?
Any help would be most appreciated.
Thanks

JMH

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)