I was wondering if anyone would be able to help me diagnose a noise in my 95 E300D. When I am on the interstate at speeds of about 70-80 mph everything sounds fine. That is, until I start to go up a hill and must put a load on the accelerator. I get a "knocking" noise from under the hood. Once I peak the hill and let off the noise goes away, and all sounds fine. It may be my imagination, but it seems worse when the temperatures are colder. I would appreciate anyone who can help me shed some light on this. It has been happening for awhile, and I'd like to try to get her fixed. Thanks!

Have you noticed any other symptoms? Oil usage? Smoke?

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Sam

84 300SD 350K+ miles ( Blue Belle )

E300DW,

Does the noise occur at the frequency of the engine speed?

If it does I would think an injector might be leaking and causing preignition.

P E H

Yeah it seems to occur between 3000 and 3500 rpm the most. As far as oil usage, I haven't noticed any. It probably wouldn't though b/c I change the oil religiously at 3K mile intervals.