Many diesel engines have a warning to never overfill with oil as serious damage can result. (Usually a sticker.)

A diesel can literally feed off its own oil and go into runaway. (If you do a search on "runaway", you will be in for an eye-opener.) Runaway is where the engine is capable of going to wide open throttle until it siezes.

You should be all right once the level is corrected.

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Sam

84 300SD 350K+ miles ( Blue Belle )