The freshly rebuilt 300D non turbo engine I just rebuilt is now leaking at the drip tube bottom o-ring. There is virtually no blow by in this engine and it did not leak there for the first few thousand miles. I have been told by an MB tech that these would leak even when the cars were nearly new.

Is there anything that can be done about this? Could the oil separator be clogged up, or something else causing it?

Thanks for your thoughts,