I don't see how adding one of those units could hurt if you were looking to reduce the amount of blowby your engine is injesting. The oil separators that MB installed, both integral to the air filter housing and the standalone type found on 240D's are pretty simple units without a real filter. The Provent offers a changeable filter and likely works better than any stock unit as IIRC they were designed for heavy machinery and trucks? I have heard they are not cheap either. RT

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