If the amount of crud in the bottom of my 220D's oil bath air cleaner is any indication, it does a much better job than a paper filter.

The oil bath filter doesn't work on a particle vs hole size principle -- it actually mixes oil with the air, and then removes the oil. All the dirt sticks to the oil,and collects on the bottom where it stays. They really do a very good job if they have the correct amount of oil in them.

Note that if you have blowby issues, they will get overfull from oil draining down the intake hose. Better than blowing it into the engine, which is where it goes on engines with paper filter....

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!