Hi All,

My Universal M35BC diesel came with a crankcase blow-by vent tube routed to the air intake.  I understand that this arrangement is ideal for capturing smelly crankcase fumes and routing them thru the engine and thus out the exhaust.  I’ve heard of some concerns regarding run-away engines using oil infused blow-by gasses but my understanding and experience with my own engine suggests that, for what ever reason, that does not happen.

My only issue with my current set-up is that my engine blow-by has sufficient oil mist infused in the gas that it saturates the foam air filter and drips into the bilge.  My bilge is always an oily mess.  I use oil absorbent mats below the engine which float in the bilge water but this oil gets everywhere.  I’m also concerned about the degree to which the oil saturated foam air filter is impeding air flow into the combustion chamber.  It seems to me that this is not an ideal arrangement.

And so, I’m exploring the option of installing an oil catch can along the length of the crankcase blow-by vent tube.  Amazon has a number of these for sale for around $30 bucks.  Many of these have an air intake air filter mounted on top whose purpose I don’t understand.  Perhaps in a sealed system this allows for air pressure equalization.  Mine, of course, is not sealed and is open to atmospheric pressure at the air filter and so this small air filter would be unnecessary, I think.  Do any of you have any thoughts or recommendations on this general topic?
Thanks,
John