Foam Filters Make Little Sense for Air Intake

Probably the biggest takeaway from our report is the surprising prevalence of deteriorating foam oil filters on sailboats.

More than one-third of the sailors we surveyed had at some time in their past discovered foam air filters that had been sucked into their engine (presumably in tiny bits at a time). The engine will usually continue to operate despite this abuse, but noise and fumes will increase and longevity will surely be reduced.

1. 1. Someone left this foam filter untouched for years until it disintegrated. A good portion of it undoubtedly wound up in the engine.
   2. High heat from the crankcase vent melted the foam on this air filter. The burned hole renders the air filter useless.
   3. Some of the participants who discovered that the foam filter had disappeared from their original air cleaner decided not to replace it. The filter shown here is common to several models of Westerbeke marine diesel engines.

Related post: In Search of Better Filters