They are probably the old oil-bath filters with a dry filter conversion. At least, they sound like it. I had the oil bath filter setup, and I removed it when I installed my new turbo'd engine. The PO of my bus carefully cleaned the wire mesh filters and ran them dry, and the engine was ruined. The gritty oil sludge was caked 1/4" thick on the inside of the air box, a whole new meaning to the term "dusted". I have heard different things about just putting a dry filter in the oil bath housing but really don't know. My advice on removing the air filter connection (I actually said to pull the top off the blower and check inside) was kind of run it till you get an answer, 5 or 10 miles maybe. It's kind of a toss-up which is worse, running with faulty clogged up filters or running with no filter for a few dozen miles. If it were me, what I'd do is what I did do - rip out the stock air filter setup complete and install the biggest Donaldson ECO that would fit. Mine kind of sits on the muffler cover and takes up the whole space beside the engine on the driver's side. But I am glad the problem has found a solution!
Brian