Air Venturi Compressor - First Oil Change and Insights

FWIW I use Coleman Powermate PX FULL Synthetic compressor oil in my AV compressor with good results. Did 3 oil changes so far and while oil was dirty each time, it was not black. I change the oil while it is still warm and elevate the compressor slightly to drain as much oil as possible. I use bottled filtered water with Purple ICE (no need for antifreeze as compressor is always indoors) and my temps are around 65C on fills to 4500 psi.When I bleed air after a tank fill, I get some oil but it is mostly light in color.

Just an update on mine......it's sick lol. The last time I topped off a 75cuft a couple of days ago the compressor changed tone (louder) for about 1 second about three or four times but kept compressing just fine. The sound seemed to go away at higher pressure. After I reached about 4000# I didn't hear it any more. What I did notice though is that at the bleeder it was putting out some black slug which was made up of oil, water particles and what I think is iron deposits because of the way it stains. It's almost a year old with approximately 15hrs of runtime (according to my records) so I called Pyramid today and discussed the issue with an AV tech. He thought it sounded normal and that the bottom of the filter has a empty space that collects any oil or water. He suggested that I pull the filter and clean the entire filter housing really well and change the oil. I did this today after work and found the space (well) that he's referring to really nasty which I already knew. The bottom 1.5" of the tampon was also saturated with the black substance. I got it all cleaned back up, replaced the filter with the original filter that I changed several months ago that still looked really good. I also changed the oil as well. I restarted the compressor and just let it run to purge all the lines and dry any remaining Berryman's carb cleaner in the bottom of the well. I then started loading the filter housing as well as my gold filter housing by plugging the hose with a dead head plug. After the compressor built about 2000# I cracked the bleed valve and had a little mist of black so I closed the bleeder and continued pressuring up to around 3000# then I heard that sound again at least two times. I checked the bleeder again and this time it was oozing out the black slug so I shut everything down. I took several photos of everything that I can share with the tech if he needs them but I'm 110% certain this isn't normal. To me I'm thinking that I'm getting some blow by and sucking up lube oil and its compressing and going on into the filter housing. I'm going to call back tomorrow and see what I need to do next. If anyone wants to see some photos or video send me a PM.

Jimmy