Hello everybody. I have an issue with my air compressor Sanwa, piston, 3 stage. All bearings and piston rings were changed during DD. Honing also was made. Is it normal that oil is getting little bit dark? When I opened crankcase I found some black substance on the bottom surface, something like paste.

Hello, neck7281.Could the dirt be from the overhaul i.e. not cleaning out the oil system? How many hours since the o/h? Is there any water in the sump? Microbial contamination is more like a jelly than a paste. I would clean out the sump and change the oil but keep a sample to send with your other LO samples for analysis. Check the crankcase breather is clear. Is it running any hotter than previously?

Thanks for your reply! All dirt was cleaned. I'll check about hours. There was no any water in the sump. I've already cleaned sump and changed oil, will see. Temperature is also within the limit. Could it be piston rings or big end/small end bearings running in?

Unlikely to be from the bearings, certainly hope not; rings/liner a possibility. Was the oil changed 50-100 hours after the o/h? Is it the correct grade of oil as specified? Is the black paste attracted to a magnet?

I have problem with tanabe air compressor, there's come condensate water in sump daily.And now from auto drain trap continuous air flow when running.
Any thoughts will be highly appreciated

I have problem with tanabe air compressor(h74), there's come condensate water in sump daily.And now from auto drain trap continuous air flow when running.
Any thoughts will be highly appreciated

If it has started since the overhaul are you sure that it is not cooling water? All genuine Tanabe spares used, including gaskets and O rings? Re-check torque of head bolts, cooler covers. Is the 1st stage cooler leaking? Any air bubbles in the cooling water sight glass? If it is condensate is the compressor operating in high ambient humidity? Crankcase breather clear? Is the water separator working even though it is continually blowing down? Fix the air leak first; there is probably something stuck under the seat or check the solenoid then set the timer and interval to keep the bowl empty without wasting air. Clean out the sump and check for water leaks with the cooling water on, look for any hairline cracks in the casting. Cooling water inlet no lower than 36 deg.C (LT cooled?) and no more than 10 deg.C rise on the outlet. Use the correct oil. Good luck.