Back pressure leakage that happens to ALL screw compressors called the "Blow Hole"
The Blow Hole will get bigger over time.
Cause by wear and tear of bearings.
Overhaul and replacement of bearings is a must! & cannot be avoid?
Typical RESULTS could be;
* Air-End will operate at hotter and higher temperature!
* FAD will be lesser and lesser!
* Oil & Air leak all over!
* Sometimes humming sound
* Higher Current consumption