Air Compressor ZT 75 Vsd

Dear All,

my company use 2 units of ZT 75 VSD Atlas Compressor. the problem is , we use our air compressor 1 unit at a time. after 2000 hours running, we will inspect and service the Air Compressor. the problem is, we found oil spill in the air compressor. currently , we don't know from where the oils spill came from. 2nd , does anybody who use ZT 75 VSD air compressor,got the same problem with our air compressor??

pls help me...