B757 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 178
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
While conducting a Captain OE (Operating Experience) I was doing the exterior pre-flight and noticed a large area of oil under the left engine on the ground.  When looking closer I could see a large area of old oil dripping from under the cowling and could see active drips on the pavement.  I consulted with my OE student and he entered a log item in the ACARS while I called OPS on the VHF radio to have Maintenance come out to inspect the engine.   I then went back to the ramp level to speak with the technicians.  When the two maintenance technicians got to the plane; they told me the oil was from an over service of the engine.  They then inquired with the mechanic that did the ETOPS service check and he said he did not add any oil to the engine.  They then told me it was from the scupper and that it was normal leakage.  I was not sure that this was true and asked if they would open the cowling to have a look.  One mechanic opened the cowling and he just lifted it slightly but did not investigate beyond a cursory look and told me he would sign it off as it was fine and nothing to worry about.  We accepted the aircraft and flew to ZZZ.  As we progressed; I noted we were losing approximately one quart of oil per hour. During our five-hour flight our quantity in the left engine dropped from 21 to 16.  We made another log entry for our arrive at ZZZ.  After parking I went to the ramp level and noticed the oil was already pooling beneath the engine less than 15 minutes after arrival. I checked the maintenance action on the flight after our write up and saw ZZZ Maintenance found a broken seal on the left IDG (Integrated Drive Generator).  This is very concerning as the ZZZ1 Maintenance team placed us in a position where could have lost the IDG; engine and or created a fire hazard during a 180-minute ETOPS flight.
B767 Captain reported misgivings over lack of attention to an engine oil leak prior to an ETOPS flight by the maintenance team at departure airport.