For the past several weeks, I noticed some oil spotting on garage floor after driving the '740'. Yesterday, left the garage failing to notice large puddle of engine oil. Upon returning from around a 75 mile roundtrip, and while sitting at a red light, noticed smoke billowing out back (not sure if this was from exhaust pipe or just heated oil on underside parts. When the car was parked and hood was popped, witnessed oil leak at engine block (front) and the appearance of leakage elsewhere. Recent maintenance (6 weeks ago) includes A/C Compressor replacement. Any connection? Any ideas on probable cause. Thanks for any assistance.