1998 E320 Oil Leak

[Cleverpig]

I need help identifying the source of an oil leak on my 1998 E320 Wagon with 145,000 miles. The oil is leaking from the lower right (driver's side) front area of the engine somewhere above/behind the A/C compressor and below the hydraulic pump. The leak has been very slow for a couple of years but has increased in recent months to the point of pooling in the belly pan and depositing several drops on the garage floor every day. I have confirmed it is engine oil (Mobil 1 0W40). The oil runs down the A/C compressor and drips off of it and the transmission fluid hose that runs adjacent to the A/C compressor.

Several years ago I replaced the seals on the valve covers and oil collection covers and these areas are still clean and dry. My independent MB mechanic recently replaced the seal on the oil pan thinking that might be the source with no improvement. With the A/C compressor and hydraulic pump in the way it is impossible to see what is behind them that might be leaking. It does not appear to be the head gasket. With air flow off of the fan it could be leaking from somewhere near the base of the oil filter canister and blowing onto the A/C compressor. After reviewing some older posts it sounds like it could be the oil test port cover gasket or possibly something behind the serpentine belt tensioner pulley assembly.

Any suggestions would be appreciated since the Cleverpig is stumped.