Oil Leak on 1997 W140 S320

[Mino Erhan]

Hi everybody,
Got a new one... problem that is.

Car has only 70K miles on it. I checked everything that I know to check. This is my 4th 104 engined car and this is a new one.
There is an oil leak on the front of the engine on the lower part. The oil is yellowish color. It seems to come from the electric air pump.
I checked, PS pump, coolant lines, water pump gasket, trans lines, oil pan and all seem OK.
I thought at first that it was one of the transcooler lines, which I replaced both when I changed the fluid out.
It doesn't seem to come from the main front seal either.
Does the air pump have oil in it and do they leak?
It is also strange that the leakage is very thin, almost mixed with water.
As always... any ideas are much appreciated.
Thanks