my car has an oil leak that is driving me crazy

we cannot see where it is coming from

today we were working on a water system gasket that is to the right of the water pump and we have a lot of the stuff out of the way and still cannot see where it is

must be low on the engine and now we can see it is definitely coming from somewhere low on the passenger side area, that is where the most oil is
but we cannot see it from underneath

the 2 trans lines right there have a good bit of oil on them and that large hose underneath/next to them but it is not trans fluid, definitely oil

mech is thinking possibly blow off oil-not sure that is the right term??

i do have the egr delete mod and i read on some of the 06 cdi stuff some of them were possibly having blow off oil with their egr delete mods

anyway it is not like i have to add much oil often but i hate a messy motor and would like to solve this problem if possible

any ideas would be greatly appreciated

thank you

__________________
Courtney
2006 E320 CDI
2008 ML320 CDI