Are these drain holes?
 

I found, on my E420, what looked like oily water, on the garage floor right behind the passenger side rear tire. There is a small , index finger size metal tube sticking down about 1/2" where this water dripped down. You can stick your finger up in this tube and feel a rounded soft rubber or plastic stop about 1/2" up. There is the same tube on the driver side. I then checked my 380SE and it has the same small tubes or vents in same locations, so I figured these must be some sort of drain tubes.

Is this correct? Appreciate your input. thanks

drain tubes for the cowl/windshield area. make sure they're free from leave, debris, etc. i usually flush mine out every few months.