There's a lot of stuff right there at the front under the engine, between the radiator and the front of the engine on a '99 E300 - you've got the cross-pipe intercooler tube for the turbo shooting compressed air over to the intake on the left upper side of the engine. So, there's a lot of peeking and perhaps a mirror and holding of a flourescent trouble light to contend with too, to see anything down there. It's tight-quarters for sure on our car's front engine cavities.

Might be something - or might be nothing.......

My '99 E300's turbo sprung an oil leak, thereby filling the intercooler tube with engine crankcase oil when I was on the road working down in South Louisiana the year after buying the car new. It was still under warranty and spent two weeks at the Mercedes-Benz dealer in Baton Rouge, LA. waiting for a new turbo from MB. In that episode my car's diaper/green panels were drenched with oil, and warranty bought me new ones the dealer replaced at that time too.

The underside panels aren't necessary to have on the car, but they sure let the engine cavity on the lower-end stay very pretty and clean. This is the cleanest car I've ever owned and able to keep it pretty and clean top to bottom, and front to back. It's been 3+ years since I've had the panels off to perform an oil change on the car, (don't hardly drive the car at all for 10 years+) and it's about due, 10K miles on the Mobil 1, so I'll look around to see if I have anything like oil down there. Hope not.