it sounded a bit gay he he, but you have to excuse my english, i'm from norway. I can't give you a spesific hose to try out, but if you locate a black hose comming out from beneet the car, it's probably the one. I ain't familiar enought to say specific where to look. On my previous 280 SE it's sticking out on the right side of the engine.

Mercedes560sel
NORWAY