Just recently purchased my 91 525i m50 from a "shady" dealer here in Germany. Ive been replacing a shopping list of things lately and came across this while I was swapping in a new MAF.
There was a disconnected hose going between the two connections in the following pics. Once connections is right by the oil dipstick while the other is on the bottom side of the intake elbow. The third picture is the hose that was on it. Shady thing is the hole you see on the hose looks like it was sliced, not worn, and it was facing the bottom.. Makes me wonder if the dealer did it on purpose to get me to bring it in to his shop.
Anyway, can anyone tell me what this hose/connection is for?