What is this??? [Archive] - Bimmerfest - BMW Forums

: What is this???

10-03-2008, 09:44 AM
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?



10-03-2008, 10:50 AM
Looks like it could be a Vacuum line and I would say that it was definitely cut and a recent cut at that. Here is an excerpt from the Bentley manual that can explain some of the issues with that. See, "Air flow measurement and Vacuum leaks"

bimmer dot info
10-03-2008, 01:52 PM
It is for the PCV system. Just replace it with a similar size oil resistant hose and you will be good to go.

10-03-2008, 10:09 PM
make sure the pcv (positive crankcase ventilation) is not plugged up bimmer dot info is correct.....