Hose twitch - PS or ATF?
 

Hose twitch - PS or ATF?

I noticed a strange hose twitching yesterday on our 2008 X3 3.0si (n52 engine). I think it's either an ATF line or a PS line, but haven't been able to get it up in the air yet. Anyone know which?

Here's a video from under the front bumper: BMW N52 Engine - Hydraulic Line Twitch

The line in the center with the quick disconnect showing periodically twitches up to an inch or so and then holds steady until the next twitch.

The hose twitch interval seems to be close to a belt revolution at idle. But when I carefully held a paper towel in the air gap between the running crank pulley and the hose, there was no physical interference from the serp belt or pulley. Has anyone seen this symptom before and/or know what it is?

ATF Line
 

Wow. That is very strange.

At any rate, realoem.com is very useful to finding answers to questions that you ask.

Look here as an example:
https://www.realoem.com/bmw/enUS/sho...diagId=17_0365