UNderdog

I have a 2008 S65 and developed a slight whine coming from what seemed like the driver's side front. Car has 82K miles. Whine was RPM dependent. From various sources including significant online research I decided it was the pressure damper on the tandem pump. Most everything I saw online discussing ABC was related to the older cars which I believe is ABC I. On ABC II cars the damper is on the tandem pump. Saw one post related to V12 engine ABC II where the poster said a dealer told him the entire pump needed to be replaced because the damper was not a separate part. My indie said damper is replaceable but the pump needs to be loosened to remove it b/c the head is in the way. Long story short, on ABC II V12 cars (2007-ish on I think) the damper is easily removed and replaced without removing or loosening the pump and after I replaced it the whine is gone completely. WIS says to remove pump and turn it so the damper is facing down while removing so no dirt/etc contaminates the fluid. I used compressed air and cleaned around the area before removing and replacing the damper and it was simple work. I'm posting this because I did not find an obvious answer when I searched and the whine was very annoying. Car also seemed to be a bit jarring on bumps but could have been my imagination. The dealer told me there was no problem and not to worry about it! If anyone has a similar whine and wants to know I have the damper part number at my office and can post later.

biker349

thanks for sharing.