I got that same sound a few days ago, and checked the power steering fluid level and, sure enough, it was very low (barely touches the bottom end of the center dip stick). But, that's the "cold" level. Not sure how much it would've risen after driving it hard.
tibra1, the filler cap has a vent hole on it, through which the fluid leaks. Happens a lot to cars that get tracked (or, otherwise, driven hard) when the fluid heats up/boils. So, a lot of us keep the cap covered up with a towel & ziptie.
Anyhow, in checking the fluid level, and I was taken back by the color of the fluid, as follows (excuse the sh*tty iPhone picts). First is before filling it up, and second is after (& driving around for about 15 min's).
A mechanic and a SA (these 2 people at 2 different BMW dealers) told me that the discoloration is due to cavitation (triggered by low fluid level). Taking the car in for inspection in about an hour. Will post findings/results/assessment.
BRP 1:56 |
CVR 2:01 |
ACS 1:53 |