MPeezie4

I have a 2000 ML320
It seems to be louder nowadays when its started up. When you turn the wheel it makes an even louder noise (reminds you of the old power steering fluid is low issue) but I don't think that is what it is, because the reservoir is 3/4 full. Its loud and embarrassing , so any ideas on what this could be?

psnevets

How does the steering feel when you hear that noise? Is it exceptionally burdened or jerky feeling? If so, your rack may be failing, at the worst case. If it doesn't feel wrong, maybe just a dose of belt dressing will temporarily solve the issue until you change to a new quiet belt.

art_arev

Your reservoir is busted...... The whinning sound happens when the diaphragm inside the reservoir is torn due to air bubles........