2013 X5 E70 turbo 6 xDrive “power steering” whine sound…..solved

[HtownBlue]

For about a month I had a loud whine associated with RPM as tone would change with RPM. Tone would also change when turning wheel at idle. At Idle sound was present at lower tone. Very very very similar to power steering whine.
I bet money it was the PS pump. But before diving into that job I did a flush and replaced the reservoir which has a filter. Fluid was very clean as it was, and reservoir change did nothing. Sound still present.

As preventative maintenance I decided to purchase new belt and pulleys and tensioner, figuring I would be replacing the PS pump any ways.

Used a mechanics stethoscope and the noise was seemingly more present in the upper idler pulley, though I still could see a possibility where the PS pump was at fault as the noise reverberated to the lower portion of engine, and getting a sound stick on the PS pump while running is near impossible from the top.

Well belts and pulleys came much earlier than expected. So I figured I would do that job first and while having the belt off, I would start engine to confirm noise was associated with something connected to belt to eliminate much of the (in my opinion) foolish oil pump whine posts which people swear the whine is from an oil pump. Took belt off, started and no noise. Diagnosis getting closer to confirmed.

Then replaced the tensioner and BOTH the upper and lower idler pulley. Upper pulley definitely had some noise when turning it by hand, but still wasn’t going to call that a final diagnosis yet. Replaced and reinstalled and walked to front door to start.

BAM. No noise with new belt, pulleys, and tensioner. And the noise was completely gone. And it was absolutely loud and noticeable. It was not a typical higher pitched whine you may associate with pulley based noises. This was as close to a power steering whine as one could get I’d bet.

Moral of the story, don’t just parts cannon a problem to death. Strategically and logically step forward one thing at a time to make a final diagnosis.

[StradaRedlands]

+1 for parts cannon!