[youbarajs]

I have almost always experienced RPM fluctuation at Idle when turning the steering wheel to an extreme end (left or right). I raised this concern with the dealer several times, and after following up for almost one year, they advised me to try with other E90 models and confirm if its the same experience.

To my surprise, in most of the E90, I experienced a bit of RPM fluctuation at idle when turning the steering wheel to both ends. However, my car was having some whining noise also, so we decided to change the power steering pump and the assembly, with the OEM one (along with serpentine pulley). The whining noise was gone after the replacement but the RPM fluctuation stayed.

Now almost after 2 months, I hear some heavy and thick whirring sound at a random interval, which is not audible from outside but from inside the cabin. The sound is quite random, sometimes we hear it at Park, sometimes at drive mode or neutral or reverse but mostly when the AC is engaged the sound goes off. I mostly hear it during the cold start but a few occasions I have heard a similar sound after a good 40 KM drive (while parking).

You can't make out the sound from outside and it's definitely not coming from the power steering pump. Today when I tried turning the steering wheel to extreme end, I heard a similar sound, same thickness, loudness, and pitch. The RPM fluctuation was more than what I have noticed previously. Holding the steering wheel on extreme end we opened the hood to identify the source, but you can't hear it from outside, and it's definitely not the steering pump (or that area).

The car otherwise drives fine, the steering fluid is clean and filled to the right level and no visible leaks.

I have already done another round of bleeding today and have added CHF (again no visible bubbles).

Could someone guide me on what and where I should investigate?

BMW E90 328I A/T

[az335imsport]

I have the same issue or I think it is. Any updates from your side?

[youbarajs]

Originally Posted by az335imsport

I have the same issue or I think it is. Any updates from your side?

Steering Pump....no leak and everything seemed good.

Please change the whole assembly if you haven't yet. A good starting point would be to check the moist steering pump (oily) reservoir and/or steering fluids on the joints (reservoir to pump and back).

It was under warranty and forced dealer to change it (they changed it thrice), the last one is working well and no noise. However, on extreme left/right turn during idle, there is a noticeable change of RPM and noise, but that is the case with most of the E90's I have driven.