Power steering whine: change the reservoir so you have a new filter.

[zellamay]

This is probably common knowledge for the pundits, so I'm posting this for those that don't know. I stumbled on this fix almost by accident, not on this site but on youtube. My wife's 325i, 182k, (would be same for Zs I think) developed the typical p.s. whine. I changed the fluid in hers and in my Z3M. Compared to mine, her old fluid was brown and watery. That fixed the problem for a few days, then noise returned. In searching about a new p.s. pump, I stumbled across the fact that the reservoir has a non-changeable screen and that sometimes a new reservoir ($25) fixes the problem. It did.

[solimans]

Sweet! Many thanks, sir


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[saneesh8]

Any bubbles in the reservoir..?

The odyssey i have, the suction side to the pump have a bad O-Ring which can cause the same issue. It was sucking air mainly when it is cold. Bubbles in reservoir was the easy way to find it. It also had the recall for this filter issue inside the reservoir.

[zellamay]

No, I've never seen bubbles. I always bleed immediately after doing anything: turn steering wheel all the way left, move it back and forth a couple of times, then do that on the right. Do that twice.

[nevan]

Thank you, sir!

Hey Brad,

Just wanted to let you know that the reservoir was starving my ps also. The moment it is replaced, the whining sound vanished.

Thanks so much for the information!!

[zellamay]

Hey Brad,

Just wanted to let you know that the reservoir was starving my ps also. The moment it is replaced, the whining sound vanished.

Thanks so much for the information!!

Wow! Mark this as a win for the home team. Why don't you post the history of your problem & attempted fixes so others can read it and learn?

[nevan]

Wow! Mark this as a win for the home team. Why don't you post the history of your problem & attempted fixes so others can read it and learn?

In a summary, I've been chasing the same whining noise on my e92 (n51b30, auto) for some time now.

The whining sound only happened in a range of 1000-2500 rpm tone changes with rpm even when parked (i.e., very refined noise unlike the squeak or rattle caused by ps rack, idle pulley, the closest comparison would be an amp with bad grounds) then disappears above 3000k (possibly too loud to hear it above the rpm, I thought. But from what I'm told the ps is variable, and it is less active at higher speeds which seemed more relatable with my case).

In terms of part guessing game played by the shop (thankfully the car was still covered by a warranty), I had the pulley tensioner and ps pump replaced (fluid flushed), but the whining still persisted. At that point, I moved on to suspecting others like AC clutch (but it was spinning quiet, both AC on/off). So I was starting to think perhaps there were possible air leaks making whining/whistling noise from vc or ripped ccv valve (which is on top of the vc on e9#) but I didn't get any obvious rough idle. At that point, my warranty luck ran out so I've taken a more cautious approach since then.

Frankly, I hadn't even thought of the ps reservoir as a possibility until I saw this thread. - I've started doing some more readings on ps starvation due to clogged reservoir filters, I've realized others were having very similar symptoms (and common oversight too, myself included). I've decided to test it by replacing the tank (because the reservoir has never been changed by the look of it), and see it would help as it did with others. To my present surprise, the whining was no more. And the e92 finally sounded like it was supposed to!

If I hadn't come across this thread, I probably would be still playing more guessing games with wrong parts/components even now. So thanks, zellamay. You saved my day!

[Updated]

Ok, so it seems I've come to a conclusion too soon.

The whining came back this morning. But I have a hunch that it is the fluid itself. While I was replacing the tank, I also noticed how muddy the fluid was with metal spackles (Perhaps the shop only top the fluid in the tank instead). I should've replaced the fluid altogether. Anyhow, I will order the 2 liters of ps fluid so I can flush them until they are clear using the turkey baster method.

But it is now just a matter of getting it done. Thanks again!

[zellamay]

Addendum: We bought an E90 (2006 330i) for my wife, that had a little pwr stg whine. Of course, replaced the reservoir/filter and bled via turkey baster method, but here's something new. There is not much info on the E90 forum, so I looked around and ran across a video on bleeding. It said the front tires should be off the ground and the engine off, and that you should turn right to left for many cycles. It worked. I don't know whether "tires off the ground" is better for our cars, but I'll do it if I ever have to bleed mine again.

[solimans]

I remember reading “tires off the ground” somewhere. Must have been TIS or bentley.

It worked well for me


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[Hoyt Clagwell]

I don't know whether "tires off the ground" is better for our cars, but I'll do it if I ever have to bleed mine again.

I think tires off the ground is much better for the tires. I always try to avoid "dry turning" the wheels to reduce wear.

[Schreier]

I remember reading “tires off the ground” somewhere. Must have been TIS or bentley.

The instructions for the Chase Bays power steering kit I installed on my Z3 also said to keep the front tires off the ground when going through the bleed procedure.

My thoughts are it's probably because people are cautious about putting a lot of force through the PS system when it has air pockets. If you lift the wheels off the ground, you need less force to turn the wheels left and right.

[zellamay]

The instructions for the Chase Bays power steering kit I installed on my Z3 also said to keep the front tires off the ground when going through the bleed procedure.

My thoughts are it's probably because people are cautious about putting a lot of force through the PS system when it has air pockets. If you lift the wheels off the ground, you need less force to turn the wheels left and right.

Did it say whether to have the engine on or off? The video was specific: engine off.

[Schreier]

Did it say whether to have the engine on or off? The video was specific: engine off.

Both - you go through the bleed procedure with the motor off (pump not running), then you do it again with the motor on (pump runnning).