[e90yyc]

Installed new Luk (OE) pump last night.

If I turn the wheel when stationary, I can hear a slight noise. Nothing terrible, but audible. I know that this is putting more stress on the pump than regular driving, but it is a new pump...

Just wondering if this is normal. It's been a while since I've owned or driven a car with hydraulic power steering—plus my old pump was making noise—so I've forgotten what to expect.

Just looking to keep an eye on it if this is something abnormal. I purchased it from RockAuto, so I'm assuming time is of the essence if there are issues. I would have bought it from FCP Euro, but it was over $100 more ($337 versus $231).

Thanks

Please see my latest post below for update

[ewicky]

I have an N54, not sure if that's the same pump.
I'm pretty sure mine is dead silent until I hit the end of the rack. Then it hisses loud thru the bypass, like every other hydraulic car.

Maybe your rack is due for replacement. Also check your tire pressure of course. But I imagine you're on top of that.

[e90yyc]

Originally Posted by ewicky

I have an N54, not sure if that's the same pump.
I'm pretty sure mine is dead silent until I hit the end of the rack. Then it hisses loud thru the bypass, like every other hydraulic car.

Maybe your rack is due for replacement. Also check your tire pressure of course. But I imagine you're on top of that.

Thanks! Tires are good, but I didn't even consider the rack.

I did not know a failing rack would cause noise similar to what a PS pump would make! I think I'll avoid replacing that unless absolutely necessary though, as it looks quite expensive, and a total PITA thanks to xDrive...

[Efthreeoh]

Are you sure all the air is purged from the system, and that fluid level is correct.

[e90yyc]

Originally Posted by Efthreeoh

Are you sure all the air is purged from the system, and that fluid level is correct.

There could still be air trapped in the system, there's no doubt about that. I've heard that it can sometimes take days for any air bubbles to work themselves out, though I have no idea whether this is true.

When I refilled the system, I did my best to work fluid into the lines by turning the wheel lock to lock a number of times with the engine off and wheels in the air. I made sure reservoir was full after doing this. I then started the car and turned the wheel, at which point the reservoir ran dry and there was a bit of pump noise for about one second before I killed the engine. After that I topped the reservoir off, turned the wheel a few more times with engine off and car in the air, and then restarted. After turning the wheel a few more times with engine on, I topped off the reservoir once again (level didn't decrease by much that time) and that was that.

I'd say I'm paranoid about having damaged the pump, but I just can't see that being the case. It was an incredibly brief moment that it ran dry, and from everything I've read, it takes a heck of a lot more than that to actually do damage. My wheels were also suspended so the pump wouldn't have been working nearly as hard as it would if I ran it dry while actually driving. My guess is air, but if the noise doesn't subside (again, very very faint, but still there), then I'll be a bit more concerned.

[Efthreeoh]

Originally Posted by e90yyc

There could still be air trapped in the system, there's no doubt about that. I've heard that it can sometimes take days for any air bubbles to work themselves out, though I have no idea whether this is true.

When I refilled the system, I did my best to work fluid into the lines by turning the wheel lock to lock a number of times with the engine off and wheels in the air. I made sure reservoir was full after doing this. I then started the car and turned the wheel, at which point the reservoir ran dry and there was a bit of pump noise for about one second before I killed the engine. After that I topped the reservoir off, turned the wheel a few more times with engine off and car in the air, and then restarted. After turning the wheel a few more times with engine on, I topped off the reservoir once again (level didn't decrease by much that time) and that was that.

I'd say I'm paranoid about having damaged the pump, but I just can't see that being the case. It was an incredibly brief moment that it ran dry, and from everything I've read, it takes a heck of a lot more than that to actually do damage. My wheels were also suspended so the pump wouldn't have been working nearly as hard as it would if I ran it dry while actually driving. My guess is air, but if the noise doesn't subside (again, very very faint, but still there), then I'll be a bit more concerned.

I've done my PS fluid twice, and the exact same method as you. The pump starves a bit but I don't think it hurts it. My pump is original. I hate the sound, which is why I do the fluid every 150,000 or so. I'd drive it for a few days, then put an ear back to it and see how it is.

[e90yyc]

Okay, so I've done a bit more digging and here's where things are at. Input greatly appreciated!

• No noises other than regular engine noise when car is started WITHOUT serpentine belt
• Alternator bearings recently replaced, but sound was present before I did that job. No noticeable change post-replacement. Ruled out alternator as source of noise.
• AC Compressor pulley bearing could be in need of replacement; HOWEVER, I have fitted the shorter belt (as suggested in AC bypass DIY) to remove the compressor from the system: noise is exactly the same. Ruled out compressor as source of noise.

Alternator pulley, idler, and deflection pulley are all near-new and spin without any unusual sound or resistance. As far as I can tell, this leaves the power steering system as the only possible culprit.

What's jamming me up here is that I just don't see how a brand new, OE Luk pump could be the issue. It just doesn't make any sense.

As ewicky suggested, perhaps it's the rack. This is starting to seem like the only logical conclusion here. I just didn't know a bad rack would make noise when just sitting there...? Everything I've read seems to indicate issues once the wheel is turned: popping, stiff steering, leaking, etc.

I'm hearing two distinct but obviously related noises:

1. a slight groaning that responds to engine speed and steering input
2. a very faint grinding sound that can be "played" when stationary by wiggling the steering wheel back and forth. It almost sounds like a quieter version of what you'd hear when turning steering to full lock and triggering PS pump bypass valve. The noise also responds to steering input. If I put my ear up to the airbag, I can hear this noise very clearly.

Does this sound like a rack that's on its way out? Not sure what else it could be given all of the above. 302,000 kms.

[lowrydr310]

Originally Posted by e90yyc

I'm hearing two distinct but obviously related noises:

1. a very faint grinding sound that can be "played" when stationary by wiggling the steering wheel back and forth. It almost sounds like a quieter version of what you'd hear when turning steering to full lock and triggering PS pump bypass valve. The noise also responds to steering input.

What you described is exactly how my power steering pump sounds. I have 230K miles on my car (370K km) and I believe it's the original pump, so maybe that sound is normal?

I have two quarts of Pentosin CHF-11S in my garage waiting to do a power steering flush, and I was kind of hoping that would quiet things down, but it sounds like you still have the noise with a new pump and new fluid.

[e90yyc]

Originally Posted by lowrydr310

What you described is exactly how my power steering pump sounds. I have 230K miles on my car (370K km) and I believe it's the original pump, so maybe that sound is normal?

I have two quarts of Pentosin CHF-11S in my garage waiting to do a power steering flush, and I was kind of hoping that would quiet things down, but it sounds like you still have the noise with a new pump and new fluid.

Hmm! This is good to know. I appreciate you sharing this.

I’m just scratching my head because this is brand friggen new OE pump with (mostly) new fluid... it just seems too unlikely that it’s the culprit, which makes me wonder if there isn’t some sort of restriction in the line or other type of flow blockage. But like hell I'm about to start replacing pressure hoses just to see...

Now I’m curious if anyone else has this same sound. It’s abundantly obvious that my noises are steering-related. I’d just like to figure out if I should replace the pump while I still can...

[e90yyc]

I've gone ahead and ordered a replacement pump. This way I'll know for certain that I didn't just have a lemon.

Any advice on other areas to explore would be appreciated. I'm game for just about anything other than dropping the steering rack.

Could it be my fluid? I changed out about a quart a year ago, and then changed another quart last week when I replaced the pump. PO had system flushed every couple years at the dealership... When I remove the cap and put a small drop of fluid on white paper, it looks very clean, but there is a very very small amount of very fine sediment.

If it's impossible for the rack to make noise when sitting still, then it has to be coming from the pump, no?

[mecheng77]

Post a video of the noise for reference

[e90yyc]

Originally Posted by mecheng77

Post a video of the noise for reference

Hope this helps!

Just to reiterate: this noise is not present when I run engine without the serpentine belt. It is also not present when I run with shorter belt and bypass AC. Alternator bearings brand new so I’m 99.9% certain this is steering-related.

[KnighTT]

I had a R53 Mini Cooper, which is all BMW parts, and had the PS pump replaced under recall. It always had a bit of a wine to it under load. I thought it had an issue.

The new one sounded exactly the same. It was much more noticeable due to the small size of the car but they do make some noise.

[nsjames]

Originally Posted by KnighTT

I had a R53 Mini Cooper, which is all BMW parts, and had the PS pump replaced under recall. It always had a bit of a wine to it under load. I thought it had an issue.

The new one sounded exactly the same. It was much more noticeable due to the small size of the car but they do make some noise.

those were electric, and pretty known for being noisy. THey released an updated part to deal with the NVH IIRC. Been a while since My brother owned his.

a rack with an internal leak could certainly make noises, just as a pump that's bypassing fluid would.
since you can clearly here it i nthe steering wheel it sounds like it's probably the rack making noise.

I'd deal with it until the rack fails, which may be never.

[e90yyc]

Originally Posted by nsjames

those were electric, and pretty known for being noisy. THey released an updated part to deal with the NVH IIRC. Been a while since My brother owned his.

a rack with an internal leak could certainly make noises, just as a pump that's bypassing fluid would.
since you can clearly here it i nthe steering wheel it sounds like it's probably the rack making noise.

I'd deal with it until the rack fails, which may be never.

Thank you. This is what I was hoping to get... some reasoning as to why it would be the rack and not the pump. I almost feel that replacing the pump again is a waste of time. Agreed?

And indeed the noise is clear through the steering wheel, at least in terms of the “grinding” sound.

Think there’s anything that could be done to quiet this down? A thorough flush?

Could always throw in some PS Stop Leak (just kidding...).

[e90yyc]

Is there any reason a failing rack would mulch my new PS pump? Fluid has always looked to be in decent shape.

It’s a bummer because I now know my old pump was probably just fine haha. The things you learn..

[nsjames]

unless there's metal in the fluid, probably not.

if the rack has fluid bypassing an o ring seal internally there's not really anything to be done. If it's not crunchy, lost it's power assist,or leaking badly, run it.

You could try a stop leak product, they are mostly just chemicals that swell rubber. But I honestly don't know the material of the seals/soft parts in the rack. if they're viton or something, those products aren't likely to work.

You'd have to do a lot of research and ask some questions before pouring the snake oil in there.


you know, the one thing I had not thought of was the reservoir.
It has a filter in it, and even though you say the PO had the fluid changed regular, maybe your fine sediment has plugged the filter and it's lightweight starving the pump suction line?

I don't know. Your deal is weird. a

[e90yyc]

Originally Posted by nsjames

unless there's metal in the fluid, probably not.

if the rack has fluid bypassing an o ring seal internally there's not really anything to be done. If it's not crunchy, lost it's power assist,or leaking badly, run it.

You could try a stop leak product, they are mostly just chemicals that swell rubber. But I honestly don't know the material of the seals/soft parts in the rack. if they're viton or something, those products aren't likely to work.

You'd have to do a lot of research and ask some questions before pouring the snake oil in there.


you know, the one thing I had not thought of was the reservoir.
It has a filter in it, and even though you say the PO had the fluid changed regular, maybe your fine sediment has plugged the filter and it's lightweight starving the pump suction line?

I don't know. Your deal is weird. a

Knowing my history it really doesn’t surprise me that I’d have weird, uncommon issues haha.

Thanks for all your help; really truly appreciated!

I’d be very hesitant to use a stop leak product unless things were really bad. Still seems to drive and steer okay. Backlash may be a bit high but it’s not too noticeable.

I replaced the reservoir last year. And prior to installing new pump—just to be sure—I removed it and cleaned it thoroughly. Sorry, I forgot to mention that in OP.

[Efthreeoh]

I listened to the video on my $19 Sony headphones

I gotta say that I think you have BMWitis over this (said only with love Brother ). Yeah it's a bit noisy, especially at full lock, which one would expect. It doesn't seem overly loud to me, based on the video, which is from your cell phone I assume (i.e. not an LA-level produced movie clip...). I know you are chasing this with a new new pump. But I think it's a bit obsessive. It's definitely the steering hydraulics since you've isolated it via the shorter belt that eliminates the AC pump and it makes sound when you move the steering wheel. But I have to ask, when you drive the car, with all the other noise that brings, especially with the HVAC blower on in normal auto mode, do you hear the same noise? I've found with BMWs that you need to let the parts break in.

For instance, when my alternator died and I replaced it with a OE BMW unit, I wrote in my notes I thought the engine idle "note" changed a bit and was more "rough" than normal. Following my own advice I ignored the urge to get BMWitis, and let the alternator break in. After a few days (for me 600 miles), the idle note improved and the alternator has been flawless since. Another example; early on the E90 was noted for squeaking steering (at the clock spring in the hub). Again, ignoring the urge to get BMWitis, I didn't let the noise concern me much and it eventually subsided. It's been 350,000 miles since the squeaking steering wheel. One more... the E90 was early on noted for a jamming steering lock (anti-theft device). My car jammed a few times and I was concerned about it. The original warranty repair for BMW was to replace the steering column, which I wasn't up for. Then later, BMW just modded the software to increase the voltage and dwell time the voltage was applied to the lock solenoid. I had that fix done under warranty, and the steering lock has not acted up since.

Now you are worried the steering rack is the culprit. Internal leaking? Okay, but is the rack acting up? Is the car now steering differently than before you replaced the steeping pump? The rack is a simple device, it pushes the hydraulic piston one way or the other, "a leaking o-ring" internal to the rack (if there really is one...) would make the hydraulic pressure inside the rack fight itself (is basically what you are saying) and I'd think you'd experience a degradation of the steering performance. I doubt a new pump would blow an o-ring in the rack just because the new pump is making better pressure than the pump it replaced(?). Really sounds like you are getting down a rabbit hole (again just said with love..). When the new new pump comes in and you install it, just let it break in. If something else in the steering system then breaks, deal with it when it does.


My 2 cents Brother

[e90yyc]

Originally Posted by Efthreeoh

I listened to the video on my $19 Sony headphones

I gotta say that I think you have BMWitis over this (said only with love Brother ). Yeah it's a bit noisy, especially at full lock, which one would expect. It doesn't seem overly loud to me, based on the video, which is from your cell phone I assume (i.e. not an LA-level produced movie clip...). I know you are chasing this with a new new pump. But I think it's a bit obsessive. It's definitely the steering hydraulics since you've isolated it via the shorter belt that eliminates the AC pump and it makes sound when you move the steering wheel. But I have to ask, when you drive the car, with all the other noise that brings, especially with the HVAC blower on in normal auto mode, do you hear the same noise? I've found with BMWs that you need to let the parts break in.

For instance, when my alternator died and I replaced it with a OE BMW unit, I wrote in my notes I thought the engine idle "note" changed a bit and was more "rough" than normal. Following my own advice I ignored the urge to get BMWitis, and let the alternator break in. After a few days (for me 600 miles), the idle note improved and the alternator has been flawless since. Another example; early on the E90 was noted for squeaking steering (at the clock spring in the hub). Again, ignoring the urge to get BMWitis, I didn't let the noise concern me much and it eventually subsided. It's been 350,000 miles since the squeaking steering wheel. One more... the E90 was early on noted for a jamming steering lock (anti-theft device). My car jammed a few times and I was concerned about it. The original warranty repair for BMW was to replace the steering column, which I wasn't up for. Then later, BMW just modded the software to increase the voltage and dwell time the voltage was applied to the lock solenoid. I had that fix done under warranty, and the steering lock has not acted up since.

Now you are worried the steering rack is the culprit. Internal leaking? Okay, but is the rack acting up? Is the car now steering differently than before you replaced the steeping pump? The rack is a simple device, it pushes the hydraulic piston one way or the other, "a leaking o-ring" internal to the rack (if there really is one...) would make the hydraulic pressure inside the rack fight itself (is basically what you are saying) and I'd think you'd experience a degradation of the steering performance. I doubt a new pump would blow an o-ring in the rack just because the new pump is making better pressure than the pump it replaced(?). Really sounds like you are getting down a rabbit hole (again just said with love..). When the new new pump comes in and you install it, just let it break in. If something else in the steering system then breaks, deal with it when it does.


My 2 cents Brother

Really appreciate the response! And I totally get where you're coming from. I go on these blitzes during the summer to fix things because our winters are f*cking freezing and the last thing I want to do is be out in the garage working on my car. While I might start by doing a couple simple jobs that actually need to be done, I can quickly get carried away chasing down issues that really aren't urgent (like this... )

After giving it some more thought, I figure there's little to be gained by swapping in another new pump. As it stands right now I'm leaning toward just leaving my "new" pump in there. I'll make my final decision on the "new new" one before the return/exchange period expires next month.

The truth is that no, it's not something that's really audible except at idle with HVAC on low or when steering at low speeds. The timeline of events was: bought car with noisy PS. Very noisy. Eventually replaced with used eBay pump with about 100k miles; changed reservoir and fluid at same time. Noise was much better. Fast forward to now, and (BMWitis be damned!) I swore it was getting worse and figured the used pump must have been making some noise all along. If I could go back and do things over, I'd probably have just left it. Hard to say whether the noise improved with the brand new pump or not.

Since the noise I'm hearing (video) has arguably been present since the moment I bought the car, I definitely don't think the new PS pump (or the used one) did anything to damage the rack. If there is an issue with the rack, it's subtle and doesn't seem to affect steering performance. Again, bought the car with high mileage so I don't have a reference point for what it was like when new. I have xDrive too, so replacing the rack is a complete and total pain in the ass as it requires dropping the subframe. I have no idea what the internals of these racks are like, but it's the only logical conclusion I can get to at this point. But to reiterate: I haven't noticed any real issues with the steering, other than the noise!

Interesting to hear about the jamming steering lock fix. I knew this was an issue, but PO had the column replaced under warranty. Typical BMW "replace it all" approach to problem solving. The other fix sounds much smarter.

I'm with you 100% in that I'm not going to touch the rack unless I actually have issues. So I guess the only question is: to replace pump again or not? Haha...

[rawdog573]

Make sure it's full. Take the cap off and turn the wheel to full lock when you hear the engine big down slightly. Do it both ways a few times. Then put your cap back on. Easiest way to get the air out if there's any in it

[mecheng77]

Noise isn't too bad. At full lock I have a similar noise, but that is hard on the pump