SteveKapono

My 996 just started making a faint but noticeable low pitch grinding noise when turning the wheel. The wheel is also ever so slightly harder to turn.
I checked the power steering fluid and it seems to be high (both when hot and cold), however I haven't added any fluid and when I last checked it about 7 months ago the level was perfect. How is that possible?
​​​​​​​Any ideas about what's going on?

dporto

"Any ideas about what's going on?"

Someone is burglarizing your car and adding power steering fluid over night? Just a guess...

SteveKapono

That was my first guess as well!
I had to think long and hard if I've pissed my neighbors off lately. HAHAHAHAHA

ditto

Does it make the noise when turning a bit off of center, or only when the wheels are turned sharply?

Test this with the car stationary.

SteveKapono

It's not a constant noise like the pump would make when turned off center and held there. This is more of a noise whenever you are moving the wheel one way or the other, but only when you the wheel is turning. Like how you would hear the tires on pavement when turning the wheel when stationary.

ditto

Sounds like the pinion gear. Has the PS fluid ever been in need of top offs?

Ahsai

I have a theory, which happened to my Acura MDX. The o-ring on the steering pump intake port was hardened and leaking air. So instead of pumping fluid, the pump was sucking in air and pump it through the system. That caused a very bad noise and an elevated fluid level (displaced by the air).

If that's the case, it would be part #15 here http://www.autoatlanta.com/porsche-p...section=403-03

However, I've never heard of this happening in the 996 world so I'm not confident about this theory. What happens if you remove the steering reservoir cap and turn the wheel a little while the engine is idling? If there's air, I would expect the return fluid will also be full or air bubbles.

DBJoe996

I would do this: block the rear wheels, slightly get the front wheels off the ground with some stands, start the car and turn the steering wheel lock to lock. Check the power steering fluid for signs of any air bubbles being returned. Try to locate the sound of the grinding noise. To check under the power steering rack, use a mobile phone on a selfie stick and put it underneath the car. Have a buddy help you turn the rack from side to side, lock to lock, and see if you can determine where the grinding noise is coming from.
Possible problems are:
1) power steering pump not working correctly, maybe internal seal blown
2) air in the system caused by a bad seal as Ahsai has suggested
3) power steering rack is broken inside..the rack and pinion are grinding and not engaging correctly, like maybe the pinion bearing is bad
The rack is power assisted, meaning it uses pressure from the power steering pump to "assist" the rack and pinion movement side to side. It basically works like a hydraulic ram assist while the rack and pinion are physically engaged to each other. You can totally lose power assist and the steering will still work, albeit with much greater effort.
It is also my understanding the power steering gear cannot be rebuilt, only replaced. See here http://www.autoatlanta.com/porsche-p...section=403-00
My two cents worth of advice.....

Oh..BTW...where is the faint grinding noise coming from? Underneath the front of the car? Or is it the steering wheel itself? Does it come from inside the cabin?

Ahsai

^That's a great plan, Joe. BTW, if it's indeed air in the fluid, I would also expect the steering pump to make some noise so a mechanic's stethoscope on the pump will also be useful.

DBJoe996

Also, one more thought, could be a strut bearing has seized and it grinds while you are turning creating additional effort to turn the wheel. See #11 here: http://www.autoatlanta.com/porsche-p...section=402-01

SteveKapono

So I took it to my porsche mechanic (awesome guy by the way, I always love going to his shop and seeing what he's working on) and he said it was the strut mount/bushing. He sprayed some lube up in there and it stopped immediately. He said not to worry about it too much and to change it out when I do more suspension work.
As far as the over full fluid, he didn't really seem concerned, he said that it will release any excess if there really is any.
Doesn't explain much, but a little grease helped. I trust the guy, he's kept both of my Pcars running better than any car I've ever owned and always knows his stuff. So I'll do what he says and not worry. A free and simple fix rarely comes around.

5CHN3LL

He's right, the power steering reservoir is vented. Are you saying the fluid is higher now than it was previously, or was it your expectation that the fluid level would be lower now than before?

Ahsai

Joe nailed this one!