'04 W211 - whining - hydraulic pump?

[E55BOF]

My '04 E55K has a (fairly low-pitched) whine from the front of the engine. It is worst when stone-cold, rises and falls with engine speed, and varies slightly in pitch when I turn the steering wheel, so I'm 99% certain it is the hydraulic pump. The fluid level is correct in the reservoir, and it looks clean, though there is a possibility that it has been topped-up with Dexron III in the near past. Could this be causing the problem?

Does anyone have any ideas on a possible cause/cure?

 

[KillerHERTZ]

Its not the SBC pump making the noise?

 

[E55BOF]

No, definitely not. The sound is higher-pitched than the SBC, and continuous, and varies with engine speed and steering load.

 

[E55BOF]

Took it to Terry at Wayne Gates. It's whining OK, but not excessively; he advises monitoring it to see if it gets worse. Good enough for me...

 

[guyvert1]

Wheel Bearings ?

 

[whitenemesis]

When stationary?

 

[guyvert1]

Hahaha erm no

 

[Alps]

supercharger whine is normal

bearings go so keep an ear out for any bearing related noises from any of the pulleys

 

[E55BOF]

Definitely power steering pump. Terry at Wayne Gates advises that just keeping an eye/ear on it will suffice for the moment, and that they all whine, but it is much louder than the same pump on my '03 example with similar mileage, and it spoils the car a bit.

Three questions:

Is the reservoir level checked with the cap screwed home, or just resting in place?

Either way, the fluid level, I now realise, is too high - much too high if it is checked with the cap screwed home. Is there any chance that this could be causing the problem, or am I really clutching at straws now?

Is there a filter in the reservoir that could be causing the problem?

 

[falcoron]

i had similar and a leak on an old audi, lucas power steering leak and whine cure all, cured both leak and noise. i have used this on 4 other cars now and my boss just did on his alpha and every one has been cured. mixes with any type of fluid i just syphoned out as much as poss with a big syringe and top up with the lucus stuff turn engine on turn from stop to stop 4 times and cured! every single time.

 

[E55BOF]

Thank you for the suggestion, but that product is basically a leak stopper, and there is no leak. Also, it seems to me that it is near the edge of the Snake Oil category, and I'm leery of that sort of thing; you never know what it will do to the rest of the system further down the line.

If somebody tells me the correct position of the reservoir cap for checking the fluid level, I'll set that correctly, and replace the filter if there is one, and see if there's any change.

Thinks: ISTR a steering rack leak being fixed in the not too far distant past. The steering does not require any more effort than my '03 E55K, but is it possible that it might not have been thoroughly bled, and there might still be a little air in the system causing the whine?