Power steering whine!!!

[ls400lpg]

I have just rebuilt the power steering leak hoping that it would cure the groan. When at stationary you turn the wheel slightly the RPM would rev up and down. There is no power steering leak now. I have topped up the fluid.

 

Any suggestions please.

[ambermarine]

The rev change is normal and is actuated by the valve on the pump which acts on the vacuum created in the plenum on the engine .

The purpose is to stop strain being put on the pump when the car is stationary and the steering wheel is turned.

[ls400lpg]

Not on mine. Mine moves 200rpm up and down and really groaning once you turn wheel. 

I am going to try cleaning the reservoir screen and do a flush. Keep you updated.