928man

My power steering is making a whining noise, the fluid was low so I topped it off, still making the noise, any ideas, unit not leaking, 86.5 auto.

Tails

Bill,

Is is a whining noise of more like a groaning noise?

It may have air in the system, so lift the front and with the engine running turn the steering hard left and then hard right a few time and see if the noise deminishes as the air is expelled.
Tails 1990 928S4 Auto

76FJ55

as bill says, could still be air in the system that hasn't worked its way out yet. another possibility is the integral filter in the reservoir could be getting plugged and restricting fluid flow. if that's the case you're due for a new reservoir.
One question though if there's no leaks why was it low on fluid?

928man

I have the car one year & never checked the fluid level in the reservoir, maybe I do need a new reservoir, thanks Bill & Simon., I 'll have to double check for leaks again.

Bilal928S4

Sometimes it also helps to flush the old fluid and put fresh one in. Simeofmy other cars have benefitted with that procedure.