Power steering whine

[pcn1]

The power steering on my Porsche 944 has devoloped a whining noise. This only hapens when the car if fully upto temp, never when cold and usually when reversing. Its not the belt slipping. Is it a case of new pump or could it just need a fluid change ?

Thanks

[teeev]

I'm probably stating the obvious but have you checked the fluid level?
Steve

[pcn1]

Level is at the max.

[annodomini2]

Air in the system? has it been leaking?

[GavinPearson]

Fluid may well be aerating. Take some out.

[pcn1]

The air should auto-bleed out the system as you run it ??
What will lowering the fluid level do ??

Cheers

[annodomini2]

You may have the wrong type of fluid in and as it gets hot expands more the extra pressure generated by this could be causing air in the header to be drawn into the flow.

If the fluid has been changed recently and you know its the correct type, take some out and give it a good run.

If you've just been topping up the fluid, i'd recommend changing the fluid if you are unsure if the type in the system is identical to what you are filling it with, mixing hydraulic oils is not a good idea. As it can cause unpredictable problems.

Or if it been a while since it was changed, change it anyway and make sure to flush the system and ensure the correct specification oil is used.

[pcn1]

OK. I'll try a fluid change first, its the cheapest option to a new pump. The car has a porsche history but no reference to a fluid change and I have never done it. The oil could be 15 years old !!