Hello Ford Community!

I have problems with my PAS system in my MK6 Fiesta ST. 

Yesterday I replaced the power steering pump (not the first time), relocated the reservoir, flushed the system with new fluid ( cherry red ATF ) and bled the system.

Now the pump still makes the infamous whining noise. The noise is always there (no matter if the engine is cold or warm) and gets higher and louder with the rpm.

 

All parts are new, the power steering works perfectly fine, there are no leaks and the fluid shows no signs of trapped air, so none of the usual suspects seem to be the problem here.

 

Does anyone have an idea what else might cause the noise? I'm thankful for any help!

 

Have you held the steering at full lock, on each lock?

Yes, after everything was installed I first turned the steering wheel from lock to lock several times (with the wheels in the air) to get rid of most of the air. Then I started the engine and repeated this until no more air came out while always checking the fluid level in the reservoir.

If there is a filter in the reservoir make sure it’s clean. Not sure about Fords but some makes have an attenuator built in to the pressure pipe from the pump, these can cause be noisy when failing or using cheap aftermarket ones.

Thanks for your reply!! The reservoir is brand new so the filter ist clean.

I didn't know about any attenuators  though, I have to check on that.

I can add something: 

I just visited the nearest Ford dealership and asked, if someone might have 5 minutes to listen to my problem. Kindly, they sent me a mechanic who seemed to know his answer before even saying hello. Since he was clearly in a hurry I told him about my problem and everything that has been done in a nutshell. His answer: They'd have to change the whole steering system (rack, pump, hoses, pipes) because this would be the only way to get all the abrasion from the first pump out of the system. Although he didn't let me start the engine to listen to the noise and didn't even take a look at the fluid, he knew that this must be the problem.

To my question, If in this case the noise shouldn't be gone for at least a little while after flushing the system with new fluid, which it didn't, he said "in theory yes, but that doesn't mean anything."

Although his answer might be plausible, I am not sure what to think about that. What do you think? 

Thinking ‘outside the box’ , is the FEAD belt running in line. I had an escort Si  in the mid1990s and the polyV belt was one groove out on the crank pulley. It was more of a scream than a whine though