OK, I tried the spray with HPL PTEE, it's getting thick and sticky.
It seems to kill my PRM, but it's damm silent (at 5v).At 12v I can hear the noise of the air, and that's quite loud, but it has an "overkill" airflow
As I want to run it at 5v it just does not have enough air flow... :-(
So I decided to flush it again with WD40, and use silicone.
With silicone my RMP is back :-) but after running a few days the pitchy, whiring sound comes back again
I also tried the 7v trick, but it seems like you can not run that much amps over that trick. My psu won't start.....
Well, I guess I'm going to soke it again with HPL PTEE , and let it run for a few day's.... Maybe it will speedup again.