90Q water pump whine - tbelt is not overtight

[Radek]

Happy New Year to all Audifans and Quattroholics!

After a long rest in the garage, my son's 1988 90Q is finally on the road.  Among other things, the T-belt was changed, together with water pump and the relay roller.  The pump is a brand new Graaf.

When the car was first started after the RR, the pump was making a high-pitched noise, not too loud but quite pronounced.  I went back, loosened the belt a bit so it can easily be twisted 90 deg. with two fingers, but the whine is not going away.  It is only there at idle, when the RPMs increase, it goes away.  I checked with a stethoscope and it's the water pump, rather than the power steering pump right above that is making the noise, unfortunately.

Is there a chance that the pump will settle down, or should I replace it right away?  I'm afraid of it seizing, with all the consequences.
Thanks.

Radek.