Everything on the dishwasher works correctly, except the upper dish rack items do not get cleaned. It appears that the upper spray arm is not getting sufficient pressure to rotate. Both upper and lower arms spin freely.
I have taken the housing for impeller inside the washer tub apart as far as one can and have found nothing. The metal screen below the impeller is clean, as are all the parts where you can take out screws and inspect.
Only two things seem to be potential answers – The impeller blades are worn (do not really look bad) or the rubber seal for directing water to the upper arm is worn out. The rubber seal is quite flexible, but ???
Can anyone help? Or is the just an OLD dishwasher that needs to be replaced?