My dishwasher does not appear to fill fully. How high should the water level in the tank be? Once the fill cycle is complete the pump makes noise and the water pressure through the spray arms is very weak. The water comes out but the arms do not circulate. The pump is noisy. Is this a pump and/or fill issue? Also, what is the life-cycle of these machines? I don't mind replacing parts but I am concerned with spending $200 or more on an 8-year old machine if other parts are due to start failing. Thanks.