We have a 20-year old Bosch S510. It\\\'s been fine and still washes well. Recently it started leaking from the little white box on the right side viewed from the front, only when filling at various stages during the cycle. This seems to be some overflow device, so presumably there is some restriction downstream of this. On the advice of a friend I checked the bottom of the door and this had a thick layer of gunk. I removed this as I gather it blocks a couple of holes in the bottom of the door. however, no improvement. Any other ideas?