My dishwasher has developed a loud clunking sound in sync with the rotary arm. It still does it when the dishwasher is completely empty, no dishes, no basket, no filters. I cannot see what it is banging against. I have removed the arm, flushed it out and replaced it back, it still clunks. Anyone experienced this before?

Alan G, May 2013

It turns out that the reason for the spray arm catching is limescale build-up, even though I don't live in a hard water area. The build-up was uneven, causing the arm to spin unevenly. I ran a wash cycle with a small bottle of white vinegar, which removed the limescale, and the arm now spins evenly without any banging. Now all I have to remember is to add some white vinegar from time to time. Malt vinegar or other non-white vinegars will stain.

Alan G, May 2013

Yes I have done that, but cannot see where it is catching, I have manually turned the arm and it does not hit anything, and there are no signs of wear anywhere.

Alan G, May 2013

remove the nut from the centre of the spray arm might be clockwise thread to remove and then test.if noise gone it is the spray arm catching

CK, May 2013