Peter L Timonium , MD September 18, 2016 Appliance: General Electric Dishwasher GDWT160R10SS Ge Dishwasher Gdwt160r10ss: Heavily crusted upper spray in dishwasher. How to replace Upper Spray Arm Assembly. Typical dishwasher cleaners are insufficient. While the interior gleams after each cleaning, the plastic parts accumulate a white, hard crust. And on pieces with small spray holes, this can be bad if not disastrous. So I searched for YouTube videos, a long the lines of "repair dishwasher upper spray arm," only to find that replacement was both a much better idea, easy to do and inexpensive -- a part for $4.53. I even removed the crusted arm to be sure I could replace it, and found that to be a simple process. So I clicked through to the link on the video, which took me to ApplianceParts, ordered the part, waited about two days for it to arrive, and took perhaps ten minutes to replace the part. Voila! Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes