My ice maker works if you poor a cup of water in. The water valve and line to the ice maker feed (small black plastic tube on back) were replaced. The water is freezing in the black feed tube. I have had the recommendation to defrost and cover the tube as best I can with plumbers putty. The label on plumbers putty says "Do Not Use With Plastic." Suggestions? Clay or some type of sylicone product. Basically, the black tube must be buffered from freezing.