I have a new LG washing machine installed and the cold water valve from the wall makes a loud whinning/whistling noise when the cold water runs into the washing machine. What is causing this noise and how can I stop it?

Make sure that valve is fully open. It sounds as if you have a washer in the valve that is vibrating. Most valves can be rebuilt but first tell us if its 100% open.

Yes, the valve is completely open. Its only the cold water valve that makes this noise. Its not a vibrating sound, its more like a loud whistling noise. I flushed the water to make sure there was no air in the line but that wasn't it.

Shut the water off to the house and unscrew the bonnet packing nut. Pull the stem and washer assembly out. Replace the washer. Before you reassemble the valve turn the water b ack on for a few seconds to flush out the supply. Reassemble and test. Better now? Good luck, Tom