This issue started 3 weeks ago. When you start the washing machine and it starts to fill with water the hot water line to the washing machine vibrates. If I turn on either the cold water faucet or hot water faucet in the small sink next to the washing machine the vibration stops. The home is 8 years old. I have a water regulator on the main water input line to the house set at 50 psi. It is working and set to 50 psi (I just checked it). The house has clear plastic type water lines. The washing machine is a Whirlpool and it is 9 years old. Nothing has changed to the home water supply or to any faucets or appliances. I removed the cold and hot flexable hoses at the rear of the washing maching to ensure that the metal strainers were clean (they were) and I opened the valves on the wall to see if the water ran normally with no air bubbles or vibration. The water ran fine with no vibration or bubbles.
What is causing the hot water line to vibrate at the washing machine? That is the only place there is a vibration. A friend of mine told me that he had the same issue just before his water heater failed. If that is true, why would a failing water heater cause only the water line to the washing machine to vibrate? I would like to hear any information on how to isolate the problem or repair the problem.