Your dishwasher is far from a silent appliance, although modern advancements have made many of them very quiet. The sloshing of water inside the machine as the dishes get scoured clean is a normal part of dishwashing, and you may have to put up with some of that depending on your specific model. But if your dishwasher is truly making a loud and unusual noise, it may indicate a problem that needs attention.
Water Inlet Valve
The water inlet valve is the valve where the fresh water enters the machine from the supply lines to wash your dishes. This valve will fail eventually as it wears out from opening and closing repeatedly. Sometimes the valve fails slowly and doesn’t stop working completely all at once. When this happens, the valve may open too quickly, opening and closing inconsistently and causing symptoms similar to water hammer. The pipes leading to the machine may shake and rattle violently and can make a very loud noise. You’ll have to replace the inlet to stop this problem.
A spin seal protects the bearings inside a dishwasher motor. When this seal gets worn out, water can get inside to the bearings of the motor and wash away the lubrication, which can cause leaks underneath the appliance and can make the bearings noisy when the dishwasher runs. The seal can be replaced and the bearings can be lubricated to stop the noise. A more serious problem is a rattling sound from underneath the dishwasher caused by the disc mounted to the top of the motor breaking. This problem requires motor replacement.
Debris in Pump
All types of foreign objects end up in the dishwasher inadvertently. Bits of hard food like seeds or fruit pits, glass from broken dishes and other debris may clog the dishwasher pump. The pump may make grinding noises as the impeller spins and hits on the objects. You can easily remove the lower rack and spray arms to access the debris and clear it out to fix the problem.
Spray Arm Obstruction
The spray arms in a dishwasher spin around at high speeds, spraying water from tiny holes onto the soiled dishes. This whipping water is the key element that cleans the dishes throughout the cycle. When dishes or other items in the dishwasher get in the path of the spinning arms, they may cause the arms to repeatedly hit them as they spin, assuming they aren’t in a position that prevents movement altogether. This repeated tapping on the edge of a plate or stem of a glass could be a significant unusual noise.
During the drying cycle, your dishwasher uses a heater fan to dry and warm the dishes. When the bearings in this fan rust or wear out, they may begin squealing or scraping together, making for a very noisy drying cycle. You’ll have to replace the fan motor to stop the noise.
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