Miele G7166 - Is this Cavitation?

[michaelz08]

This has been bothering me for a bit, but has become more on my mind as I'm using the pots and pans cycle more often now. The sound I'm referring to is a loud 'shhhhhh' that occurs at regular intervals. It sounds more subtle in the recording but to really manages to be not only very audible in person, but pretty annoying. The Pots and Pans cycle is loud enough as is, and this is making me not want to use the cycle altogether.

I can hear the arm's spinning slow as the sound occurs, and it occurs primarily when the bottom arm is in operation. It only occurs on the higher-pressure wash cycles such as Pots and Pans, QuickIntense, and SaniWash. It never does this on lower-pressure cycles such as Normal, even with ExtraClean enabled.

I tried adding water, and did perhaps 12 ounces (but not more out of concern for overfilling it, the base is very shallow), and it seemed to perhaps make a slight difference... But I could not tell definitively.

Audio attached, recorded with the phone near the bottom of the unit. Thoughts are appreciated.

Extra info: Cascade powder detergent inside the auto-dos cartridge, so it's determining how much detergent to use. I don't recall seeing excessive suds when I opened the door to add water.

 

[vacerator]

Either not enough water in the tub, or a loose item blocking a spray arm intermittently.

 

[michaelz08]

Either not enough water in the tub, or a loose item blocking a spray arm intermittently.

I can confirm no items blocking the arm, it occurs reliably on all high pressure cycles.

How could there be not enough water? It meters it's own filling and I leveled it myself.

 

[Marky_Mark]

This sound is most likely to happen when the pump is circulating at its highest rate, which is when it's operating the lower wash arm on cycles such as pots & pans and QuickIntenseWash.

My first thought is that it's due to suds. I've often heard this (much worse) when using Cascade Platinum pacs in various dishwashers including Miele. But I've never heard it when using Cascade powder though. It could also be due to a slight lack of water.

Next time it does this, if it happens during the main wash, open the door and add a quarter cup of vegetable oil and then let it continue spraying for a few minutes and see if it goes away once the oil has mixed in, which would kill any suds. Even though you didn't see suds, the pump could still be cavitating.

Also, try adding a litre of water and see if that stops it. Adding that much water won't overfill it.

At what point in the cycle does this tend to happen?

Mark

 

[neptuneguy27]

Definitely cavitation. My Miele 7106 does this not only in the higher pressure cycles but also when I've really packed it full. However, in the latter instance the dishwasher will top off the water level until it is running at a constant pressure. In my experience Cascade pacs are the worst offenders for suds and cause that noise in any cycle. I've not tried Cascade powder yet in the Miele, but never had a sudsing problem when Finish powder was available nor with Walmarts Great Value powder, which I am currently using.

But I digress, my machine does this same thing in the Pots & Pans, QuickIntense, & Sani Wash cycles or when I have the Intensive Lower basket option selected in the Normal cycle. But it only seems to be an issue during the pre-rinse and first part of the main wash; after that it seems to settle down a bit. Or I have become deaf to it and just don't notice the noise as much.

Chris

 

[Marky_Mark]

The sudsing cavitation often goes away once the water has reached a higher temperature -- it's much worse at lower temps. If a good amount of food soil is present, especially fatty/greasy residues, that will stop it from happening.

Despite the sudsing and cavitation, I've found Platinum pacs to be one of the best detergents. But the noise is irritating!