Maytag dishwasher leaves black spots all over insides of cups/mugs on top shelf

Do you have problems elsewhere? Have you tried draining the hot water tank to see if there are minerals built up in there? Are you using some cheap detergent?

And what's the history, how old is it? Did it work fine for years and this is a new problem? He said the spray arms are constantly blocked too, which isn't right.

These things are quirky. The ge here usually works fine, but every couple of years, suddenly dishes come out dirty. Rarely have I found a cause. Might be one opening in an arm blocked, but can't account for stuff on both levels not getting cleaned. Like the poster, I've taken out the screen, checked, cleaned it all, they still come out dirty. Then after a few more uses, suddenly back to normal again.

No, no other problems and I dont think it is a disintegrating impeller, the dishwasher is only about ten years old. It might be stuff coming off my teflon sheet. But it remains swilling around the machine cycles after I have stopped cleaning the sheet,

So I am wondering why the cycles dont simply drain the powder away during a first wash, not to mention the second wash

There doesn't seem to be water making its way through to the upper level tray

Suppose you disconnect the washer from the water supply. Connect a hose to the supply and run the water directly into the drain. No idea if it would help but it should at least eliminate one potential problem.

Can you follow the path of the plumbing inside and it looks OK? On mine there is piping from the bottom up to the top and the arm under the top basket plugs into the piping. Mine the arms come off via one bolt so you can inspect and clean, make sure the holes are really open. I've used the air compressor to blow mine out.

Wonder what would happen if you put a smartphone in a sealed plastic bag and tried to video what goes on inside when it runs? Probably would be too blurry to work.

When I got that with my original dishwasher, it turned out to be that it occasionally had a brain fart and didn’t do the wash cycle because it decided that it hadn't got enough water to be safe for heating it to the full wash temp. I only noticed why it did occasionally do that after I had retired and noticed that it finished quicker than normal with those runs that didn’t wash the dishes. I used to put it on just before I headed out to work because it was a bit noisy.

Eventually it scaled up the input solenoid badly enough so that it wouldn’t wash at all.

The current Bosch is much better at indicating that its got a water problem because it has a proper set of lights that indicates those common problems. The original dishwasher was entirely mechanical and had no way to indicate a problem or even any way to decide what the problem was. It just skipped to the end when it didn’t get enough water to heat.

I never had mine fail twice in a row, even if I did nothing.

DManzaluni snipped-for-privacy@gmail.com wrote

Do you wash filthy baking pans etc in the dishwasher ?

That’s the only black stuff I see much of on what I put in the dishwasher and not all dishwashers get all that off in the first or second wash and could be the problem if the filter or pump is the problem.

I'd try a test run with clean cups in both the top and bottom trays and see if you get the black stuff on the ones in the bottom rack. If you don’t, it’s a problem with the top spray system, maybe a blockage back in the feed to the top arm. And it may be that the black stuff is that blockage coming to bits now.

DManzaluni snipped-for-privacy@gmail.com wrote

More evidence of a blockage in the pipe going to the top spray arm.

That would show not much water coming out of the spray arm for the top rack, but I dunno how many phones will turn the light on when videoing in the dark.

Put a flashlight in another bag. Do I have to help you with everything?

Probably like looking through a windshield without the wipers going. I'd be worried about an expensive phone in that environment. It should be ok but......... Maybe a jar would be safer.

I don't think a jar can take a video though.

Now the rest of the story? What Teflon sheet? Can you see disintegration?

If it is blocking the spray arms there is not enough water to wash it away. It is also in inorganic material that does not react to the detergents very well.

I'd clean the machine well and ditch the Teflon sheet or wash it by hand. You may have to dry the inside and vacuum the particles out.

Yeah, the phone might have a hard time recording through the glass. It's on the long list of things I haven't tried. Dunno.

No, I don't think this is relevant as the problem occurs numerous cycles after I have left a teflon sheet in to wash. And I did dissemble the whole upper arm but the problem persisted under circumstances where I thought the black speckles/powder should have been cleaned off during an initial cycle.

Interestingly, whereas the black stuff is left inside cups/mugs, the stuff which blocks the upper arm holes is white or whiter than the deposits. Meaning cereal particles? Meaning the impeller isn't getting rid of these particles which remain so large that they block the arms?

Curiously, the black particles are ONLY in the cups/mugs! They don't manifest themselves at all within any other parts of the dishwasher.

I am beginning to lean towards the disastrous implication: That the pump is not pumping enough water around the machine at all and certainly isnt pumping strongly enough to push water into cavities such as cups/mugs?

The machine is 10 years old. Replacing the pump will probably be 30% to

Assuming the cups don't have black particles in them when you put them in, then when they are there at the end is proof that water is reaching the cups. Also, if you put a decently dirty cup in, does it come out clean, except for the black particles? Then I'd say that's a good indication that the problem isn't with the water flow. How many cycles have you run now without putting anything in that could account for the black stuff? Is it getting better, staying the same or getting worse?