I have a whirlpool (aka amana) dishwasher I got from home depot a year or so ago, Model # WDF510PAYW.

A month or so ago I cleaned the upper and lower filters for the first time. They were full of soft black gunk. (Next time I will read the manual.)

Since then I am getting small pieces (1/8" to 1/4" in diameter, but thin) of black gunk on my otherwise clean dishes.

I had hoped that this would be temporary and the dishwasher would clean itself over time. That has not happened.

In addition to black pieces on the dishes, there is a black film on much of the inside of the dishwasher. (See photos.) I still get some soft black gunk in the lower filter and some grey film in the upper filter, which I clean often.

I tried running it through empty with some vinegar. That did not help.

Any ideas on what I should try now?


PS What is the round, hat shaped plastic piece in the lower right hand corner of the first photo? It has some black gunk under it but I cannot get it off to clean it.

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  • 1
    The round hat shaped plastic piece in the lower right hand corner of the first photo is the fill overflow safety stop float. It should move freely up and down about 1/4 inch. To remove it see e.g. youtube.com/watch?v=l30nQ7JXQ20. Jul 4 '16 at 21:21

It looks like mold or black mildew.

It commonly starts growing on and in the door gasket, which is somewhat porous. It collects on the filters until, as you have learned, you clean them. Then small pieces escape and stick everywhere.

Bob Villa and others recommend bleach or vinegar for controlling mold in a dishwasher. But your infestation looks too far advanced for such mild treatment.

You should use a cleaner called Affresh which was designed by front load washer manufacturers to remove mold and mildew build up.

Unfortunately Affresh and like products are not good at cleaning the mold from porous rubber parts. Try flexing the gasket away from the tub and scrubbing behind it with a stiff toothbrush.

If this doesn't work then you will probably have to replace the door gasket. The part costs around $80.


It seems this problem arose because I was trying to save power by not using the dry function and running the dishwasher at night. That meant the dishwasher sat with moist dishes in it for several hours each night. After 2 years of this, the black gunk appeared suddenly one day. I tried vinegar and Affresh tablets a few times (not at the same time) but that did not help much. I now run the sink garbage disposal before each dishwasher load (thanks for a diy suggestion) and open the dishwasher door after the dishwasher stops. The black junk no longer builds up, and the existing junk is largely gone. But there was still some black gunk on the walls and floor. So, I tried running it with bleach and that worked wonders. After that, the sides and floor were shinny clean, and only a little black gunk remained in some very hard to get to crevices. I cleaned that out with a toothbrush.

Update: It has been a good several weeks and the black gunk is completely gone. The sides and bottom are perfectly clean. Moral: do not let wet dishes sit in in dishwasher, even if the dishes are clean.

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