I don't see how a faulty check valve could cause a black residue but at this point I guess anything's possible. It's easy enough to check when you remove the drain hose. Make sure the drain hose loops higher than the bottom of the sink before it connects to the drain.
Update: I have been washing all utensils by hand. The Rails in the dishwasher will get a small amount of black on them still, but it doesn’t seem as bad on the sides of dishwasher. So, more metal causes more black residue. I was reading that aluminum can cause s black residue. Wondering if maybe utensils have a small amount of aluminum in them. But that doesn’t explain why it would start now and not years ago. If I was to change the check valve, would you be able to direct me to the correct one to order? Thanks!
No. I still get the black smudgy residue on all stainless steel. Our water softener broke about 2 years ago, and we have hard city water. Of course, the problem started well after our softener broke. I’m still at a loss. Is the check valve an easy fix?
See the black elbow in the photo I posted to it above? The check valve is in that elbow, put your fingers in the elbow and see if you get black residue.
The black elbow is easy to get to, its in the very front of the dishwasher, one you remove the lower access panel you will see it. Get a pair of pliers to remove the spring clamp on it then pull that black elbow off. Have a big old towel ready, some water will come out when you do that.
I am now having the exact same issue with my whirlpool dishwasher. We have taken it apart and clean all visible areas. We run a cycle and then it's covered again on the inside. Nothing has worked to keep it from happening.
No, and my husband works on dishwashers - he uninstalled it and inspected the hoses, everything. I washed the inside 5 times, completely clean, and each time a single washing left residue all on the inside. We bought a new dishwasher - and it's not a whirlpool.
The only thing I can tell that has changed at our house is we have hard water here. Our water softener quit working a few years ago and I wonder if that could be the cause. Does your husband have any idea on that? Now that you have a new dishwasher do you have any problems? Thanks and good luck!