Not much to it. I can provide model and all that stuff but don't think it is pertinent. Dishwasher squeals/whistles high-pitched right when it is intaking water – super super loud. So depending on the cycle we choose this can happen 2-4 times while it is running and each time while water is coming in.
This can be repeated and happens every time. Been months and not sure the issue has gotten worse but it definitely isn't getting better. What should I check first?
Best Answer
I don't mean this as a complete answer but what I would do to start. I'm assuming you've done the obvious like checking the supply line and shutoff valve for obstructions from calcification, etc. The problem is almost certainly in the water supply system. If the external supply line is good to go then you need to go under the hood. Usually that type of sound is caused by bad bearings in a pump or other reciprocating device. It could also be caused by scale build-up in a high water pressure area which I'm sure you've considered. Anytime too much water is being forced through too tight of a bottleneck it's going to howl.
Diagnosis
I would run the dishwasher through a short cycle with the front bottom panel removed. You can sometimes determine where a sound is coming from by placing a long wooden dowel on different components and your ear against the dowel. You can also use a stethoscope but the sound might be too loud for that. If you can't identify the source you may have to slide the dw out and try the same process from the back. The process with the dowel works best when it's not in an enclosed area where sound reverberates.
Most dishwashers are fairly simple to slide out of their enclosure by removing a couple of screws. I would slide it out as far as possible onto a piece of plywood to protect the floor being careful not to kink any of the wires or hoses. The further you can get it out while still connected the better.
I would then stabilize it so it's level and relatively secure. Check all of your connections: power cord, water supply line and drain line making sure they're not compromised in any way.
Run the dishwasher through a simple fill and rinse listening carefully and observing, particularly around the fill inlet area. It is usually much easier to determine what is causing a particular sound in this way. It will help you to zero in on one or two possible problem areas. With dishwashers most of the components are under the chassis so they're difficult to access. I would once again use either an inexpensive stethoscope or a long wooden dowel to focus in on suspect areas. A wooden dowel can be butted up to a device and by placing your ear on the other end you can get a good idea if it is the one doing the howling.
You might get lucky and immediately identify the problem or you may have to do a little trial and error by replacing suspect valves, impellers, etc. Obviously start with the simple, inexpensive solutions first. You might have to end up calling in the "Maytag Repairman" but I doubt even he could give you a definitive answer without running through a similar process. Good luck
Edit
Admittedly, it is hard to get access. Some components like the water inlet are toward the front but you may need to reach some through the back. In doing this you may have to move the drain line to the sink or use an extension. Once you've identified a possible problem area disconnect power, water and drains, and turn the dw on its side which will give you better access to replace parts. There is no easy way to troubleshoot this.