Dishwasher Q and A

A homeowner unloading clean dishes from their dishwasher.
  • 4 hours
  • Intermediate
  • 45
What You'll Need
Lime Away
Drain snake
Dishwasher vent cap
Scrubbing pad

Q. Over the past couple of months, my dishwasher’s cleaning performance has dropped. It had problems with leaving a white film on the dishes, and I was able to get that under control by using some recommended acid agents to clear it up; however, now the dishes no longer come out clean. The unit runs all cycles and seems to be doing the job, but grimy dishes come out. I have to rewash about 50 percent of the dishes, and the ones I don't re-wash are not really good and clean, either. We always rinse the dishes before we put them in. The unit drains fine, and I do not see any food accumulating in the drain area. The pump motor was replaced under warranty about three months ago. Any ideas what to check?

A. Sounds like you have a low water fill problem or maybe a water temperature problem. The water should be at least 120 to 130 degrees Fahrenheit to start with. Gel soaps can cause a lot of problems with scum and leaving a white residue, mostly when there is not enough water in the dishwasher. After it fills there should be water almost up to the heating element. Also, look for the water draining by itself.

Q. My dishwasher and garbage disposal both work fine. However, I frequently find that there is a lot of wastewater back from the garbage disposal that smells bad. Sometimes, there is so much dirty water it flows out onto the kitchen floor.

A. This problem might be caused by an obstruction in the drain line from the appliances or one in the main drain line. Plugged or restricted drain lines need to be snaked out using a plumber drain cleaning snake, which can be purchased or rented at rental yards.

You will likely have to remove the lines from both appliances to ensure those drain lines are cleared of any debris. Also, check the main drain line into the sewage line. Any plug or restriction will cause the drain water to back up and overflow. The dishwasher's vent cap on the sink may also be the cause of the problem, so it may be a good idea to replace that part as well if the problem continues after clearing the pipes.

Q. I have a sand-like substance in my dishwasher. My dishes dry with this grit on them, leaving them dirty. How can I stop this from happening?

A. If there is sand or sand-like sediment in the dishwasher and it did not get there from any item(s) washed prior, it arrived via the water supply. This means it came from either the water supply or from the pipes in the house, like if the pipes are corroded old steel or iron. If it came from the water supply and/or the piping system, it may also be in the washing machine and all other water-using appliances. Check the aerators on the sink faucets and inside the toilet tank to find out if this is the case, and if so, other major problems exist that will need to be addressed.

Some of that "grit" may actually be coming from your dishwashing soap as well. Try to remove the screen in the bottom of the dishwasher and clean out all the debris that you can. Run the dishwasher a couple of times without anything in it to further clean it out. Then, put some clean dishes in and run it again to see if you are still getting the grit.

One problem can be that some dishwashing soap needs very hot water to dissolve properly. If your dishwasher is a long way from your water heater, the water inside your dishwasher might not get hot enough. You will either have to change soaps to a liquid type for dishwashers, or you may be able to run the water in the kitchen sink until it gets hot and then turn on the dishwasher. This seems to work for the first cycle, but you will have to do the same thing when the next cycle begins. Also, try refraining from putting any soap in the second soap dish.

Q. I have a Kenmore Ultra Wash II that is about 10 years old. For some reason, dishes are now not coming out clean, even though it has worked great for a long time. I haven't made any changes in soap, loading dishes, etc. Any ideas on what to check? The arms seem to rotate OK when it is not running and everything "sounds" OK when it runs.

A. The filter screen beneath the lower washer arm may be restricted with debris, soap scum, hard water deposits, etc. Remove and clean it even if it looks fine. Beneath that filter may be more debris and/or some form or type of restriction that you can’t see right away.

When accessing the lower filter screen, you will have to first remove the lower rotating washer arm. You may also want to clean the water discharge holes, too, and be sure the inlet to the washer arm is also clear—same for the water feed into the arm.

Note the water level as well. The filler float may be stuck or restricted in its free moving up and down travel distance, restricting the water fill volume. Lots of other possible causes may be related to water flow, like a defective pump, hose restrictions, etc. So if these solutions do not fix your problem, there are plenty more things you can check.

Q. I have a Whirlpool dishwasher that seems to be working OK, with one problem. The heating element had a significant amount of white, hard water deposits buildup on it. After one cycle, the buildup (or the element itself, I can't really tell) is burnt and smells burnt. The dishes seem to get clean, but they retain the burnt smell until I rinse them with water from the sink. I've tried rinsing the dishwasher with 1 1/2 cups vinegar, but that didn't fix the odor or burnt residue. Is there a way to get this stuff off the element or will I need a new one?

A. It sounds like a limescale buildup. Try using Lime Away along with your nylon scrubber, but don't put Lime Away in the machine and run it. You don't want to get that stuff all over the dishwasher. Once you get the junk off, look the element over closely for a breakdown on the sheath. If you find that, replace the element altogether.