My dishwasher is 10 years old. It is only used intermittently, but I do try to run it at least once a week. There is an intermittent sewer-like odor, that seems to come and go. It was really bad this time, totally smelling up the house. I can run the washer with baking soda, bleach or white vinegar, and the smell will go away for about 8 hours, then it's back. It will then go away, not to return for several months. The drain hose is looped to the top of the cabinet, there is no disposal. There is a open-ended PVC pipe about 18 inches high in between the trap and where the pipe exits the house. Does that serve as the air gap I have read about on these pages? I have taken off the sprayer arm and the filter underneath that and there was no standing water, no debris, nothing I could find to account for the smell. The door also appears to be clean. Anywhere else I should look for food debris? Any thoughts on this would be appreciated.
Here are a few things worth trying:
I reckon a hot wash would give you a few hours of respite from the smell, and nothing you've tried cleaning it with would do much against congealed grease. A dishwasher cleaning product or even just a full dose of detergent with it empty would be better.
After this, try to figure out where the smell comes from first, to narrow down the problem.
Damage to the drain hose or sump can cause a (slow) leak, and that can smell. In our case a mouse that the cat brought in chewed through the drain hose, and the first clue we had was the smell because the volume of water each time was too small to get right out. Replacing the drain hose is a bit tedious but not expensive or hard. Any leaking water could end up inside the unit so check there as well.
If there's an open pipe above a trap you may need to clean the trap (caustic soda, though the dishwasher cleaner might take care of this). If the trap is full of grease it can cause the outlet pipe to overflow.