A friend of mine gave me a dishwasher he was throwing away. It looked great and it was relatively new, but it wasn't cleaning well. He decided to punt and buy a new one instead of fixing it.
I figured I needed a dishwasher for an apartment I manage, so I took it. Now it is installed, even before I attempted to fix it. Despite its looks, I still know that it is still problematic. Now I want to figure out what's wrong. I guess it is easier for me to figure out its issues when it is hooked up.
Step 1: In-situ inspection
It looks very dirty. It has been sitting around for about a year and is covered with construction debris and etc. A little cleaning will hopefully make it look better. Fortunately, there are no dents!
There is one weird thing: the top dishwasher rack is somehow binding to the back of the dishwasher, where the water feed connects to the central arm.
Step 2: Diagnosing the rack binding issue.
I remove the upper rack, and then it is clear: one of the rear wheels was not in its track, preventing the upper rack's water supply tube from correctly engaging with the water feed tube mounted to the back of the washer. Instead of these tubes mating, their surfaces overlap and bind. My speculation is that this is the root of all bad things: This mis-alignment results in no water flowing to the central arm. Instead, a single heavy stream of water flows out the rear feed tube. This, in turn, greatly reduces the water pressure at the other arms. In turn, nothing gets washed properly.
Putting the top rack back on the track didn't fix the problem because the plastic mating part between the feed tube and the upper rack tube was distorted by months of mis-mating.
Step 3: Addressing the distorted rack feed tube
There are two "pins" used to align the upper rack tube with the rear water feed tube, and one of the pins is very bent. I imagined buying a new part (about $30), but instead I decided that it wouldn't hurt to try to UN-distort it. I used my heat gun at 220°C to gently reshape the distorted part. It isn't 100% perfect, but it does look very close. Now the rack slides into position properly and the water feed seems to mate well with the rack arm.
Step 4: Cleaning, inside and out.
After a couple of test runs, I'll load it up with some dishwasher
cleaning agent, just to help dislodge any debris and scum that might be
stuck in the water passageways.
Now that I think it works, I'm going to clean the outside of the washer with some stainless steel polish. It is pretty yukky looking but I think we'll get it looking great.
Conclusion
Other than the cleaning and test runs, the total time to repair this formerly broken dishwasher was 20 minutes: 5 minutes for diagnosis, and 15 minutes to correct the distorted part. I used a precision heat gun to correct the bad part. No parts were needed. Alternatively, I could have purchased a replacement feed tube for about $30.
But this is a nice dishwasher, and it was free for me. I would have spent, at the bare minimum, $700 for a dishwasher. I can't imagine how many poor dishwashers find their way to the junkyard when the problem is something as minor as this.