I picked up an early 90s Frigidaire labeled D&M dishwasher for "fun". Its more on the higher end of the MOL spectrum, I feel like its about one from the top when I look at comparable American machines and brochures.
A quick look underneath led me to see one very, very interesting thing. The drying fan doesn't blow, it sucks. Literally. Its designed backwards.
In Maytag or Kitchen-Aid machines the fan either blows the air across the bottom and then up, or pumps warm are in to the machine (sometimes), respectively. Either way the air may be pre heated or swept along the bottom to be heated by the heating element before being pushed out the machine. This was not the case with the D&M, the fan blows the air OUT of the dishwasher by sucking it OUT of it. The fans suction is at the bottom of the tank and it exhausts underneath the machine in the cabinet. Meaning the hot air generated by the element will just short circuit to the suction of the fan instead of using that heat to evaporate the water off the dishes. LOL.
Surely this couldnt be so? I checked parts breakdowns and it sure is. Maybe the machine heats first and then turns the fan on later to draw the hot air out of the machine? Nope, fan comes on right away with the heater.
Anyways, have a look at the pictures, this is how centrifugal fans work. But they engineered it the wrong way. Pumping hot, moist air in to a closed cabinet space.
Years ago Kenmore dishwashers were like that and yes, it does damage the cabinets. But I was just happy to have a dishwasher at all and most people who bought low priced Kenmores probably felt the same way. Even today I feel that it is a good idea to paint the space for the dishwasher with a water-resistant paint, extend vinyl flooring into the space, and provide even just a hole on the bottom to drain any leaks that will inevitably happen over the years.