It was kind of hard to look at the heat exchange fins due to the way the mechanism was mounted and the location of the access panel, but they seemed perfectly clean. Shiny metal and nothing left on my fingers when I touched it.

Just to be certain, the condenser is the big fan unit outside, right? That may well need to be cleaned. It's worth looking at, but I'm not going back outside in the heat today if I can help it.

Like I said, the cold pipe was about as cold as the outside of a glass of iced tea. I would have hoped that it would be cold enough to be unable to hold onto it for very long, but I'm pretty sure that I could have held it indefinitely.

As I understand it, the AC cycle goes like this:

1. Compress refrigerant, which generates heat
2. Dissipate as much heat as possible in compressor unit
3. Pipe refrigerant to evaporator
4. Allow refrigerant to expand, absorbing heat
5. Pipe expanded refrigerant back to compressor
6. Start over

Does that sound right?

My thought at this point is that it is not able to dissipate enough of the compressed refrigerant's heat at the compressor. Does that sound reasonable? (It could still be undercharged, but I'm going to save that as my last resort.) If so, the problem seems likely to be that the compressor isn't able to move enough air over the hot tube, which could be several things, but dirty coils seems likely. I'll check that when the sun goes down.