So it turns out RA was right: the condenser is leaking. Or some fitting or connection near it, far as I can tell at this point. I put pressure on just the high side to check like Only said and sure enough, obvious hissing sound from somewhere near the pass side of the condenser.

The part I don't get is how it seemed to hold vacuum and pressure while working on it the past three days.

---AutoMerged DoublePost---

So I throw in a can of stop leak because I'm tired of working on this thing, start charging again, pressures rising up to 175 on the high side, I think great - it must be doing something. Starting to cool in the cab, excellent, right? Then after about 10 mintes or so of running/charging I hear a loud "POP, swoosh, grrrrr..." Lo and behold, there is coolant gushing down the front of the engine. Wonderful:

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_239.jpg

Have you ever seen a water pump go in such a spectacular fashion? The pulley was so cockeyed in there I cannot believe it didn't shred the belt. Better in the garage than the side of the road, I suppose.

One step forward....