Couple days of screwing around with the AC and it seems to be working great right now. But we shall see.
Looked everywhere I could spy and found no more leak sign in the exposed plumbing. Found some refs that a Sub with rear AC takes 3# of R134a, that's 48oz.
System was very low pressure and barely working before I put in the 12oz can of esters, dye and 10.5oz of R134. Obviously some of that leaked out. found sign on the low pressure hose connecting the receiver/drier to the compressor and some spatter on the undercarriage and some that was my fumbling the charging of the dye. Hose -
And this is where I failed to take proper advantage. I breached the system to replace the hose. I didn't vac it down, leak check it before charging, nor seize the opportunity to put a new drier, orifice tube on - cheap but essential parts and no better time to swap them out than while the system is breached.
After re-assembly I put a 22oz can of r134a+ester/seal conditioner in the system. Blew cool. Worried about the 'air' in the loop. Then found the 'takes 48oz'. Drove it for a few trips and some driveway time at elevated idle and performance (or lack of it) stayed the same.
So today I put another 12oz can in today and drove it around some. Much better.
Pulled the dash ductwork cover off and opened the cabin air filter access cover off - another missed opportunity, filter set is $6-13 on rockauto, $27 at Autozone. I changed them last when I first bought the vehicle, 5yrs+ ago. They were pretty dirty. I shop-vacced what I could.
With the filters out I could jam my UV penlight up in the slot and view the upwind face of the evaporator (heat exchanger) and I found a little dye. The stuff is persistent. Might be my shot, might be an earlier one, vehicle was 13yrs old with 116k mi when I bought it.
And judging from the shape of the surrounding duct and its downslope to the firewall I think I figured out where the condensate drain penetration was. but it's obscured by a heatshield / plastic cover. But I found dye sign there, too. But not much and none has hit my driveway. So a small seep. Optimistically, the leak sealer might have done its job before much passed.
So I'm right about $200 into this (so far). $100 for the shipped AC Delco hose. $50 for R134a etc. About $50 for a nice manifold gauge set that is a very good diagnostic tool. My system functions, all the electrical, solenoid, compressor clutch etc are good. I MIGHT still have an evaporator leak.
If the system loses its cool again, I presume the evaporator is leaking and I hack a hole in the duckwork to replace it. While doing so I replace the drier and orifice too. And upon reassembly I properly vac it down and verify no leaks before a re-fill. And I'll STILL be $250-1500 ahead of what my local AC shops want.