Wasn’t sure how to reintroduce oil into the system. So, gotta come back off with the R4 compressor and place half of the 11oz of oil directly into the compressor. Half of the remainder will go in at the rear evaporator the other half at the front evaporator.
Good stuff here. You've put a lot into this. I hope it serves you well for years.
I have a few comments.
About the oil...
I would put 4oz in the compressor.
I would put 4oz or more in the accumulator, so it's immediately upstream of the compressor upon initial turn on (just
wetting the desiccant bag takes a fair amount of oil). As you charge it and refrigerant begins to carry oil away from the compressor, oil will be replaced once the refrigerant starts returning from the front system through the accumulator.
I might then put the rest directly in the rear suction pipe (if accessible) for the same effect as refrigerant starts moving through the
rear system. Otherwise, I would put it in the accumulator.
Above... these aren't "hard" numbers, it's just my way of putting the oil in places where it can get to the compressor upon initial turn-on (which is likely a low-refrigerant condition, so little refrigerant / oil is flowing and the oil in the compressor is providing all lubrication)... then as refrigerant starts moving through the system (as you're charging it) it carries oil in from the accumulator to replace that carried out from the compressor.
After reinstalling all lines, I realized that I had moisture in the air compressor that I was blowing the flushed lines out with. Drained air compressor. So, going to break it back apart and blow the entire system out one last time.
That's good practice to keep the moisture out. For the moisture that's already there, I might simply put the vacuum pump on it and evacuate the system for 6hrs or more... there's nothing to lose with a long vacuum, as long as the system is tight and you're not sucking air / humidity into the system through a leak, elsewhere.
When desperate, I've used the gas from a 30# R134a tank to blow things out. It comes out dry! Nitrogen (have you a welder around?) would be fine too. Acetylene... not so good. Oxygen would be asking for trouble too.
In your pictures I saw open lines. Plug / cover them, somehow, to keep airborne dust / crap from finding its way into the system... unless your shop is like a paint booth. You don't need to be fancy (e.g., with proper fitting plugs, tho that's nice), just
something. I've used Saran Wrap and blue tape, or Zip-Lok bags across the fitting and then tightly taped-down around the pipes. I've watched experienced people pay no mind to such things, but I think otherwise. You'll not find one AC service manual that doesn't address system cleanliness, the reasons for it, and how to maintain it.
That transmission cooler on the driver's side, it looks to be held to the condenser with those plastic tie-wrap-like thingies that basically apply the weight of the cooler upon the core tubes of the condenser (or the condenser's fins, which in turn bear on the core tubes). That just sounds like a bad idea. The condenser has other things it needs to do, not bear the weight of an adjacent cooler that's loaded with oil. I don't know what to tell you, other than to do it differently... if that means removing the cooler or finding another way to mount it.
Good luck, keep us posted!
