Some notes from my son's experience with his car that I was hoping might lead to some exchange of info:

- AC system has been completely empty since I bought it. I tried to put some refrigerant in it, but it leaked out instantly.
- Unplugged the clutch so it wouldn’t run without anything in it (although some initial miles after purchase, on a car that had sat for a couple years prior to our getting it, were done with it still connected; so it may have run dry for a bit both prior to and after purchase).
- Going to replace all the O-rings but I don’t know how to test the AC compressor to see if it works/refill it’s oil because I’m pretty sure the compressor is empty of oil.
- Considering changing to the more common refrigerant so is there anything more to the conversion than just changing the O-rings?

On the more major side of consideration, how difficult is it to replace the compressor if that is suspect?

 

Oldest TSB that I have in .pdf (not paper Bulletins) is 1997 for the Harrison Compressor used in 6 cylinder sedans and V12.
Probably more info but all the really old ones are still paper TSBs.

 

First thing, find the leak. I recommend nitrogen but some people use compressed air. If refrigerantcame out instantly it sounds like it’s a pretty big leak so you should be able to find it fairly quick. Sometimes you can hear it or use water with dish soap as a leak detector. You’ll see pretty big bubbles if you have a pretty big leak.

 

There are low and hi pressure switches to stop the compressor from running with a low charge, most of the oil is probably still there. Need to drain the compressor and measure the amount of oil that came out to get a baseline.

 

I’m not sure about a 1987 SIII, but my 1985 definitely didn’t have low or high-pressure cut-offs. It only had a thermal fuse. I added a fitting before the filter drier so I could install an A/C trinary switch, which solved a lot of potential issues.

 

The Harrison A6 back plate with the superheat switch can be swapped out for a later one with the pressure switch.