Firstly, a blockage should have shown up in the gauge readings early on. It would also take a little time after the clutch engages to build enough pressure to lock up the compressor. On my car, it liked to squeal/squeak as soon as it was started up.

I know, without a doubt, that I have exactly 8oz total mineral oil in my system. I had to drain the PAG oil from the compressor before installing it. I got exactly 6oz out, flushed with mineral oil, drained, added 6oz mineral oil and 2oz in the drier.

The belt was tight to get on and I employed a flat head screwdriver to help slide it on. I am assuming The Don received the same size belt as I did. Keep in mind that when tightening the belt, you must loosen some of the bolts that hold the compressor to the bracket so it can move. If you don't do that, the bolt will break off with enough force.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge