First of all, I know nothing about AC. '87 760 turbo.
I'm taking my 760 in this Monday for a new compressor and clutch..

My clutch failed (slipping and burning). Should I replace entire unit; the compressor and the clutch? with 150K is the compressor near the end of it's life?

Now for The Big Question:
I had the AC charged two months ago. It sounded noisier than usual when I picked it up. PRior History: Last November, I had a new heater core installed *different mechanic*. The AC was evacuated when the heater core was replaced.

Is it likely that the second mech 'topped off' the system -without pulling a vacuum and adding new oil- leaving me with very little or no oil in the system?

When an AC system is evacuated, does it suck out all of the freon and all or most of the oil? Should I question my mechanic about his responsibility, assuming he didn't check to see if there was sufficient oil in the compressor? Would that cause the clutch to fail? Should AC system be evac w/every service?

Will I be disappointed with 134 conversion- I've heard complaints that it's not nearly as cold as freon. I don't mind paying more (lot's more) for freon - if I only need to 'top it off' every two or three years. Do I need a new accum/dryer? what else should I replace?

Finally, are all 760's turbos?

-- thanks, this list is great! --