I just replaced the a/c compressor, drier and expansion valve on my 85 300DT sedan. I used the Diesel Giant DIY for a guide (there wasn't one on this discussion), and a friend who'd done this kind of work before. I plan to have the system professionally evacuated and recharged now that the replacements are installed (see my concluding paragraph for more about how the operation was performed).

I have a few questions regarding oil and refrigerant:

1. I left the electronic cables disconnected from the compressor. Is it safe to drive it like this without any charge?

2. I put 4 oz. of oil in the compressor before mounting it as it instructed on the DIY page. When I went to mount the compressor, most of this oil spilled all over my hair (lol). Q: Do I need to ask the person who evacuates and recharges the system to add extra oil to the system/compressor?

3. I'm debating the R143a vs. R12 refrigerant. I know that the R12 is cooler, but I'm one of those hippie types that doesn't want to use the R12 for environmental reasons. Will it really make that much difference?

FYI for responses: I did flush the system with one can of flush, and evacuated it with an air gun until no liquids came out from any of the lines. I also replaced all of the o-rings using oil to lubricate them. I also used the 100 oil for the 134 oil to fill the compressor and drier thinking that I would be continuing with the R134 refrigerant (the car is already retrofitted). Lastly, I used a compressor from ********AZ that is not the factory one-I wish I'd read the posts about using the MB one prior to the install (it took around 8 hours to do all the work, and I'm not going back now!)...