Air Conditioning restoration

This story is from Fiero GT 1986, but it generally applies to all GM-vehicles from 1980's.

I want to gather all relevant information for A/C conversion or overhaul. Use it as your own risk and think how this applies to your situation.

System overview

System works by...

AC system overview

Compressor and pressure switches

Great story about comporessors and pressure switches can be found from http://fierosparks.com/links/1.html
Note however, that if you are going to spend over 500 eur to A/C overhaul, why not spend extra 200 eur to make sure it works for next 10 years? I highly recommend HR6, since it gives you an option to use R134a refrigerant.

DA6 end DA6 HR6 sticker HR6 end

Hoses and tubes

Only place I know to get A/C hoses are http://fierostore.com/. However, if your tubes are okay, you may ask local A/C shop only to change hoses.

Make sure there's nothing cousing tubes and hoses to damage. I had transimission shift cable touching aluminum tube and it caused decompression of system.

Hole in the AC tube

Evaporator

Short story: Check your evaporator before A/C overhaul!
Evaporator is very difficult to get out, but you need to remove that grey matter that has been gathering for 25 years!

There's a quick way to check need for cleaning: Remove blower motor resistor and use flashlight and digital camera to see inside. Here's what I found.

Evaporator Evaporator

Refrigerant and oil options

Mineral, PAO, PAG or POE?

R-12, R134a, RS-24 or Isceon 49? R-12 has been banned in Finland since ~1995.

Total R-12 capacity is 1,134 kg. When converted to RS-24, we used 80% of R-12 mass, totalling 0,910 kg.

This is a great video what happends to mineral oil with R134a: http://www.youtube.com/watch?v=LKz85ZcjquI