Automotive Air Conditioning Information Forum

Newbie here... I have a 65 Olds Cutlass with factory air that I am getting up and running again... I pulled this setup off another car 30 years ago and at the time, my bad, when I started taking it off there was the slightest bit of pressure in the system even though it sat for many years.. Anyway... taped all the fittings shut to seal them from the elements and it sat for many years again...

The only thing I have re-used is a couple of steel lines and the evaporator. Everything else is new, condenser, hoses (eaton ez clip), drier and the compressor which will now be a new R4 unit. I also dumped the muffler and POA valve and installed a classic air POA eliminator with a cycling switch. I am now at the point where I am going to vacuum out the system as the evaporator has not been cleaned or replaced... Should have replaced it but nothing was available at the time.. now there is..

I looked up the AC oil which should be Pag 150? please correct me if I'm wrong. But I don't know how much I should use... Should I go with what the original system used for volume of oil?

I was thinking that I should add some oil to the compressor then vacuum the system with the new oil helping to flush it and see if it holds vacuum. Does this sound good so far?

If this is all good then I will start to charge with Dupont Suva R134A. I think these old cars used quite a bit of refridgerant so I will have to play it by (ear) eyeing the gauges.. Anyone who cares to guess at how much R134A I will need?

Any and all comments and suggestions will be greatly appreciated... I'm not new to A/C but its been 40 years since I did any AC work...

Thanks in advance for any advice

Why the choice of a R4 compressor? That unit really was not GM's finest hour. The V5 is a popular choice for hot rods since it is more reliable and has internal pressure control-- system does not need a POA valve or cycling at all. The "POA eliminator" system is going to suffer from annoying rapid cycling which leads to clutch wear. TXV systems were not intended to be controlled that way. It would be better to put a temperature sensor in the evaporator if you have a fixed displacement compressor.

Hadnt heard of the V5... It certainly wasn't an option when I ordered my Holley accessory drive kit I don't think ... The engine is a LS327.. I needed as much room as I could get which is why I went with the R4.. My unit has a new expansion valve as well... Will have to try it out at this point seeing as how its all together ..

The original factory setup called for 3 3/4 lbs of R12 and 10 oz of oil... Because I changed the compressor and dropped the muffler assembly I'm guessing the numbers are going to change. I'm thinking about 48 oz of R134A max and 8 oz of pag150.. Thoughts ?