AC Retrofit

[sblackmon]

I am changing over my R12 system to R134a. My system has not worked since I got it and the hoses are cracked. My question is does anybody know what kind and weight of oil to use. Also how much oil is needed?

[haysonj]

Originally Posted by sblackmon

I am changing over my R12 system to R134a. My system has not worked since I got it and the hoses are cracked. My question is does anybody know what kind and weight of oil to use. Also how much oil is needed?

First thing you need to have someone vacuum out the system you can't just throw some oil and refridgerant in it and expect it to work. You should also change your dryer and the high and low pressure fittings. To do it right you should also change the compressor but can get by without that. I spent almost $800 to get mine working the way I wanted, Good Luck. John

[sblackmon]

Actually the first thing you need to do is flush the system clean. I know all the steps. I have the new dryer and fittings. I have the flush kit and flush for the condenser, evaporate, etc. I have drained the oil out of the old compressor as best I can. I will barrow a vacuum. I have the pressure gauges. Just need to know the oil weight and volume.

[MARKDTN]

In my experience you will blow the front seal out of a used compressor in a short amount of time. I would pony up now for a compressor.

I don't have the shop manual in front of me, but the info you seek is in there. If you don't have a factory shop manual, I would highly recommend getting one.

[Bigdav160]

My question is does anybody know what kind and weight of oil to use. Also how much oil is needed?

R12 systems used 525 viscosity mineral oil.

Most, around here, will recommend ester oil for a retrofit. I believe it only comes in 100 VI

IIRC, the amount for the pickup is 10 ounces.

[mrein3]

Originally Posted by sblackmon

I am changing over my R12 system to R134a. My system has not worked since I got it and the hoses are cracked. My question is does anybody know what kind and weight of oil to use. Also how much oil is needed?

I did a pretty detailed writeup a while ago. Scroll down to post #8 for the oil I used...
http://67-72chevytrucks.com/vboard/s...d.php?t=478564

The compressor I'm using is a stock compressor off of a 1971 Monte Carlo. I've heard a lot about compressor failure but have yet to experience it.

Make sure you adjust your POA to work with R134a.

[sblackmon]

Thanks for all the info.