71 340 Duster A/C information
 

My friend just got the above car (and it is quite nice). The previous owner just finished installing a new A/C compressor. However the system was never charged.


I plan on ensuring new receiver dryer is in place, pulling vacuum and charging unit.


Can anyone tell me what oil is used for compressor and how many pounds of either R-12 or R-134A are used? I will be using R134A. And I'm assuming the compressor is stock.


I prefer charging by weight. Takes all the guesswork out of it.


Thanks

What type of compressor was installed OEM or the later round type The fittings would have been changed for 134 R12 is still available at least on Ebay

Actually, once you change the system from "exact as built factory" the charging weight is no longer all that valid.

Whatever you do CHECK superheat at the compressor. This is more difficult on automotive as they are designed to be running 'down the road.' Few of us have the huge shop fans needed to simulate air across the radiator.

I would shoot for at least 20 degrees F at the compressor, and at no time less than 10F. That is superheat, not measured temp.

You are going to want to measure this under the "worst" conditions for liquid return, which I believe is "stable" after the compartment is down to temp for a few minutes, and on a fairly warm day, IE the head pressure fairly high.

Your goal is to protect the compressor at all costs. Liquid refrigerant and compressors do not get along well

i think some of the aftermarket replacements use gases that are flammable. and some states have laws against the flammable gasses. i have seen people say you can just put propane in. so you put your car in the garage and the propane leeks up to the hot water tank pilot. what will the insurance co say?

My Motors Manual for '71 Plymouth Compact and Intermediate Vehicles V8 = 3.25 lbs. for 1 evaporator, 2 evaporators = 4.25 lbs.

3.25 lbs =52 oz. X .75 (134a) = 39 ounces.

Oil = 10-11 ounces.